Trobalt

1 

ANNEX I 

SUMMARY OF PRODUCT CHARACTERISTICS 

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1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 50 mg film-coated tablets 
 
 
2. QUALITATIVE AND QUANTITATIVE COMPOSITION 
 
Each film-coated tablet contains 50 mg of retigabine. 
 
For the full list of excipients, see section 6.1. 
 
 
3. PHARMACEUTICAL FORM 
 
Film-coated tablet. 
 
Purple, round, film-coated tablets of 5.6 mm, marked with “RTG 50” on one side. 
 
 
4. CLINICAL PARTICULARS 
 
4.1 Therapeutic indications 
 
Trobalt is indicated as adjunctive treatment of drug-resistant partial onset seizures with or without 
secondary generalization in patients aged 18 years or older with epilepsy, where other appropriate 
combinations with other medicinal products have proved inadequate or have not been tolerated. 
 
4.2 Posology and method of administration 
 
Posology 
 
Trobalt must be titrated, according to individual patient response, in order to optimise the balance 
between efficacy and tolerability. 
 
The maximum total daily starting dose is 300 mg (100 mg three times daily). Thereafter, the total daily 
dose is increased by a maximum of 150 mg every week, according to the individual patient response 
and tolerability. An effective maintenance dose is expected to be between 600 mg/day and 
1,200 mg/day. 
 
The maximum total maintenance dose is 1,200 mg/day. The safety and efficacy of doses higher than 
1,200 mg/day have not been established. 
 
If patients miss one dose or more, it is recommended that they take a single dose as soon as they 
remember. 
 
After taking a missed dose, at least 3 hours should be allowed before the next dose and then the 
normal dosing schedule should be resumed. 
 
When withdrawing Trobalt, the dose must be gradually reduced over a period of at least 3 weeks (see 
section 4.4).  
 
Elderly (65 years of age and above) 
 
There are only limited data on the safety and efficacy of retigabine in patients aged 65 years and 
above. A reduction in the initial and maintenance dose of Trobalt is recommended in elderly patients. 

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The total daily starting dose is 150 mg/day and during the titration period the total daily dose should 
be increased by a maximum of 150 mg every week, according to the individual patient response and 
tolerability. Doses greater than 900 mg/day are not recommended (see sections 4.4 and 5.2). 
 
Renal impairment 
 
Retigabine and its metabolites are eliminated principally by renal excretion. 
 
No dose adjustment is required in patients with mild renal impairment (creatinine clearance 50 to 
80 ml/min; see section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe renal impairment (creatinine clearance <50 ml/min; see section 5.2). The total 
daily starting dose is 150 mg, and it is recommended that during the titration period, the total daily 
dose is increased by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
For patients with end-stage renal disease receiving haemodialysis, the three daily doses should be 
taken as usual on the dialysis day. In addition, a single supplemental dose is recommended 
immediately after haemodialysis. If breakthrough seizures occur towards the end of dialysis then an 
additional supplemental dose may be considered at the start of subsequent dialysis sessions. 
 
Hepatic impairment 
 
No dose reduction is required in patients with mild hepatic impairment (Child-Pugh score 5 to 6; see 
section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe hepatic impairment (Child-Pugh score ≥7; see section 5.2). The total daily starting 
dose is 150 mg, and it is recommended that during the titration period, the total daily dose is increased 
by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
Paediatric population 
 
The safety and efficacy of retigabine in children below 18 years of age has not yet been established 
(see section 5.2). Currently available pharmacokinetic data are described in section 5.2, but no 
recommendation on a posology can be made. 
 
 
Method of administration 
 
Trobalt is for oral use. The tablets must be taken in three divided doses each day.  The tablets should 
be swallowed whole, and not chewed, crushed or divided. 
 
Trobalt may be taken with or without food (see section 5.2). 
 
4.3 Contraindications 
 
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1. 
 
 
4.4 Special warnings and precautions for use 
 
Eye disorders 
 
Pigment changes (discolouration) of ocular tissues, including the retina have been reported in long-
term clinical studies with retigabine, sometimes but not always in conjunction with pigment changes 
of the skin, lips or nails (see below paragraph and section 4.8). Reversibility of retinal pigmentation 

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after retigabine discontinuation has been reported in some subjects. The long-term prognosis of these 
findings is currently unknown, but some of the reports have been associated with visual impairment.   
 
In addition a distinct form of macular abnormality with features of vitelliform maculopathy (see 
section 4.8) has also been identified, in most cases diagnosed with optical coherence tomography 
(OCT) imaging. The rate of progression of vitelliform maculopathy and its impact on retinal and 
macular function and vision is unclear. Vision abnormalities (field constriction, loss of central 
sensitivity, and reduced visual acuity) have been reported.  
 
All patients should undergo comprehensive ophthalmological examinations at baseline and at least 
every six months, which should include visual acuity, slit-lamp examination, dilated fundus 
photography, and macular OCT imaging. If retinal pigment changes, vitelliform maculopathy or vision 
changes are detected, treatment with Trobalt should only be continued after a careful re-assessment of 
the balance of benefits and risks. If continued, the patient should be monitored more closely. 
 
Skin disorders 
 
Pigment changes (discolouration) of the skin, lips or nails have been reported in long-term clinical 
studies with retigabine, sometimes but not always in conjunction with pigment changes of ocular 
tissues (see above paragraph and section 4.8). In patients who develop these changes, treatment with 
Trobalt should only be continued after a careful re-assessment  of the balance of benefits and risks. 
 
Urinary retention 
 
Urinary retention, dysuria and urinary hesitation were reported in controlled clinical studies with 
retigabine, generally within the first 8 weeks of treatment (see section 4.8). Trobalt must be used with 
caution in patients at risk of urinary retention, and it is recommended that patients are advised about 
the risk of these possible effects. 
 
QT interval 
 
A study of cardiac conduction in healthy subjects has demonstrated that retigabine titrated to 1,200 
mg/day produced a QT-prolonging effect. A mean increase in Individual Corrected QT Interval (QTcI) 
of up to 6.7 ms (upper bound of 95% one-sided CI 12.6 ms) was observed within 3 hours of dosing. 
Caution should be taken when Trobalt is prescribed with medicinal products known to increase 
QT interval and in patients with known prolonged QT interval, congestive cardiac failure, ventricular 
hypertrophy, hypokalaemia or hypomagnesaemia and in patients initiating treatment who are 65 years 
of age and above. 
 
In these patients it is recommended that an electrocardiogram (ECG) is recorded before initiation of 
treatment with Trobalt and in those with a corrected QT interval >440ms at baseline, an ECG should 
be recorded on reaching the maintenance dose. 
 
Psychiatric disorders 
 
Confusional state, psychotic disorders and hallucinations were reported in controlled clinical studies 
with retigabine (see section 4.8).  These effects generally occurred within the first 8 weeks of 
treatment, and frequently led to treatment withdrawal in affected patients. It is recommended that 
patients are advised about the risk of these possible effects. 
 

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Suicide risk 
 
Suicidal ideation and behaviour have been reported in patients treated with antiepileptic agents in 
several indications. A meta-analysis of randomised placebo-controlled trials of antiepileptic medicinal 
products has also shown a small increased risk of suicidal ideation and behaviour. The mechanism of 
this risk is not known and the available data do not exclude the possibility of an increased risk for 
retigabine. 
 
Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate 
treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical 
advice if signs of suicidal ideation or behaviour emerge. 
 
Elderly (65 years of age and above) 
 
Elderly patients may be at increased risk of central nervous system events, urinary retention and atrial 
fibrillation.  Trobalt must be used with caution in this population and a reduced initial and 
maintenance dose is recommended (see sections 4.2 and 5.2). 
 
Withdrawal seizures 
 
Trobalt must be withdrawn gradually to minimise the potential for rebound seizures.  It is 
recommended that the Trobalt dose is reduced over a period of at least 3 weeks, unless safety concerns 
require an abrupt withdrawal (see section 4.2). 
 
Laboratory tests 
 
Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine 
bilirubin, which can result in falsely elevated readings. 
 
 
4.5 Interaction with other medicinal products and other forms of interaction 
 
Interaction studies have only been performed in adults. 
 
Other antiepileptic medicinal products 
 
In vitro data indicated a low potential for interaction with other antiepileptic medicinal products (see 
section 5.2).  The drug interaction potential was, therefore, evaluated based on a pooled analysis 
across clinical studies and whilst not considered as robust as stand-alone clinical interaction studies, 
the results support the in vitro data. 
 
Based on these pooled data, retigabine did not cause clinically significant effects on the plasma trough 
concentrations of the following antiepileptic medicinal products: 
- carbamazepine, clobazam, clonazepam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 

phenobarbital, phenytoin, pregabalin, topiramate, valproate, zonisamide. 
 
Further, based on pooled data, there were no clinically significant effects of the following antiepileptic 
medicinal products on retigabine pharmacokinetics: 
- lamotrigine, levetiracetam, oxcarbazepine, topiramate, valproate.   
 
This analysis also showed no clinically significant effect of the inducers (phenytoin, carbamazepine 
and phenobarbital) on retigabine clearance. 
 
However, steady-state data from a limited number of patients in smaller phase II studies indicated that:  
-  phenytoin can reduce retigabine systemic exposure by 35%  
-  carbamazepine can reduce retigabine systemic exposure by 33%  

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Interaction with digoxin 
 
Data from an in vitro study showed that the N-acetyl metabolite of retigabine (NAMR) inhibited 
P-glycoprotein-mediated transport of digoxin in a concentration-dependent manner.  
 
Based on a study conducted in healthy volunteers, therapeutic doses of retigabine (600-1,200 mg/day) 
resulted in a minor (8-18%) increase in digoxin AUC following a single oral dose of digoxin. The 
increase did not appear to be dependent on retigabine dose and is not considered clinically relevant. 
There was no meaningful change in digoxin Cmax. No dose adjustment of digoxin is needed. 
 
Interaction with anaesthetics 
Trobalt may increase the duration of anaesthesia induced by some anaesthetics (for example thiopental 
sodium; see section 5.1). 
 
Interaction with alcohol 
 
Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual 
blurring in healthy volunteers. It is recommended that patients are advised about the possible effects 
on vision if they take Trobalt with alcohol. 
 
Oral contraceptives 
 
At retigabine doses of up to 750 mg/day, there was no clinically significant effect of retigabine on the 
pharmacokinetics of the estrogen (ethinyl estradiol) or progestogen (norethindrone) components of the 
oral contraceptive pill. In addition, there was no clinically significant effect of the low dose 
combination oral contraceptive pill on the pharmacokinetics of retigabine. 
 
 
4.6 Fertility, pregnancy and lactation 
 
Pregnancy 
 
Risk related to antiepileptic medicinal products in general 
Specialist advice should be given to women who are of childbearing potential. The need for treatment 
with antiepileptic medicinal products should be reviewed when a woman is planning to become 
pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic medicine 
therapy should be avoided as this may lead to breakthrough seizures that could have serious 
consequences for the woman and the unborn child.  
 
The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers 
treated with antiepileptic medicinal products compared with the expected incidence in the general 
population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular 
malformations and neural tube defects. Therapy with multiple antiepileptic medicinal products is 
associated with a higher risk of congenital malformations than monotherapy and therefore 
monotherapy should be used whenever possible.  
 
Risk related to Trobalt 
There are no adequate data from the use of retigabine in pregnant women. Animal studies are 
insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies 
were less than those reached in humans at recommended doses (see section 5.3). In a developmental 
study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in 
auditory startle response development of the offspring (see section 5.3). The clinical significance of 
this finding is not known.  
 
Trobalt is not recommended during pregnancy and in women of childbearing age, not using 
contraception. 

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Breastfeeding 
 
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown 
excretion of retagabine and/or its metabolites in breast milk. A decision on whether to 
continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made 
taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the 
woman. 
 
Fertility 
 
There were no treatment-related effects of retigabine on fertility in animal studies. However, the 
plasma levels achieved in these studies were less than those reached in humans at recommended doses 
(see section 5.3). 
 
The effect of retigabine on human fertility has not been established. 
 
4.7 Effects on ability to drive and use machines 
 
Adverse reactions such as dizziness, somnolence, diplopia and blurred vision were reported in 
controlled clinical studies, particularly during titration (see section 4.8). It is recommended that 
patients are advised about the risk of such adverse reactions at treatment initiation and following each 
titration step, and that they are advised not to drive or operate machinery until they have established 
how Trobalt affects them. 
 
4.8 Undesirable effects 
 
Summary of the safety profile 
 
In pooled safety data from three multicentre, randomised, double-blind, placebo-controlled studies, 
adverse reactions were generally mild to moderate in intensity, and were most commonly reported in 
the first 8 weeks of treatment. There was an apparent dose-relationship for dizziness, somnolence, 
confusional state, aphasia, coordination abnormal, tremor, balance disorder, memory impairment, gait 
disturbance, blurred vision and constipation. 
 
Adverse reactions that were most frequently reported to lead to discontinuation were dizziness, 
somnolence, fatigue and confusional state. 
 
Tabulated list of adverse reactions 
 
The following convention has been used for the classification of adverse reactions: 
 
Very common: ≥1/10 
Common:  ≥1/100 to <1/10 
Uncommon:  ≥1/1,000 to <1/100 
Rare: ≥1/10,000 to <1/1,000 
Very rare: <1/10,000. 
 
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Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. 
 
System Organ 
Class 
 

Very common Common Uncommon 

Metabolism and 
nutrition disorders 
 

 Weight increased 
Increased appetite 

 

Psychiatric 
disorders 
 

 Confusional state 
Psychotic disorders 
Hallucinations 
Disorientation 
Anxiety 
 

 

Nervous system 
disorders 
 

Dizziness 
Somnolence 
 

Amnesia 
Aphasia 
Coordination abnormal 
Vertigo 
Paraesthesia 
Tremor 
Balance disorder 
Memory impairment 
Dysphasia 
Dysarthria 
Disturbance in attention 
Gait disturbance 
Myoclonus 
 

Hypokinesia 

Eye disorders 
 

Pigment changes 
(discolouration) of 
ocular tissues, 
including the 
retina, have been 
observed after 
several years of 
treatment. Some 
of these reports 
have been 
associated with 
visual impairment. 
 

Diplopia 
Blurred vision 
Acquired Vitelliform 
Maculopathy 
 

 

Gastrointestinal 
disorders 

 Nausea 
Constipation 
Dyspepsia 
Dry mouth 
 

Dysphagia 

Hepatobiliary 
disorders 

 Increased liver function 
tests 
 

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System Organ 
Class 
 

Very common Common Uncommon 

Skin and 
subcutaneous 
disorders 
 

Blue-grey 
discolouration of 
the nails, lips 
and/or skin have 
been observed, 
generally at higher 
doses and after 
several years of 
treatment. 
 

 Skin rash 
Hyperhidrosis 

Renal and urinary 
disorders 
 

 Dysuria 
Urinary hesitation 
Haematuria 
Chromaturia 
 

Urinary retention 
Nephrolithiasis 

General disorders 
and administrative 
site conditions 

Fatigue Asthenia 
Malaise  
Peripheral oedema 
 

 

 
Description of selected adverse reactions 
 
Adverse reactions related to voiding dysfunction, including urinary retention, were reported in 5% of 
retigabine-treated patients in the pooled safety dataset (see section 4.4). The majority of events 
occurred in the first 8 weeks of treatment, and there was no apparent dose-relationship. 
 
In retigabine-treated patients in the pooled dataset, confusional state was reported in 9% of patients, 
hallucinations in 2% of patients and psychotic disorders in 1% of patients (see section 4.4). The 
majority of adverse reactions occurred in the first 8 weeks of treatment, and there was an apparent 
dose-relationship for confusional state only. 
Adverse event data from clinical trial subjects showed a rate of event of discolouration of the nails, 
lips, skin and/or mucosa per patient year of exposure of 3.6%. The cumulative incidences of an event 
at 1 year, 2 years, 3 years, 4 years and 5 years of exposure are approximately 1%, 1.8%, 4.4%, 10.2% 
and 16.7% respectively. 
 
Approximately 30-40% of clinical trial subjects who were being treated with retigabine and underwent 
a skin and/or ophthalmological examination had findings of discolouration of nails, lips, skin and/or 
mucosa or non-retinal ocular pigmentation, and approximately 15-30% of clinical trial subjects who 
were being treated with retigabine and underwent an ophthalmological examination had retinal 
pigmentation findings. In addition, cases of acquired vitelliform-type maculopathy have been 
identified, both in clinical studies and as spontaneous reports. 
 
Data from elderly patients indicates that they may be more likely to experience certain central nervous 
system events, including somnolence, amnesia, coordination abnormal, vertigo, tremor, balance 
disorder, memory impairment and gait disturbance. 
 
 
Reporting of suspected adverse reactions  
 
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It 
allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare 
professionals are asked to report any suspected adverse reactions via the national reporting system 
listed in Appendix V. 
 

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4.9 Overdose 
 
Symptoms and signs 
 
There is limited experience of overdose with retigabine. 
 
Retigabine overdoses in excess of 2,500 mg/day were reported during clinical studies. In addition to 
adverse reactions seen at therapeutic doses, symptoms of retigabine overdose included agitation, 
aggressive behaviour and irritability. There were no reported sequelae. 
 
In a study in volunteers, cardiac arrhythmia (cardiac arrest/asystole or ventricular tachycardia) 
occurred in two subjects within 3 hours of receiving a single 900 mg retigabine dose. The arrhythmias 
spontaneously resolved, and both volunteers recovered without sequelae. 
 
Management 
 
In the event of overdose, it is recommended that the patient is given appropriate supportive therapy as 
clinically indicated, including electrocardiogram (ECG) monitoring. Further management should be as 
recommended by the national poisons centre, where available. 
 
Haemodialysis has been shown to reduce the plasma concentrations of retigabine and NAMR by 
approximately 50%. 
 
 
5. PHARMACOLOGICAL PROPERTIES 
 
5.1  Pharmacodynamic properties 
 
Pharmacotherapeutic group: antiepileptics, other antiepileptics, ATC code: N03AX21. 
 
Mechanism of action 
 
Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are 
important determinants of neuronal activity. In vitro studies indicate that retigabine acts primarily 
through opening neuronal potassium channels (KCNQ2 [Kv7.2] and KCNQ3 [Kv7.3]). This stabilises 
the resting membrane potential and controls the sub-threshold electrical excitability in neurons, thus 
preventing the initiation of epileptiform action potential bursts. Mutations in the KCNQ channels 
underlie several human inheritable disorders, including epilepsy (KCNQ2 and 3). The mechanism of 
action of retigabine on potassium channels has been well documented, however other mechanisms by 
which retigabine may assert an antiepileptic effect have yet to be fully elucidated. 
 
In a range of seizure models, retigabine increased the threshold for seizure induction produced by 
maximal electroshock, pentylenetetrazol, picrotoxin and N-methyl-D-aspartate (NMDA). Retigabine 
also displayed inhibitory properties in multiple kindling models, for example, in the fully kindled state 
and in some cases during the kindling development. In addition, retigabine was effective in preventing 
status epilepticus seizures in rodents with cobalt-induced epileptogenic lesions, and inhibiting tonic 
extensor seizures in genetically susceptible mice. The relevance of these models to human epilepsy, 
however, is not known. 
 
Pharmacodynamic effects 
In rats, retigabine increased the sleep time induced by thiopental sodium from approximately 4 min to 
53 min, and the propofol-induced sleep time from approximately 8 min to 12 min. There was no effect 
on sleep time induced by halothane or methohexital sodium. Retigabine may increase the duration of 
anaesthesia induced by some anaesthetics (for example thiopental sodium). 
 

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Clinical efficacy of adjunctive retigabine therapy in partial onset seizures 
 
Three multicentre, randomized, double-blind, placebo-controlled studies in a total of 1239 adult 
patients have been conducted to assess the efficacy of retigabine as adjunctive therapy of partial onset 
seizures, with or without secondary generalisation. All patients enrolled were to have had seizures that 
were not adequately controlled with 1 to 3 concomitant antiepileptic medicinal products, and more 
than 75% of all patients were taking ≥2 concurrent antiepileptic medicinal products. Across all studies, 
patients had a mean duration of epilepsy of 22 years and a median baseline seizure frequency ranging 
from 8 to 12 per 28 days. Patients were randomized to placebo or retigabine at 600, 900 or 
1,200 mg/day (see Table 1). During an 8-week baseline period, patients had to experience ≥4 partial 
onset seizures per 28 days. Patients could not be seizure-free for ≥21 days. The duration of the 
maintenance phase was 8 or 12 weeks. 
 
The primary efficacy endpoints were: 
- percentage change in the 28-day total partial seizure frequency from baseline to the 

double-blind phase (titration and maintenance phases combined) in all three studies 
- responder rate (defined as the percentage of patients with a ≥50% reduction in 28-day total 

partial seizure frequency) from baseline to the maintenance phase (Studies 301 and 302 only). 
 
Retigabine was effective in adjunctive treatment of adults with partial onset seizures in three clinical 
studies (Table 1).  Retigabine was statistically significantly superior to placebo at 600 mg/day 
(one study), 900 mg/day (two studies) and 1,200 mg/day (two studies). 
 
The studies were not designed to evaluate specific combinations of antiepileptic medicinal products. 
Consequently, the efficacy and safety of retigabine when taken concomitantly with antiepileptic 
medicinal products that were less commonly used as background treatment in the clinical studies, 
including levetiracetam, has not been definitely shown. 
 
Table 1. Summary of percentage changes in 28-day total partial seizure frequency and responder 
rates 
 
Study  
(n=population in double-blind phase;  
n=population in maintenance phase) 
 

Placebo Retigabine 
600 

mg/day 
900 

mg/day 
1,200 

mg/day 

Study 205 (n=396; n=303) 
Total partial seizure frequency (median) % change  -13% -23% -29%* -35%* 
Responder rate (secondary endpoint) 
 

26% 28% 41% 41%* 

Study 301 (n=305; n=256) 
Total partial seizure frequency (median) % change -18% ~ ~ -44%* 
Responder rate  
 

23% ~ ~ 56%* 

Study 302 (n=538; n=471) 
Total partial seizure frequency (median) % change -16% -28%* -40%* ~ 
Responder rate  
 

19% 39%* 47%* ~ 

* Statistically significant, p≤0.05 
~ Dose not studied 
 
In open-label extensions of the three placebo-controlled studies, persistence of efficacy was 
maintained over an evaluation period of at least 12 months (365 patients). 
 

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Paediatric population 
 
The European Medicines Agency has waived the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 0 to below 2 years with Lennox Gastaut Syndrome (see section 4.2 
for information on paediatric use). 
 
The European Medicines Agency has deferred the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 2 to below 18 years with Lennox Gastaut Syndrome, and in 
paediatric patients aged 0 to below 18 years with partial onset seizures (see section 4.2 for information 
on paediatric use) . 
 
5.2 Pharmacokinetic properties 
 
Absorption 
 
After both single and multiple oral doses, retigabine is rapidly absorbed with median tmax values 
generally between 0.5 and 2 hours. Absolute oral bioavailability of retigabine relative to an 
intravenous dose is approximately 60%. 
 
Administration of retigabine with a high fat meal resulted in no change in the overall extent of 
retigabine absorption, but food reduced the between-subject variability in Cmax (23%) compared to the 
fasted state (41%), and led to an increase in Cmax (38%).  The effect of food on Cmax under usual 
clinical conditions is not expected to be clinically relevant.  Therefore Trobalt may be taken with or 
without food.  
 
Distribution 
 
Retigabine is approximately 80% bound to plasma protein over the concentration range of 0.1 to 
2 µg/ml. The steady state volume of distribution of retigabine is 2 to 3 l/kg following intravenous 
dosing. 
 
Biotransformation 
 
Retigabine is extensively metabolised in humans. A substantial fraction of the retigabine dose is 
converted to inactive N-glucuronides. Retigabine is also metabolised to an N-acetyl metabolite 
(NAMR) that is also subsequently glucuronidated. NAMR has antiepileptic activity, but is less potent 
than retigabine in animal seizure models. 
 
There is no evidence for hepatic oxidative metabolism of retigabine or NAMR by cytochrome P450 
enzymes.  Therefore, co-administration with inhibitors or inducers of cytochrome P450 enzymes is 
unlikely to affect the pharmacokinetics of retigabine or NAMR. 
 
In vitro studies using human liver microsomes showed little or no potential for retigabine to inhibit the 
major cytochrome P450 isoenzymes (including CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, 
CYP2D6, CYP2E1 and CYP3A4/5).  In addition, retigabine and NAMR did not induce CYP1A2 or 
CYP3A4/5 in human primary hepatocytes. Therefore, retigabine is unlikely to affect the 
pharmacokinetics of substrates of the major cytochrome P450 isoenzymes through inhibition or 
induction mechanisms. 
 

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Elimination 
 
Elimination of retigabine occurs via a combination of hepatic metabolism and renal excretion. A total 
of approximately 84% of the dose is recovered in the urine, including the N-acetyl metabolite (18%), 
N-glucuronides of the parent active substance and of the N-acetyl metabolite (24%), or parent active 
substance (36%). Only 14% of retigabine is excreted in the faeces. Retigabine has a plasma half-life of 
approximately 6 to 10 hours. The total clearance of retigabine from plasma following intravenous 
dosing is typically 0.4 to 0.6 l/h/kg. 
 
Linearity 
 
Retigabine pharmacokinetics are essentially linear over the single-dose range of 25 to 600 mg in 
healthy volunteers and up to 1,200 mg daily in patients with epilepsy, with no unexpected 
accumulation following repeated administration. 
 
Special patient populations 
 
Renal impairment 
In a single-dose study, retigabine AUC was increased by approximately 30% in volunteers with mild 
renal impairment (creatinine clearance 50 to 80 ml/min) and by approximately 100% in volunteers 
with moderate to severe renal impairment (creatinine clearance <50 ml/min), relative to healthy 
volunteers.  Adjustment of the Trobalt dose is recommended in patients with moderate to severe renal 
impairment but no adjustment of the Trobalt dose is recommended in patients with mild renal 
impairment (see section 4.2).  
 
In a single-dose study in healthy volunteers and subjects with end stage renal disease, the retigabine 
AUC was increased by approximately 100% in the subjects with end stage renal disease relative to 
healthy volunteers.  
 
In a second single-dose study in subjects with end stage renal disease receiving chronic haemodialysis 
(n= 8), initiation of dialysis at approximately 4 hours after a single dose of retigabine (100 mg) 
resulted in a median reduction in retigabine plasma concentrations of 52% from the start to end of 
dialysis. The percentage decrease in plasma concentration during dialysis ranged from 34% to 60% 
except for one subject who had a 17% reduction. 
 
Hepatic impairment 
In a single-dose study, there were no clinically significant effects on retigabine AUC in volunteers 
with mild hepatic impairment (Child-Pugh score 5 to 6).  The retigabine AUC was increased by 
approximately 50% in volunteers with moderate hepatic impairment (Child-Pugh score 7 to 9) and by 
approximately 100% in volunteers with severe hepatic impairment (Child-Pugh score >9), relative to 
healthy volunteers. Adjustment of the Trobalt dose is recommended in patients with moderate or 
severe hepatic impairment (see section 4.2). 
 
Body weight 
In a population pharmacokinetic analysis, retigabine clearance increased with increasing body surface 
area. However, this increase is not considered to be clinically meaningful, and since retigabine is 
titrated according to individual patient response and tolerability, dose-adjustments are not required on 
the basis of body weight. 
 
Elderly (65 years of age and above) 
In a single-dose study, retigabine was eliminated more slowly by healthy elderly volunteers 
(66 to 82 years of age) relative to healthy young adult volunteers, resulting in a higher AUC 
(approximately 40 to 50%) and longer terminal half-life (30%) (see section 4.2). 
 

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Gender 
The results of a single-dose study showed that in young adult volunteers, retigabine Cmax was 
approximately 65% higher in females than in males, and in elderly volunteers (66 to 82 years of age), 
retigabine Cmax was approximately 75% higher in females compared with males. When Cmax was 
normalized for weight, the values were approximately 30% higher in young females than in males and 
40% higher in elderly females compared with males. However, there was no apparent gender 
difference in weight-normalized clearance, and since retigabine is titrated according to individual 
patient response and tolerability, dose-adjustments are not required on the basis of gender. 
 
Race 
A post-hoc analysis across multiple healthy volunteer studies demonstrated a 20% reduction in 
retigabine clearance in healthy black volunteers relative to healthy Caucasian volunteers. However, 
this effect is not considered clinically significant, therefore no adjustment of the Trobalt dose is 
recommended. 
 
Paediatric population 
The pharmacokinetics of retigabine in children below 12 years of age have not been investigated. 
 
An open-label, multiple dose pharmacokinetic, safety and tolerability study in five subjects aged 
between 12 years to less than 18 years with partial onset seizures determined that the 
pharmacokinetics of retigabine in adolescents were consistent with the pharmacokinetics of retigabine 
in adults.  However, efficacy and safety of retigabine have not been determined in adolescents. 
 
 
5.3 Preclinical safety data 
 
Maximum doses in repeat dose toxicity studies were limited by the exaggerated pharmacologic effects 
of retigabine (including ataxia, hypokinesia and tremor). At no observed effect levels, animal exposure 
in these studies was generally less than that reached in humans at recommended clinical doses. 
 
Distension of the gall bladder was seen in studies with dogs, but there was no evidence of cholestasis 
or other signs of gall bladder dysfunction, and bile ejection volume was unchanged. The gall bladder 
distension in the dog resulted in focal compression of the liver. No signs of gall bladder dysfunction 
were seen clinically. 
 
Non-clinical data reveal no special hazard for humans based on studies of genotoxicity or carcinogenic 
potential. 
 
Reproductive toxicology 
 
Retigabine had no effect on fertility or general reproductive performance. 
 
In rats, retigabine and/or its metabolites crossed the placenta resulting in tissue concentrations that 
were similar in dams and foetuses. 
 
There was no evidence of teratogenicity following administration of retigabine to pregnant animals 
during the period of organogenesis. In a study of peri- and post-natal development in rats, retigabine 
was associated with increased perinatal mortality following administration during pregnancy. In 
addition, there was a delay in auditory startle response development. These findings were apparent at 
exposure levels lower than those obtained with clinically recommended doses and were accompanied 
by maternal toxicities (including ataxia, hypokinesia, tremor and reduced body weight gain). The 
maternal toxicities interfered with higher dosing of the dams and hence deduction of safety margins 
with regard to human therapy.  
 
 

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6. PHARMACEUTICAL PARTICULARS 
 
6.1 List of excipients 
 
Tablet core 
 
Croscarmellose sodium 
Hypromellose 
Magnesium stearate 
Microcrystalline cellulose. 
 
Film-coating 
 
50 mg tablets: 
Polyvinyl alcohol  
Titanium dioxide (E171) 
Talc (E553b) 
Indigo carmine aluminium lake (E132) 
Carmine (E120). 
Lecithin (SOY) 
Xanthan gum 
 
6.2 Incompatibilities 
 
Not applicable. 
 
6.3 Shelf life 
 
3 years 
 
6.4 Special precautions for storage 
 
This medicinal product does not require any special storage conditions 
 
6.5 Nature and contents of container 
 
50 mg tablets:  
Opaque PVC-PVDC-aluminium foil blisters. Packs containing 21or 84 film-coated tablets. 
 
Not all pack sizes may be marketed. 
 
6.6 Special precautions for disposal  
 
No special requirements. 
 
 
7. MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS  
United Kingdom 
 
 
 

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8. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/001, EU/1/11/681/002 
 
 
 
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION 
 
Date of first authorisation: 28 March 2011  
Date of latest renewal: 14 January 2016 
 
10. DATE OF REVISION OF THE TEXT 
 
 
 
 
Detailed information on this medicinal product is available on the website of the European Medicines 
Agency http://www.ema.europa.eu. 

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1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 100 mg film-coated tablets 
 
 
2. QUALITATIVE AND QUANTITATIVE COMPOSITION 
 
Each film-coated tablet contains 100 mg of retigabine. 
 
For the full list of excipients, see section 6.1. 
 
 
3. PHARMACEUTICAL FORM 
 
Film-coated tablet. 
 
Green, round, film-coated tablets of 7.1 mm, marked with “RTG 100” on one side. 
 
 
4. CLINICAL PARTICULARS 
 
4.1 Therapeutic indications 
 
Trobalt is indicated as adjunctive treatment of drug-resistant partial onset seizures with or without 
secondary generalization in patients aged 18 years or older with epilepsy, where other appropriate 
combinations with other medicinal products have proved inadequate or have not been tolerated. 
 
4.2 Posology and method of administration 
 
Posology 
 
Trobalt must be titrated, according to individual patient response, in order to optimise the balance 
between efficacy and tolerability. 
 
The maximum total daily starting dose is 300 mg (100 mg three times daily). Thereafter, the total daily 
dose is increased by a maximum of 150 mg every week, according to the individual patient response 
and tolerability. An effective maintenance dose is expected to be between 600 mg/day and 
1,200 mg/day. 
 
The maximum total maintenance dose is 1,200 mg/day. The safety and efficacy of doses higher than 
1,200 mg/day have not been established. 
 
If patients miss one dose or more, it is recommended that they take a single dose as soon as they 
remember. 
 
After taking a missed dose, at least 3 hours should be allowed before the next dose and then the 
normal dosing schedule should be resumed. 
 
When withdrawing Trobalt, the dose must be gradually reduced over a period of at least 3 weeks (see 
section 4.4).  
 
Elderly (65 years of age and above) 
 
There are only limited data on the safety and efficacy of retigabine in patients aged 65 years and 
above. A reduction in the initial and maintenance dose of Trobalt is recommended in elderly patients. 

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The total daily starting dose is 150 mg/day and during the titration period the total daily dose should 
be increased by a maximum of 150 mg every week, according to the individual patient response and 
tolerability. Doses greater than 900 mg/day are not recommended (see sections 4.4 and 5.2). 
 
Renal impairment 
 
Retigabine and its metabolites are eliminated principally by renal excretion. 
 
No dose adjustment is required in patients with mild renal impairment (creatinine clearance 50 to 
80 ml/min; see section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe renal impairment (creatinine clearance <50 ml/min; see section 5.2). The total 
daily starting dose is 150 mg, and it is recommended that during the titration period, the total daily 
dose is increased by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
For patients with end-stage renal disease receiving haemodialysis, the three daily doses should be 
taken as usual on the dialysis day. In addition, a single supplemental dose is recommended 
immediately after haemodialysis. If breakthrough seizures occur towards the end of dialysis then an 
additional supplemental dose may be considered at the start of subsequent dialysis sessions. 
 
Hepatic impairment 
 
No dose reduction is required in patients with mild hepatic impairment (Child-Pugh score 5 to 6; see 
section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe hepatic impairment (Child-Pugh score ≥7; see section 5.2). The total daily starting 
dose is 150 mg, and it is recommended that during the titration period, the total daily dose is increased 
by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
Paediatric population 
 
The safety and efficacy of retigabine in children below 18 years of age has not yet been established 
(see section 5.2). Currently available pharmacokinetic data are described in section 5.2, but no 
recommendation on a posology can be made. 
 
 
Method of administration 
 
Trobalt is for oral use. The tablets must be taken in three divided doses each day.  The tablets should 
be swallowed whole, and not chewed, crushed or divided. 
 
Trobalt may be taken with or without food (see section 5.2). 
 
4.3 Contraindications 
 
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1. 
 
4.4 Special warnings and precautions for use 
 
Eye disorders 
 
Pigment changes (discolouration) of ocular tissues, including the retina have been reported in long-
term clinical studies with retigabine, sometimes but not always in conjunction with pigment changes 
of the skin, lips or nails (see below paragraph and section 4.8). Reversibility of retinal pigmentation 

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after retigabine discontinuation has been reported in some subjects. The long-term prognosis of these 
findings is currently unknown, but some of the reports have been associated with visual impairment.   
 
In addition a distinct form of macular abnormality with features of vitelliform maculopathy (see 
section 4.8) has also been identified, in most cases diagnosed with optical coherence tomography 
(OCT) imaging. The rate of progression of vitelliform maculopathy and its impact on retinal and 
macular function and vision is unclear. Vision abnormalities (field constriction, loss of central 
sensitivity, and reduced visual acuity) have been reported.  
 
All patients should undergo comprehensive ophthalmological examinations at baseline and at least 
every six months, which should include visual acuity, slit-lamp examination, dilated fundus 
photography, and macular OCT imaging. If retinal pigment changes, vitelliform maculopathy or vision 
changes are detected, treatment with Trobalt should only be continued after a careful re-assessment of 
the balance of benefits and risks. If continued, the patient should be monitored more closely. 
 
Skin disorders 
 
Pigment changes (discolouration) of the skin, lips or nails have been reported in long-term clinical 
studies with retigabine, sometimes but not always in conjunction with pigment changes of ocular 
tissues (see above paragraph and section 4.8). In patients who develop these changes, treatment with 
Trobalt should only be continued after a careful re-assessment  of the balance of benefits and risks. 
 
Urinary retention 
 
Urinary retention, dysuria and urinary hesitation were reported in controlled clinical studies with 
retigabine, generally within the first 8 weeks of treatment (see section 4.8). Trobalt must be used with 
caution in patients at risk of urinary retention, and it is recommended that patients are advised about 
the risk of these possible effects. 
 
QT interval 
 
A study of cardiac conduction in healthy subjects has demonstrated that retigabine titrated to 1,200 
mg/day produced a QT-prolonging effect. A mean increase in Individual Corrected QT Interval (QTcI) 
of up to 6.7 ms (upper bound of 95% one-sided CI 12.6 ms) was observed within 3 hours of dosing. 
Caution should be taken when Trobalt is prescribed with medicinal products known to increase 
QT interval and in patients with known prolonged QT interval, congestive cardiac failure, ventricular 
hypertrophy, hypokalaemia or hypomagnesaemia and in patients initiating treatment who are 65 years 
of age and above. 
 
In these patients it is recommended that an electrocardiogram (ECG) is recorded before initiation of 
treatment with Trobalt and in those with a corrected QT interval >440ms at baseline, an ECG should 
be recorded on reaching the maintenance dose. 
 
Psychiatric disorders 
 
Confusional state, psychotic disorders and hallucinations were reported in controlled clinical studies 
with retigabine (see section 4.8).  These effects generally occurred within the first 8 weeks of 
treatment, and frequently led to treatment withdrawal in affected patients. It is recommended that 
patients are advised about the risk of these possible effects. 
 

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Suicide risk 
 
Suicidal ideation and behaviour have been reported in patients treated with antiepileptic agents in 
several indications. A meta-analysis of randomised placebo-controlled trials of antiepileptic medicinal 
products has also shown a small increased risk of suicidal ideation and behaviour. The mechanism of 
this risk is not known and the available data do not exclude the possibility of an increased risk for 
retigabine. 
 
Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate 
treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical 
advice if signs of suicidal ideation or behaviour emerge. 
 
Elderly (65 years of age and above) 
 
Elderly patients may be at increased risk of central nervous system events, urinary retention and atrial 
fibrillation.  Trobalt must be used with caution in this population and a reduced initial and 
maintenance dose is recommended (see sections 4.2 and 5.2). 
 
Withdrawal seizures 
 
Trobalt must be withdrawn gradually to minimise the potential for rebound seizures.  It is 
recommended that the Trobalt dose is reduced over a period of at least 3 weeks, unless safety concerns 
require an abrupt withdrawal (see section 4.2). 
 
Laboratory tests 
 
Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine 
bilirubin, which can result in falsely elevated readings. 
 
 
4.5 Interaction with other medicinal products and other forms of interaction 
 
Interaction studies have only been performed in adults. 
 
Other antiepileptic medicinal products 
 
In vitro data indicated a low potential for interaction with other antiepileptic medicinal products (see 
section 5.2).  The drug interaction potential was, therefore, evaluated based on a pooled analysis 
across clinical studies and whilst not considered as robust as stand-alone clinical interaction studies, 
the results support the in vitro data. 
 
Based on these pooled data, retigabine did not cause clinically significant effects on the plasma trough 
concentrations of the following antiepileptic medicinal products: 
- carbamazepine, clobazam, clonazepam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 

phenobarbital, phenytoin, pregabalin, topiramate, valproate, zonisamide. 
 
Further, based on pooled data, there were no clinically significant effects of the following antiepileptic 
medicinal products on retigabine pharmacokinetics: 
- lamotrigine, levetiracetam, oxcarbazepine, topiramate, valproate.   
This analysis also showed no clinically significant effect of the inducers (phenytoin, carbamazepine 
and phenobarbital) on retigabine clearance. 
 
However, steady-state data from a limited number of patients in smaller phase II studies indicated that:  
-  phenytoin can reduce retigabine systemic exposure by 35% 
-  carbamazepine can reduce retigabine systemic exposure by 33% 

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Interaction with digoxin 
 
Data from an in vitro study showed that the N-acetyl metabolite of retigabine (NAMR) inhibited 
P-glycoprotein-mediated transport of digoxin in a concentration-dependent manner.  
 
Based on a study conducted in healthy volunteers, therapeutic doses of retigabine (600-1,200 mg/day) 
resulted in a minor (8-18%) increase in digoxin AUC following a single oral dose of digoxin. The 
increase did not appear to be dependent on retigabine dose and is not considered clinically relevant. 
There was no meaningful change in digoxin Cmax. No dose adjustment of digoxin is needed. 
 
Interaction with anaesthetics 
Trobalt may increase the duration of anaesthesia induced by some anaesthetics (for example thiopental 
sodium; see section 5.1). 
 
Interaction with alcohol 
 
Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual 
blurring in healthy volunteers. It is recommended that patients are advised about the possible effects 
on vision if they take Trobalt with alcohol. 
 
Oral contraceptives 
 
At retigabine doses of up to 750 mg/day, there was no clinically significant effect of retigabine on the 
pharmacokinetics of the estrogen (ethinyl estradiol) or progestogen (norethindrone) components of the 
oral contraceptive pill. In addition, there was no clinically significant effect of the low dose 
combination oral contraceptive pill on the pharmacokinetics of retigabine. 
 
 
4.6 Fertility, pregnancy and lactation 
 
Pregnancy 
 
Risk related to antiepileptic medicinal products in general 
Specialist advice should be given to women who are of childbearing potential. The need for treatment 
with antiepileptic medicinal products should be reviewed when a woman is planning to become 
pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic medicine 
therapy should be avoided as this may lead to breakthrough seizures that could have serious 
consequences for the woman and the unborn child.  
 
The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers 
treated with antiepileptic medicinal products compared with the expected incidence in the general 
population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular 
malformations and neural tube defects. Therapy with multiple antiepileptic medicinal products is 
associated with a higher risk of congenital malformations than monotherapy and therefore 
monotherapy should be used whenever possible. 
 
Risk related to Trobalt 
There are no adequate data from the use of retigabine in pregnant women. Animal studies are 
insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies 
were less than those reached in humans at recommended doses (see section 5.3). In a developmental 
study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in 
auditory startle response development of the offspring (see section 5.3). The clinical significance of 
this finding is not known.  
 
Trobalt is not recommended during pregnancy and in women of childbearing age, not using 
contraception. 

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Breastfeeding 
 
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown 
excretion of retagabine and/or its metabolites in breast milk. A decision on whether to 
continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made 
taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the 
woman. 
 
Fertility 
 
There were no treatment-related effects of retigabine on fertility in animal studies. However, the 
plasma levels achieved in these studies were less than those reached in humans at recommended doses 
(see section 5.3). 
 
The effect of retigabine on human fertility has not been established. 
 
4.7 Effects on ability to drive and use machines 
 
Adverse reactions such as dizziness, somnolence, diplopia and blurred vision were reported in 
controlled clinical studies, particularly during titration (see section 4.8). It is recommended that 
patients are advised about the risk of such adverse reactions at treatment initiation and following each 
titration step, and that they are advised not to drive or operate machinery until they have established 
how Trobalt affects them. 
 
4.8 Undesirable effects 
 
Summary of the safety profile 
 
In pooled safety data from three multicentre, randomised, double-blind, placebo-controlled studies, 
adverse reactions were generally mild to moderate in intensity, and were most commonly reported in 
the first 8 weeks of treatment. There was an apparent dose-relationship for dizziness, somnolence, 
confusional state, aphasia, coordination abnormal, tremor, balance disorder, memory impairment, gait 
disturbance, blurred vision and constipation. 
 
Adverse reactions that were most frequently reported to lead to discontinuation were dizziness, 
somnolence, fatigue and confusional state. 
 
Tabulated list of adverse reactions 
 
The following convention has been used for the classification of adverse reactions: 
 
Very common: ≥1/10 
Common:  ≥1/100 to <1/10 
Uncommon:  ≥1/1,000 to <1/100 
Rare: ≥1/10,000 to <1/1,000 
Very rare: <1/10,000. 
 
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Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. 
 
System Organ 
Class 
 

Very common Common Uncommon 

Metabolism and 
nutrition disorders 
 

 Weight increased 
Increased appetite 

 

Psychiatric 
disorders 
 

 Confusional state 
Psychotic disorders 
Hallucinations 
Disorientation 
Anxiety 
 

 

Nervous system 
disorders 
 

Dizziness 
Somnolence 
 

Amnesia 
Aphasia 
Coordination abnormal 
Vertigo 
Paraesthesia 
Tremor 
Balance disorder 
Memory impairment 
Dysphasia 
Dysarthria 
Disturbance in attention 
Gait disturbance 
Myoclonus 
 

Hypokinesia 

Eye disorders 
 

Pigment changes 
(discolouration) 
of ocular tissues, 
including the 
retina, have been 
observed after 
several years of 
treatment. Some 
of these reports 
have been 
associated with 
visual 
impairment. 
 

Diplopia 
Blurred vision 
Acquired Vitelliform 
Maculopathy 
 
 

 

Gastrointestinal 
disorders 

 Nausea 
Constipation 
Dyspepsia 
Dry mouth 
 

Dysphagia 

Hepatobiliary 
disorders 

 Increased liver function 
tests 
 

 
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System Organ 
Class 
 

Very common Common Uncommon 

Skin and 
subcutaneous 
disorders 
 

Blue-grey 
discolouration of 
the nails, lips 
and/or skin have 
been observed, 
generally at 
higher doses and 
after several years 
of treatment. 
 

 Skin rash 
Hyperhidrosis 

Renal and urinary 
disorders 
 

 Dysuria 
Urinary hesitation 
Haematuria 
Chromaturia 
 

Urinary retention 
Nephrolithiasis 

General disorders 
and administrative 
site conditions 

Fatigue Asthenia 
Malaise  
Peripheral oedema 
 

 

 
Description of selected adverse reactions 
Adverse reactions related to voiding dysfunction, including urinary retention, were reported in 5% of 
retigabine-treated patients in the pooled safety dataset (see section 4.4). The majority of events 
occurred in the first 8 weeks of treatment, and there was no apparent dose-relationship. 
 
In retigabine-treated patients in the pooled dataset, confusional state was reported in 9% of patients, 
hallucinations in 2% of patients and psychotic disorders in 1% of patients (see section 4.4). The 
majority of adverse reactions occurred in the first 8 weeks of treatment, and there was an apparent 
dose-relationship for confusional state only. 
 
Adverse event data from clinical trial subjects showed a rate of event of discolouration of the nails, 
lips, skin and/or mucosa per patient year of exposure of 3.6%. The cumulative incidences of an event 
at 1 year, 2 years, 3 years, 4 years and 5 years of exposure are approximately 1%, 1.8%, 4.4%, 10.2% 
and 16.7% respectively. 
 
Approximately 30-40% of clinical trial subjects who were being treated with retigabine and underwent 
a skin and/or ophthalmological examination had findings of discolouration of nails, lips, skin and/or 
mucosa or non-retinal ocular pigmentation, and approximately 15-30% of clinical trial subjects who 
were being treated with retigabine and underwent an ophthalmological examination had retinal 
pigmentation findings. In addition, cases of acquired vitelliform-type maculopathy have been 
identified, both in clinical studies and as spontaneous reports. 
 
Data from elderly patients indicates that they may be more likely to experience certain central nervous 
system events, including somnolence, amnesia, coordination abnormal, vertigo, tremor, balance 
disorder, memory impairment and gait disturbance. 
 
Reporting of suspected adverse reactions  
 
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It 
allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare 
professionals are asked to report any suspected adverse reactions via the national reporting system 
listed in Appendix V. 
 

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4.9 Overdose 
 
Symptoms and signs 
There is limited experience of overdose with retigabine. 
 
Retigabine overdoses in excess of 2,500 mg/day were reported during clinical studies. In addition to 
adverse reactions seen at therapeutic doses, symptoms of retigabine overdose included agitation, 
aggressive behaviour and irritability. There were no reported sequelae. 
 
In a study in volunteers, cardiac arrhythmia (cardiac arrest/asystole or ventricular tachycardia) 
occurred in two subjects within 3 hours of receiving a single 900 mg retigabine dose. The arrhythmias 
spontaneously resolved, and both volunteers recovered without sequelae. 
 
Management 
 
In the event of overdose, it is recommended that the patient is given appropriate supportive therapy as 
clinically indicated, including electrocardiogram (ECG) monitoring. Further management should be as 
recommended by the national poisons centre, where available. 
 
Haemodialysis has been shown to reduce the plasma concentrations of retigabine and NAMR by 
approximately 50%. 
 
 
5. PHARMACOLOGICAL PROPERTIES 
 
5.1  Pharmacodynamic properties 
 
Pharmacotherapeutic group: antiepileptics, other antiepileptics, ATC code: N03AX21. 
 
Mechanism of action 
 
Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are 
important determinants of neuronal activity. In vitro studies indicate that retigabine acts primarily 
through opening neuronal potassium channels (KCNQ2 [Kv7.2] and KCNQ3 [Kv7.3]). This stabilises 
the resting membrane potential and controls the sub-threshold electrical excitability in neurons, thus 
preventing the initiation of epileptiform action potential bursts. Mutations in the KCNQ channels 
underlie several human inheritable disorders, including epilepsy (KCNQ2 and 3). The mechanism of 
action of retigabine on potassium channels has been well documented, however other mechanisms by 
which retigabine may assert an antiepileptic effect have yet to be fully elucidated. 
 
In a range of seizure models, retigabine increased the threshold for seizure induction produced by 
maximal electroshock, pentylenetetrazol, picrotoxin and N-methyl-D-aspartate (NMDA). Retigabine 
also displayed inhibitory properties in multiple kindling models, for example, in the fully kindled state 
and in some cases during the kindling development. In addition, retigabine was effective in preventing 
status epilepticus seizures in rodents with cobalt-induced epileptogenic lesions, and inhibiting tonic 
extensor seizures in genetically susceptible mice. The relevance of these models to human epilepsy, 
however, is not known. 
 
Pharmacodynamic effects 
 
In rats, retigabine increased the sleep time induced by thiopental sodium from approximately 4 min to 
53 min, and the propofol-induced sleep time from approximately 8 min to 12 min. There was no effect 
on sleep time induced by halothane or methohexital sodium. Retigabine may increase the duration of 
anaesthesia induced by some anaesthetics (for example thiopental sodium). 
 

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Clinical efficacy of adjunctive retigabine therapy in partial onset seizures 
 
Three multicentre, randomized, double-blind, placebo-controlled studies in a total of 1239 adult 
patients have been conducted to assess the efficacy of retigabine as adjunctive therapy of partial onset 
seizures, with or without secondary generalisation. All patients enrolled were to have had seizures that 
were not adequately controlled with 1 to 3 concomitant antiepileptic medicinal products, and more 
than 75% of all patients were taking ≥2 concurrent antiepileptic medicinal products. Across all studies, 
patients had a mean duration of epilepsy of 22 years and a median baseline seizure frequency ranging 
from 8 to 12 per 28 days. Patients were randomized to placebo or retigabine at 600, 900 or 
1,200 mg/day (see Table 1). During an 8-week baseline period, patients had to experience ≥4 partial 
onset seizures per 28 days. Patients could not be seizure-free for ≥21 days. The duration of the 
maintenance phase was 8 or 12 weeks. 
 
The primary efficacy endpoints were: 
- percentage change in the 28-day total partial seizure frequency from baseline to the 

double-blind phase (titration and maintenance phases combined) in all three studies 
- responder rate (defined as the percentage of patients with a ≥50% reduction in 28-day total 

partial seizure frequency) from baseline to the maintenance phase (Studies 301 and 302 only). 
 
Retigabine was effective in adjunctive treatment of adults with partial onset seizures in three clinical 
studies (Table 1).  Retigabine was statistically significantly superior to placebo at 600 mg/day 
(one study), 900 mg/day (two studies) and 1,200 mg/day (two studies). 
 
The studies were not designed to evaluate specific combinations of antiepileptic medicinal products. 
Consequently, the efficacy and safety of retigabine when taken concomitantly with antiepileptic 
medicinal products that were less commonly used as background treatment in the clinical studies, 
including levetiracetam, has not been definitely shown. 
 
Table 1. Summary of percentage changes in 28-day total partial seizure frequency and responder 
rates 
 
Study  
(n=population in double-blind phase;  
n=population in maintenance phase) 
 

Placebo Retigabine 
600 

mg/day 
900 

mg/day 
1,200 

mg/day 

Study 205 (n=396; n=303) 
Total partial seizure frequency (median) % change  -13% -23% -29%* -35%* 
Responder rate (secondary endpoint) 
 

26% 28% 41% 41%* 

Study 301 (n=305; n=256) 
Total partial seizure frequency (median) % change -18% ~ ~ -44%* 
Responder rate  
 

23% ~ ~ 56%* 

Study 302 (n=538; n=471) 
Total partial seizure frequency (median) % change -16% -28%* -40%* ~ 
Responder rate  
 

19% 39%* 47%* ~ 

* Statistically significant, p≤0.05 
~ Dose not studied 
 
In open-label extensions of the three placebo-controlled studies, persistence of efficacy was 
maintained over an evaluation period of at least 12 months (365 patients). 
 

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Paediatric population 
 
The European Medicines Agency has waived the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 0 to below 2 years with Lennox Gastaut Syndrome (see section 4.2 
for information on paediatric use). 
 
The European Medicines Agency has deferred the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 2 to below 18 years with Lennox Gastaut Syndrome, and in 
paediatric patients aged 0 to below 18 years with partial onset seizures (see section 4.2 for information 
on paediatric use). 
 
5.2 Pharmacokinetic properties 
 
Absorption 
 
After both single and multiple oral doses, retigabine is rapidly absorbed with median tmax values 
generally between 0.5 and 2 hours. Absolute oral bioavailability of retigabine relative to an 
intravenous dose is approximately 60%. 
 
Administration of retigabine with a high fat meal resulted in no change in the overall extent of 
retigabine absorption, but food reduced the between-subject variability in Cmax (23%) compared to the 
fasted state (41%), and led to an increase in Cmax (38%).  The effect of food on Cmax under usual 
clinical conditions is not expected to be clinically relevant.  Therefore Trobalt may be taken with or 
without food.  
 
Distribution 
 
Retigabine is approximately 80% bound to plasma protein over the concentration range of 0.1 to 
2 µg/ml. The steady state volume of distribution of retigabine is 2 to 3 l/kg following intravenous 
dosing. 
 
Biotransformation 
 
Retigabine is extensively metabolised in humans. A substantial fraction of the retigabine dose is 
converted to inactive N-glucuronides. Retigabine is also metabolised to an N-acetyl metabolite 
(NAMR) that is also subsequently glucuronidated. NAMR has antiepileptic activity, but is less potent 
than retigabine in animal seizure models. 
 
There is no evidence for hepatic oxidative metabolism of retigabine or NAMR by cytochrome P450 
enzymes.  Therefore, co-administration with inhibitors or inducers of cytochrome P450 enzymes is 
unlikely to affect the pharmacokinetics of retigabine or NAMR. 
 
 
In vitro studies using human liver microsomes showed little or no potential for retigabine to inhibit the 
major cytochrome P450 isoenzymes (including CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, 
CYP2D6, CYP2E1 and CYP3A4/5).  In addition, retigabine and NAMR did not induce CYP1A2 or 
CYP3A4/5 in human primary hepatocytes. Therefore, retigabine is unlikely to affect the 
pharmacokinetics of substrates of the major cytochrome P450 isoenzymes through inhibition or 
induction mechanisms. 
 

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Elimination 
 
Elimination of retigabine occurs via a combination of hepatic metabolism and renal excretion. A total 
of approximately 84% of the dose is recovered in the urine, including the N-acetyl metabolite (18%), 
N-glucuronides of the parent active substance and of the N-acetyl metabolite (24%), or parent active 
substance (36%). Only 14% of retigabine is excreted in the faeces. Retigabine has a plasma half-life of 
approximately 6 to 10 hours. The total clearance of retigabine from plasma following intravenous 
dosing is typically 0.4 to 0.6 l/h/kg. 
 
Linearity 
 
Retigabine pharmacokinetics are essentially linear over the single-dose range of 25 to 600 mg in 
healthy volunteers and up to 1,200 mg daily in patients with epilepsy, with no unexpected 
accumulation following repeated administration. 
 
Special patient populations 
 
Renal impairment 
In a single-dose study, retigabine AUC was increased by approximately 30% in volunteers with mild 
renal impairment (creatinine clearance 50 to 80 ml/min) and by approximately 100% in volunteers 
with moderate to severe renal impairment (creatinine clearance <50 ml/min), relative to healthy 
volunteers.  Adjustment of the Trobalt dose is recommended in patients with moderate to severe renal 
impairment but no adjustment of the Trobalt dose is recommended in patients with mild renal 
impairment (see section 4.2).  
 
In a single-dose study in healthy volunteers and subjects with end stage renal disease, the retigabine 
AUC was increased by approximately 100% in the subjects with end stage renal disease relative to 
healthy volunteers.  
 
In a second single-dose study in subjects with end stage renal disease receiving chronic haemodialysis 
(n= 8), initiation of dialysis at approximately 4 hours after a single dose of retigabine (100 mg) 
resulted in a median reduction in retigabine plasma concentrations of 52% from the start to end of 
dialysis. The percentage decrease in plasma concentration during dialysis ranged from 34% to 60% 
except for one subject who had a 17% reduction. 
 
Hepatic impairment 
In a single-dose study, there were no clinically significant effects on retigabine AUC in volunteers 
with mild hepatic impairment (Child-Pugh score 5 to 6).  The retigabine AUC was increased by 
approximately 50% in volunteers with moderate hepatic impairment (Child-Pugh score 7 to 9) and by 
approximately 100% in volunteers with severe hepatic impairment (Child-Pugh score >9), relative to 
healthy volunteers. Adjustment of the Trobalt dose is recommended in patients with moderate or 
severe hepatic impairment (see section 4.2). 
 
Body weight 
In a population pharmacokinetic analysis, retigabine clearance increased with increasing body surface 
area. However, this increase is not considered to be clinically meaningful, and since retigabine is 
titrated according to individual patient response and tolerability, dose-adjustments are not required on 
the basis of body weight. 
 
Elderly (65 years of age and above) 
In a single-dose study, retigabine was eliminated more slowly by healthy elderly volunteers 
(66 to 82 years of age) relative to healthy young adult volunteers, resulting in a higher AUC 
(approximately 40 to 50%) and longer terminal half-life (30%) (see section 4.2). 
 

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Gender 
The results of a single-dose study showed that in young adult volunteers, retigabine Cmax was 
approximately 65% higher in females than in males, and in elderly volunteers (66 to 82 years of age), 
retigabine Cmax was approximately 75% higher in females compared with males. When Cmax was 
normalized for weight, the values were approximately 30% higher in young females than in males and 
40% higher in elderly females compared with males. However, there was no apparent gender 
difference in weight-normalized clearance, and since retigabine is titrated according to individual 
patient response and tolerability, dose-adjustments are not required on the basis of gender. 
 
Race 
A post-hoc analysis across multiple healthy volunteer studies demonstrated a 20% reduction in 
retigabine clearance in healthy black volunteers relative to healthy Caucasian volunteers. However, 
this effect is not considered clinically significant, therefore no adjustment of the Trobalt dose is 
recommended. 
 
Paediatric population 
The pharmacokinetics of retigabine in children below 12 years of age have not been investigated. 
 
An open-label, multiple dose pharmacokinetic, safety and tolerability study in five subjects aged 
between 12 years to less than 18 years with partial onset seizures determined that the 
pharmacokinetics of retigabine in adolescents were consistent with the pharmacokinetics of retigabine 
in adults.  However, efficacy and safety of retigabine have not been determined in adolescents. 
 
 
5.3 Preclinical safety data 
 
Maximum doses in repeat dose toxicity studies were limited by the exaggerated pharmacologic effects 
of retigabine (including ataxia, hypokinesia and tremor). At no observed effect levels, animal exposure 
in these studies was generally less than that reached in humans at recommended clinical doses. 
 
Distension of the gall bladder was seen in studies with dogs, but there was no evidence of cholestasis 
or other signs of gall bladder dysfunction, and bile ejection volume was unchanged. The gall bladder 
distension in the dog resulted in focal compression of the liver. No signs of gall bladder dysfunction 
were seen clinically. 
 
Non-clinical data reveal no special hazard for humans based on studies of genotoxicity or carcinogenic 
potential. 
 
Reproductive toxicology 
 
Retigabine had no effect on fertility or general reproductive performance. 
 
In rats, retigabine and/or its metabolites crossed the placenta resulting in tissue concentrations that 
were similar in dams and foetuses. 
 
There was no evidence of teratogenicity following administration of retigabine to pregnant animals 
during the period of organogenesis. In a study of peri- and post-natal development in rats, retigabine 
was associated with increased perinatal mortality following administration during pregnancy. In 
addition, there was a delay in auditory startle response development. These findings were apparent at 
exposure levels lower than those obtained with clinically recommended doses and were accompanied 
by maternal toxicities (including ataxia, hypokinesia, tremor and reduced body weight gain). The 
maternal toxicities interfered with higher dosing of the dams and hence deduction of safety margins 
with regard to human therapy.  
 
 

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6. PHARMACEUTICAL PARTICULARS 
 
6.1 List of excipients 
 
Tablet core 
 
Croscarmellose sodium 
Hypromellose 
Magnesium stearate 
Microcrystalline cellulose. 
 
Film-coating 
 
100 mg tablets: 
Polyvinyl alcohol 
Titanium dioxide (E171) 
Talc (E553b) 
Indigo carmine aluminium lake (E132) 
Iron oxide yellow (E172). 
Lecithin (SOY) 
Xanthan gum 
 
6.2 Incompatibilities 
 
Not applicable. 
 
6.3 Shelf life 
 
3 years. 
 
6.4 Special precautions for storage 
 
This medicinal product does not require any special storage conditions. 
 
6.5 Nature and contents of container 
 
100 mg tablets:  
Opaque PVC-PVDC-aluminium foil blisters. Packs containing 21or 84 film-coated tablets. 
 
Not all pack sizes may be marketed. 
 
6.6 Special precautions for disposal  
 
No special requirements. 
 
 
7. MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,    
TW8 9GS 
United Kingdom 
 
 
 

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8. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/004, EU/1/11/681/005 
 
 
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION 
 
Date of first authorisation: 28 March 2011  
Date of latest renewal: 14 January 2016 
 
 
 
10. DATE OF REVISION OF THE TEXT 
 
 
 
 
Detailed information on this medicinal product is available on the website of the European Medicines 
Agency http://www.ema.europa.eu. 

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1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 200 mg film-coated tablets 
 
 
2. QUALITATIVE AND QUANTITATIVE COMPOSITION 
 
Each film-coated tablet contains 200 mg of retigabine. 
 
For the full list of excipients, see section 6.1. 
 
 
3. PHARMACEUTICAL FORM 
 
Film-coated tablet. 
 
Yellow, oblong, film-coated tablets of 7.1 mm x 14 mm, marked with “RTG-200” on one side.  
 
 
4. CLINICAL PARTICULARS 
 
4.1 Therapeutic indications 
 
Trobalt is indicated as adjunctive treatment of drug-resistant partial onset seizures with or without 
secondary generalization in patients aged 18 years or older with epilepsy, where other appropriate 
combinations with other medicinal products have proved inadequate or have not been tolerated. 
 
4.2 Posology and method of administration 
 
Posology 
 
Trobalt must be titrated, according to individual patient response, in order to optimise the balance 
between efficacy and tolerability. 
 
The maximum total daily starting dose is 300 mg (100 mg three times daily). Thereafter, the total daily 
dose is increased by a maximum of 150 mg every week, according to the individual patient response 
and tolerability. An effective maintenance dose is expected to be between 600 mg/day and 
1,200 mg/day. 
 
The maximum total maintenance dose is 1,200 mg/day. The safety and efficacy of doses higher than 
1,200 mg/day have not been established. 
 
If patients miss one dose or more, it is recommended that they take a single dose as soon as they 
remember. 
 
After taking a missed dose, at least 3 hours should be allowed before the next dose and then the 
normal dosing schedule should be resumed. 
 
When withdrawing Trobalt, the dose must be gradually reduced over a period of at least 3 weeks (see 
section 4.4).  
 
Elderly (65 years of age and above) 
 
There are only limited data on the safety and efficacy of retigabine in patients aged 65 years and 
above. A reduction in the initial and maintenance dose of Trobalt is recommended in elderly patients. 

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The total daily starting dose is 150 mg/day and during the titration period the total daily dose should 
be increased by a maximum of 150 mg every week, according to the individual patient response and 
tolerability. Doses greater than 900 mg/day are not recommended (see sections 4.4 and 5.2). 
 
Renal impairment 
 
Retigabine and its metabolites are eliminated principally by renal excretion. 
 
No dose adjustment is required in patients with mild renal impairment (creatinine clearance 50 to 
80 ml/min; see section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe renal impairment (creatinine clearance <50 ml/min; see section 5.2). The total 
daily starting dose is 150 mg, and it is recommended that during the titration period, the total daily 
dose is increased by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
For patients with end-stage renal disease receiving haemodialysis, the three daily doses should be 
taken as usual on the dialysis day. In addition, a single supplemental dose is recommended 
immediately after haemodialysis. If breakthrough seizures occur towards the end of dialysis then an 
additional supplemental dose may be considered at the start of subsequent dialysis sessions. 
 
Hepatic impairment 
 
No dose reduction is required in patients with mild hepatic impairment (Child-Pugh score 5 to 6; see 
section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe hepatic impairment (Child-Pugh score ≥7; see section 5.2). The total daily starting 
dose is 150 mg, and it is recommended that during the titration period, the total daily dose is increased 
by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
Paediatric population 
 
The safety and efficacy of retigabine in children below 18 years of age has not yet been established 
(see section 5.2). Currently available pharmacokinetic data are described in section 5.2, but no 
recommendation on a posology can be made. 
 
 
Method of administration 
 
Trobalt is for oral use. The tablets must be taken in three divided doses each day.  The tablets should 
be swallowed whole, and not chewed, crushed or divided. 
 
Trobalt may be taken with or without food (see section 5.2). 
 
4.3 Contraindications 
 
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1. 
 
4.4 Special warnings and precautions for use 
 
Eye disorders 
 
Pigment changes (discolouration) of ocular tissues, including the retina have been reported in long-
term clinical studies withretigabine, sometimes but not always in conjunction with pigment changes of 
the skin, lips or nails (see below paragraph and section 4.8). Reversibility of retinal pigmentation after 

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retigabine discontinuation has been reported in some subjects. The long-term prognosis of these 
findings is currently unknown, but some of the reports have been associated with visual impairment. 
 
In addition a distinct form of macular abnormality with features of vitelliform maculopathy (see 
section 4.8) has also been identified, in most cases diagnosed with optical coherence tomography 
(OCT) imaging. The rate of progression of vitelliform maculopathy and its impact on retinal and 
macular function and vision is unclear. Vision abnormalities (field constriction, loss of central 
sensitivity, and reduced visual acuity) have been reported.  
 
All patients should undergo comprehensive ophthalmological examinations at baseline and at least 
every six months, which should include visual acuity, slit-lamp examination, dilated fundus 
photography, and macular OCT imaging. If retinal pigment changes, vitelliform maculopathy or vision 
changes are detected, treatment with Trobalt should only be continued after a careful re-assessment of 
the balance of benefits and risks. If continued, the patient should be monitored more closely. 
 
Skin disorders 
 
Pigment changes (discolouration) of the skin, lips or nails have been reported in long-term clinical 
studies with retigabine, sometimes but not always in conjunction with pigment changes of ocular 
tissues (see above paragraph and section 4.8). In patients who develop these changes, treatment with 
Trobalt should only be continued after a careful re-assessment  of the balance of benefits and risks. 
 
Urinary retention 
 
Urinary retention, dysuria and urinary hesitation were reported in controlled clinical studies with 
retigabine, generally within the first 8 weeks of treatment (see section 4.8). Trobalt must be used with 
caution in patients at risk of urinary retention, and it is recommended that patients are advised about 
the risk of these possible effects. 
 
QT interval 
 
A study of cardiac conduction in healthy subjects has demonstrated that retigabine titrated to 1,200 
mg/day produced a QT-prolonging effect. A mean increase in Individual Corrected QT Interval (QTcI) 
of up to 6.7 ms (upper bound of 95% one-sided CI 12.6 ms) was observed within 3 hours of dosing. 
Caution should be taken when Trobalt is prescribed with medicinal products known to increase 
QT interval and in patients with known prolonged QT interval, congestive cardiac failure, ventricular 
hypertrophy, hypokalaemia or hypomagnesaemia and in patients initiating treatment who are 65 years 
of age and above. 
 
In these patients it is recommended that an electrocardiogram (ECG) is recorded before initiation of 
treatment with Trobalt and in those with a corrected QT interval >440ms at baseline, an ECG should 
be recorded on reaching the maintenance dose. 
 
Psychiatric disorders 
 
Confusional state, psychotic disorders and hallucinations were reported in controlled clinical studies 
with retigabine (see section 4.8).  These effects generally occurred within the first 8 weeks of 
treatment, and frequently led to treatment withdrawal in affected patients. It is recommended that 
patients are advised about the risk of these possible effects. 
 

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Suicide risk 
 
Suicidal ideation and behaviour have been reported in patients treated with antiepileptic agents in 
several indications. A meta-analysis of randomised placebo-controlled trials of antiepileptic medicinal 
products has also shown a small increased risk of suicidal ideation and behaviour. The mechanism of 
this risk is not known and the available data do not exclude the possibility of an increased risk for 
retigabine. 
 
Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate 
treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical 
advice if signs of suicidal ideation or behaviour emerge. 
 
Elderly (65 years of age and above) 
 
Elderly patients may be at increased risk of central nervous system events, urinary retention and atrial 
fibrillation.  Trobalt must be used with caution in this population and a reduced initial and 
maintenance dose is recommended (see sections 4.2 and 5.2). 
 
Withdrawal seizures 
 
Trobalt must be withdrawn gradually to minimise the potential for rebound seizures.  It is 
recommended that the Trobalt dose is reduced over a period of at least 3 weeks, unless safety concerns 
require an abrupt withdrawal (see section 4.2). 
 
Laboratory tests 
 
Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine 
bilirubin, which can result in falsely elevated readings. 
 
 
4.5 Interaction with other medicinal products and other forms of interaction 
 
Interaction studies have only been performed in adults. 
 
Other antiepileptic medicinal products 
 
In vitro data indicated a low potential for interaction with other antiepileptic medicinal products (see 
section 5.2).  The drug interaction potential was, therefore, evaluated based on a pooled analysis 
across clinical studies and whilst not considered as robust as stand-alone clinical interaction studies, 
the results support the in vitro data. 
 
Based on these pooled data, retigabine did not cause clinically significant effects on the plasma trough 
concentrations of the following antiepileptic medicinal products: 
- carbamazepine, clobazam, clonazepam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 

phenobarbital, phenytoin, pregabalin, topiramate, valproate, zonisamide. 
 
Further, based on pooled data, there were no clinically significant effects of the following antiepileptic 
medicinal products on retigabine pharmacokinetics: 
- lamotrigine, levetiracetam, oxcarbazepine, topiramate, valproate.   
 
This analysis also showed no clinically significant effect of the inducers (phenytoin, carbamazepine 
and phenobarbital) on retigabine clearance. 
 
However, steady-state data from a limited number of patients in smaller phase II studies indicated that:  
-  phenytoin can reduce retigabine systemic exposure by 35% 
-  carbamazepine can reduce retigabine systemic exposure by 33% 

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Interaction with digoxin 
 
Data from an in vitro study showed that the N-acetyl metabolite of retigabine (NAMR) inhibited 
P-glycoprotein-mediated transport of digoxin in a concentration-dependent manner.  
 
Based on a study conducted in healthy volunteers, therapeutic doses of retigabine (600-1,200 mg/day) 
resulted in a minor (8-18%) increase in digoxin AUC following a single oral dose of digoxin. The 
increase did not appear to be dependent on retigabine dose and is not considered clinically relevant. 
There was no meaningful change in digoxin Cmax. No dose adjustment of digoxin is needed. 
 
Interaction with anaesthetics 
 
Trobalt may increase the duration of anaesthesia induced by some anaesthetics (for example thiopental 
sodium; see section 5.1). 
 
Interaction with alcohol 
 
Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual 
blurring in healthy volunteers. It is recommended that patients are advised about the possible effects 
on vision if they take Trobalt with alcohol. 
 
Oral contraceptives 
 
At retigabine doses of up to 750 mg/day, there was no clinically significant effect of retigabine on the 
pharmacokinetics of the estrogen (ethinyl estradiol) or progestogen (norethindrone) components of the 
oral contraceptive pill. In addition, there was no clinically significant effect of the low dose 
combination oral contraceptive pill on the pharmacokinetics of retigabine. 
 
 
4.6 Fertility, pregnancy and lactation 
 
Pregnancy 
 
Risk related to antiepileptic medicinal products in general 
Specialist advice should be given to women who are of childbearing potential. The need for treatment 
with antiepileptic medicinal products should be reviewed when a woman is planning to become 
pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic medicine 
therapy should be avoided as this may lead to breakthrough seizures that could have serious 
consequences for the woman and the unborn child.  
 
The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers 
treated with antiepileptic medicinal products compared with the expected incidence in the general 
population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular 
malformations and neural tube defects. Therapy with multiple antiepileptic medicinal products is 
associated with a higher risk of congenital malformations than monotherapy and therefore 
monotherapy should be used whenever possible. 
 
Risk related to Trobalt 
There are no adequate data from the use of retigabine in pregnant women. Animal studies are 
insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies 
were less than those reached in humans at recommended doses (see section 5.3). In a developmental 
study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in 
auditory startle response development of the offspring (see section 5.3). The clinical significance of 
this finding is not known.  
 

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Trobalt is not recommended during pregnancy and in women of childbearing age, not using 
contraception. 
 
Breastfeeding 
 
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown 
excretion of retagabine and/or its metabolites in breast milk. A decision on whether to 
continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made 
taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the 
woman. 
 
Fertility 
 
There were no treatment-related effects of retigabine on fertility in animal studies. However, the 
plasma levels achieved in these studies were less than those reached in humans at recommended doses 
(see section 5.3). 
 
The effect of retigabine on human fertility has not been established. 
 
4.7 Effects on ability to drive and use machines 
 
Adverse reactions such as dizziness, somnolence, diplopia and blurred vision were reported in 
controlled clinical studies, particularly during titration (see section 4.8). It is recommended that 
patients are advised about the risk of such adverse reactions at treatment initiation and following each 
titration step, and that they are advised not to drive or operate machinery until they have established 
how Trobalt affects them. 
 
4.8 Undesirable effects 
 
Summary of the safety profile 
 
In pooled safety data from three multicentre, randomised, double-blind, placebo-controlled studies, 
adverse reactions were generally mild to moderate in intensity, and were most commonly reported in 
the first 8 weeks of treatment. There was an apparent dose-relationship for dizziness, somnolence, 
confusional state, aphasia, coordination abnormal, tremor, balance disorder, memory impairment, gait 
disturbance, blurred vision and constipation. 
 
Adverse reactions that were most frequently reported to lead to discontinuation were dizziness, 
somnolence, fatigue and confusional state. 
 
Tabulated list of adverse reactions 
 
The following convention has been used for the classification of adverse reactions: 
 
Very common: ≥1/10 
Common:  ≥1/100 to <1/10 
Uncommon:  ≥1/1,000 to <1/100 
Rare: ≥1/10,000 to <1/1,000 
Very rare: <1/10,000. 
 

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Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. 
 
System Organ 
Class 
 

Very common Common Uncommon 

Metabolism and 
nutrition disorders 
 

 Weight increased 
Increased appetite 

 

Psychiatric 
disorders 
 

 Confusional state 
Psychotic disorders 
Hallucinations 
Disorientation 
Anxiety 
 

 

Nervous system 
disorders 
 

Dizziness 
Somnolence 
 

Amnesia 
Aphasia 
Coordination abnormal 
Vertigo 
Paraesthesia 
Tremor 
Balance disorder 
Memory impairment 
Dysphasia 
Dysarthria 
Disturbance in attention 
Gait disturbance 
Myoclonus 
 

Hypokinesia 

Eye disorders 
 

Pigment changes 
(discolouration) 
of ocular tissues, 
including the 
retina, have been 
observed after 
several years of 
treatment. Some 
of these reports 
have been 
associated with 
visual 
impairment. 
 

Diplopia 
Blurred vision 
Acquired Vitelliform 
Maculopathy 
 

 

Gastrointestinal 
disorders 

 Nausea 
Constipation 
Dyspepsia 
Dry mouth 
 

Dysphagia 

Hepatobiliary 
disorders 

 Increased liver function 
tests 
 

 
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System Organ 
Class 
 

Very common Common Uncommon 

Skin and 
subcutaneous 
disorders 
 

Blue-grey 
discolouration of 
the nails, lips 
and/or skin have 
been observed, 
generally at 
higher doses and 
after several years 
of treatment. 
 

 Skin rash 
Hyperhidrosis 

Renal and urinary 
disorders 
 

 Dysuria 
Urinary hesitation 
Haematuria 
Chromaturia 
 

Urinary retention 
Nephrolithiasis 

General disorders 
and administrative 
site conditions 

Fatigue Asthenia 
Malaise  
Peripheral oedema 
 

 

 
Description of selected adverse reactions 
Adverse reactions related to voiding dysfunction, including urinary retention, were reported in 5% of 
retigabine-treated patients in the pooled safety dataset (see section 4.4). The majority of events 
occurred in the first 8 weeks of treatment, and there was no apparent dose-relationship. 
 
In retigabine-treated patients in the pooled dataset, confusional state was reported in 9% of patients, 
hallucinations in 2% of patients and psychotic disorders in 1% of patients (see section 4.4). The 
majority of adverse reactions occurred in the first 8 weeks of treatment, and there was an apparent 
dose-relationship for confusional state only. 
 
Adverse event data from clinical trial subjects showed a rate of event of discolouration of the nails, 
lips, skin and/or mucosa per patient year of exposure of 3.6%. The cumulative incidences of an event 
at 1 year, 2 years, 3 years, 4 years and 5 years of exposure are approximately 1%, 1.8%, 4.4%, 10.2% 
and 16.7% respectively. 
 
Approximately 30-40% of clinical trial subjects who were being treated with retigabine and underwent 
a skin and/or ophthalmological examination had findings of discolouration of nails, lips, skin and/or 
mucosa or non-retinal ocular pigmentation, and approximately 15-30% of clinical trial subjects who 
were being treated with retigabine and underwent an ophthalmological examination had retinal 
pigmentation findings. In addition, cases of acquired vitelliform-type maculopathy have been 
identified, both in clinical studies and as spontaneous reports. 
 
Data from elderly patients indicates that they may be more likely to experience certain central nervous 
system events, including somnolence, amnesia, coordination abnormal, vertigo, tremor, balance 
disorder, memory impairment and gait disturbance. 
 
Reporting of suspected adverse reactions  
 
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It 
allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare 
professionals are asked to report any suspected adverse reactions via the national reporting system 
listed in Appendix V. 
 

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4.9 Overdose 
 
Symptoms and signs 
 
There is limited experience of overdose with retigabine. 
 
Retigabine overdoses in excess of 2,500 mg/day were reported during clinical studies. In addition to 
adverse reactions seen at therapeutic doses, symptoms of retigabine overdose included agitation, 
aggressive behaviour and irritability. There were no reported sequelae. 
 
In a study in volunteers, cardiac arrhythmia (cardiac arrest/asystole or ventricular tachycardia) 
occurred in two subjects within 3 hours of receiving a single 900 mg retigabine dose. The arrhythmias 
spontaneously resolved, and both volunteers recovered without sequelae. 
 
Management 
 
In the event of overdose, it is recommended that the patient is given appropriate supportive therapy as 
clinically indicated, including electrocardiogram (ECG) monitoring. Further management should be as 
recommended by the national poisons centre, where available. 
 
Haemodialysis has been shown to reduce the plasma concentrations of retigabine and NAMR by 
approximately 50%. 
 
 
5. PHARMACOLOGICAL PROPERTIES 
 
5.1  Pharmacodynamic properties 
 
Pharmacotherapeutic group: antiepileptics, other antiepileptics, ATC code: N03AX21. 
 
Mechanism of action 
 
Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are 
important determinants of neuronal activity. In vitro studies indicate that retigabine acts primarily 
through opening neuronal potassium channels (KCNQ2 [Kv7.2] and KCNQ3 [Kv7.3]). This stabilises 
the resting membrane potential and controls the sub-threshold electrical excitability in neurons, thus 
preventing the initiation of epileptiform action potential bursts. Mutations in the KCNQ channels 
underlie several human inheritable disorders, including epilepsy (KCNQ2 and 3). The mechanism of 
action of retigabine on potassium channels has been well documented, however other mechanisms by 
which retigabine may assert an antiepileptic effect have yet to be fully elucidated. 
 
In a range of seizure models, retigabine increased the threshold for seizure induction produced by 
maximal electroshock, pentylenetetrazol, picrotoxin and N-methyl-D-aspartate (NMDA). Retigabine 
also displayed inhibitory properties in multiple kindling models, for example, in the fully kindled state 
and in some cases during the kindling development. In addition, retigabine was effective in preventing 
status epilepticus seizures in rodents with cobalt-induced epileptogenic lesions, and inhibiting tonic 
extensor seizures in genetically susceptible mice. The relevance of these models to human epilepsy, 
however, is not known. 
 
Pharmacodynamic effects 
 
In rats, retigabine increased the sleep time induced by thiopental sodium from approximately 4 min to 
53 min, and the propofol-induced sleep time from approximately 8 min to 12 min. There was no effect 
on sleep time induced by halothane or methohexital sodium. Retigabine may increase the duration of 
anaesthesia induced by some anaesthetics (for example thiopental sodium). 
 

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Clinical efficacy of adjunctive retigabine therapy in partial onset seizures 
 
Three multicentre, randomized, double-blind, placebo-controlled studies in a total of 1239 adult 
patients have been conducted to assess the efficacy of retigabine as adjunctive therapy of partial onset 
seizures, with or without secondary generalisation. All patients enrolled were to have had seizures that 
were not adequately controlled with 1 to 3 concomitant antiepileptic medicinal products, and more 
than 75% of all patients were taking ≥2 concurrent antiepileptic medicinal products. Across all studies, 
patients had a mean duration of epilepsy of 22 years and a median baseline seizure frequency ranging 
from 8 to 12 per 28 days. Patients were randomized to placebo or retigabine at 600, 900 or 
1,200 mg/day (see Table 1). During an 8-week baseline period, patients had to experience ≥4 partial 
onset seizures per 28 days. Patients could not be seizure-free for ≥21 days. The duration of the 
maintenance phase was 8 or 12 weeks. 
 
The primary efficacy endpoints were: 
- percentage change in the 28-day total partial seizure frequency from baseline to the 

double-blind phase (titration and maintenance phases combined) in all three studies 
- responder rate (defined as the percentage of patients with a ≥50% reduction in 28-day total 

partial seizure frequency) from baseline to the maintenance phase (Studies 301 and 302 only). 
 
Retigabine was effective in adjunctive treatment of adults with partial onset seizures in three clinical 
studies (Table 1).  Retigabine was statistically significantly superior to placebo at 600 mg/day 
(one study), 900 mg/day (two studies) and 1,200 mg/day (two studies). 
 
The studies were not designed to evaluate specific combinations of antiepileptic medicinal products. 
Consequently, the efficacy and safety of retigabine when taken concomitantly with antiepileptic 
medicinal products that were less commonly used as background treatment in the clinical studies, 
including levetiracetam, has not been definitely shown. 
 
Table 1. Summary of percentage changes in 28-day total partial seizure frequency and responder 
rates 
 
Study  
(n=population in double-blind phase;  
n=population in maintenance phase) 
 

Placebo Retigabine 
600 

mg/day 
900 

mg/day 
1,200 

mg/day 

Study 205 (n=396; n=303) 
Total partial seizure frequency (median) % change  -13% -23% -29%* -35%* 
Responder rate (secondary endpoint) 
 

26% 28% 41% 41%* 

Study 301 (n=305; n=256) 
Total partial seizure frequency (median) % change -18% ~ ~ -44%* 
Responder rate  
 

23% ~ ~ 56%* 

Study 302 (n=538; n=471) 
Total partial seizure frequency (median) % change -16% -28%* -40%* ~ 
Responder rate  
 

19% 39%* 47%* ~ 

* Statistically significant, p≤0.05 
~ Dose not studied 
 
In open-label extensions of the three placebo-controlled studies, persistence of efficacy was 
maintained over an evaluation period of at least 12 months (365 patients). 
 

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Paediatric population 
 
The European Medicines Agency has waived the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 0 to below 2 years with Lennox Gastaut Syndrome (see section 4.2 
for information on paediatric use). 
 
The European Medicines Agency has deferred the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 2 to below 18 years with Lennox Gastaut Syndrome, and in 
paediatric patients aged 0 to below 18 years with partial onset seizures (see section 4.2 for information 
on paediatric use). 
 
5.2 Pharmacokinetic properties 
 
Absorption 
 
After both single and multiple oral doses, retigabine is rapidly absorbed with median tmax values 
generally between 0.5 and 2 hours. Absolute oral bioavailability of retigabine relative to an 
intravenous dose is approximately 60%. 
 
Administration of retigabine with a high fat meal resulted in no change in the overall extent of 
retigabine absorption, but food reduced the between-subject variability in Cmax (23%) compared to the 
fasted state (41%), and led to an increase in Cmax (38%).  The effect of food on Cmax under usual 
clinical conditions is not expected to be clinically relevant.  Therefore Trobalt may be taken with or 
without food.  
 
Distribution 
 
Retigabine is approximately 80% bound to plasma protein over the concentration range of 0.1 to 
2 µg/ml. The steady state volume of distribution of retigabine is 2 to 3 l/kg following intravenous 
dosing. 
 
Biotransformation 
 
Retigabine is extensively metabolised in humans. A substantial fraction of the retigabine dose is 
converted to inactive N-glucuronides. Retigabine is also metabolised to an N-acetyl metabolite 
(NAMR) that is also subsequently glucuronidated. NAMR has antiepileptic activity, but is less potent 
than retigabine in animal seizure models. 
 
There is no evidence for hepatic oxidative metabolism of retigabine or NAMR by cytochrome P450 
enzymes.  Therefore, co-administration with inhibitors or inducers of cytochrome P450 enzymes is 
unlikely to affect the pharmacokinetics of retigabine or NAMR. 
 
In vitro studies using human liver microsomes showed little or no potential for retigabine to inhibit the 
major cytochrome P450 isoenzymes (including CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, 
CYP2D6, CYP2E1 and CYP3A4/5).  In addition, retigabine and NAMR did not induce CYP1A2 or 
CYP3A4/5 in human primary hepatocytes. Therefore, retigabine is unlikely to affect the 
pharmacokinetics of substrates of the major cytochrome P450 isoenzymes through inhibition or 
induction mechanisms. 
 

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Elimination 
 
Elimination of retigabine occurs via a combination of hepatic metabolism and renal excretion. A total 
of approximately 84% of the dose is recovered in the urine, including the N-acetyl metabolite (18%), 
N-glucuronides of the parent active substance and of the N-acetyl metabolite (24%), or parent active 
substance (36%). Only 14% of retigabine is excreted in the faeces. Retigabine has a plasma half-life of 
approximately 6 to 10 hours. The total clearance of retigabine from plasma following intravenous 
dosing is typically 0.4 to 0.6 l/h/kg. 
 
Linearity 
 
Retigabine pharmacokinetics are essentially linear over the single-dose range of 25 to 600 mg in 
healthy volunteers and up to 1,200 mg daily in patients with epilepsy, with no unexpected 
accumulation following repeated administration. 
 
Special patient populations 
 
Renal impairment 
In a single-dose study, retigabine AUC was increased by approximately 30% in volunteers with mild 
renal impairment (creatinine clearance 50 to 80 ml/min) and by approximately 100% in volunteers 
with moderate to severe renal impairment (creatinine clearance <50 ml/min), relative to healthy 
volunteers.  Adjustment of the Trobalt dose is recommended in patients with moderate to severe renal 
impairment but no adjustment of the Trobalt dose is recommended in patients with mild renal 
impairment (see section 4.2).  
 
In a single-dose study in healthy volunteers and subjects with end stage renal disease, the retigabine 
AUC was increased by approximately 100% in the subjects with end stage renal disease relative to 
healthy volunteers.  
 
In a second single-dose study in subjects with end stage renal disease receiving chronic haemodialysis 
(n= 8), initiation of dialysis at approximately 4 hours after a single dose of retigabine (100 mg) 
resulted in a median reduction in retigabine plasma concentrations of 52% from the start to end of 
dialysis. The percentage decrease in plasma concentration during dialysis ranged from 34% to 60% 
except for one subject who had a 17% reduction. 
 
Hepatic impairment 
In a single-dose study, there were no clinically significant effects on retigabine AUC in volunteers 
with mild hepatic impairment (Child-Pugh score 5 to 6).  The retigabine AUC was increased by 
approximately 50% in volunteers with moderate hepatic impairment (Child-Pugh score 7 to 9) and by 
approximately 100% in volunteers with severe hepatic impairment (Child-Pugh score >9), relative to 
healthy volunteers. Adjustment of the Trobalt dose is recommended in patients with moderate or 
severe hepatic impairment (see section 4.2). 
 
Body weight 
In a population pharmacokinetic analysis, retigabine clearance increased with increasing body surface 
area. However, this increase is not considered to be clinically meaningful, and since retigabine is 
titrated according to individual patient response and tolerability, dose-adjustments are not required on 
the basis of body weight. 
 
Elderly (65 years of age and above) 
In a single-dose study, retigabine was eliminated more slowly by healthy elderly volunteers 
(66 to 82 years of age) relative to healthy young adult volunteers, resulting in a higher AUC 
(approximately 40 to 50%) and longer terminal half-life (30%) (see section 4.2). 
 

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Gender 
The results of a single-dose study showed that in young adult volunteers, retigabine Cmax was 
approximately 65% higher in females than in males, and in elderly volunteers (66 to 82 years of age), 
retigabine Cmax was approximately 75% higher in females compared with males. When Cmax was 
normalized for weight, the values were approximately 30% higher in young females than in males and 
40% higher in elderly females compared with males. However, there was no apparent gender 
difference in weight-normalized clearance, and since retigabine is titrated according to individual 
patient response and tolerability, dose-adjustments are not required on the basis of gender. 
 
Race 
A post-hoc analysis across multiple healthy volunteer studies demonstrated a 20% reduction in 
retigabine clearance in healthy black volunteers relative to healthy Caucasian volunteers. However, 
this effect is not considered clinically significant, therefore no adjustment of the Trobalt dose is 
recommended. 
 
Paediatric population 
The pharmacokinetics of retigabine in children below 12 years of age have not been investigated. 
 
An open-label, multiple dose pharmacokinetic, safety and tolerability study in five subjects aged 
between 12 years to less than 18 years with partial onset seizures determined that the 
pharmacokinetics of retigabine in adolescents were consistent with the pharmacokinetics of retigabine 
in adults.  However, efficacy and safety of retigabine have not been determined in adolescents. 
 
 
5.3 Preclinical safety data 
 
Maximum doses in repeat dose toxicity studies were limited by the exaggerated pharmacologic effects 
of retigabine (including ataxia, hypokinesia and tremor). At no observed effect levels, animal exposure 
in these studies was generally less than that reached in humans at recommended clinical doses. 
 
Distension of the gall bladder was seen in studies with dogs, but there was no evidence of cholestasis 
or other signs of gall bladder dysfunction, and bile ejection volume was unchanged. The gall bladder 
distension in the dog resulted in focal compression of the liver. No signs of gall bladder dysfunction 
were seen clinically. 
 
Non-clinical data reveal no special hazard for humans based on studies of genotoxicity or carcinogenic 
potential. 
 
Reproductive toxicology 
 
Retigabine had no effect on fertility or general reproductive performance. 
 
In rats, retigabine and/or its metabolites crossed the placenta resulting in tissue concentrations that 
were similar in dams and foetuses. 
 
There was no evidence of teratogenicity following administration of retigabine to pregnant animals 
during the period of organogenesis. In a study of peri- and post-natal development in rats, retigabine 
was associated with increased perinatal mortality following administration during pregnancy. In 
addition, there was a delay in auditory startle response development. These findings were apparent at 
exposure levels lower than those obtained with clinically recommended doses and were accompanied 
by maternal toxicities (including ataxia, hypokinesia, tremor and reduced body weight gain). The 
maternal toxicities interfered with higher dosing of the dams and hence deduction of safety margins 
with regard to human therapy.  
 
 

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6. PHARMACEUTICAL PARTICULARS 
 
6.1 List of excipients 
 
Tablet core 
 
Croscarmellose sodium 
Hypromellose 
Magnesium stearate 
Microcrystalline cellulose. 
 
Film-coating 
 
200 mg tablets: 
Polyvinyl alcohol 
Titanium dioxide (E171) 
Talc (E553b) 
Iron oxide yellow (E172). 
Lecithin (SOY) 
Xanthan gum 
 
 
6.2 Incompatibilities 
 
Not applicable. 
 
6.3 Shelf life 
 
3 years. 
 
6.4 Special precautions for storage 
 
This medicinal product does not require any special storage conditions. 
 
6.5 Nature and contents of container 
 
200 mg tablets: 
Opaque PVC-PVDC-aluminium foil blisters. Pack containing 84 film-coated tablets; multi-pack 
comprising 168 (2 x 84) film-coated tablets. 
 
Not all pack sizes may be marketed. 
 
6.6 Special precautions for disposal  
 
No special requirements. 
 
 
7. MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 

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8. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/007, EU/1/11/681/008 
 
 
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION 
 
Date of first authorisation: 28 March 2011  
Date of latest renewal: 14 January 2016 
 
10. DATE OF REVISION OF THE TEXT 
 
 
 
 
Detailed information on this medicinal product is available on the website of the European Medicines 
Agency http://www.ema.europa.eu. 

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1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 300 mg film-coated tablets 
 
 
2. QUALITATIVE AND QUANTITATIVE COMPOSITION 
 
Each film-coated tablet contains 300 mg of retigabine. 
 
For the full list of excipients, see section 6.1. 
 
 
3. PHARMACEUTICAL FORM 
 
Film-coated tablet. 
 
Green, oblong, film-coated tablets of 7.1 mm x 16 mm, marked with “RTG-300” on one side.  
 
 
4. CLINICAL PARTICULARS 
 
4.1 Therapeutic indications 
 
Trobalt is indicated as adjunctive treatment of drug-resistant partial onset seizures with or without 
secondary generalization in patients aged 18 years or older with epilepsy, where other appropriate 
combinations with other medicinal products have proved inadequate or have not been tolerated. 
 
4.2 Posology and method of administration 
 
Posology 
 
Trobalt must be titrated, according to individual patient response, in order to optimise the balance 
between efficacy and tolerability. 
 
The maximum total daily starting dose is 300 mg (100 mg three times daily). Thereafter, the total daily 
dose is increased by a maximum of 150 mg every week, according to the individual patient response 
and tolerability. An effective maintenance dose is expected to be between 600 mg/day and 
1,200 mg/day. 
 
The maximum total maintenance dose is 1,200 mg/day. The safety and efficacy of doses higher than 
1,200 mg/day have not been established. 
 
If patients miss one dose or more, it is recommended that they take a single dose as soon as they 
remember. 
 
After taking a missed dose, at least 3 hours should be allowed before the next dose and then the 
normal dosing schedule should be resumed. 
 
When withdrawing Trobalt, the dose must be gradually reduced over a period of at least 3 weeks (see 
section 4.4).  
 
Elderly (65 years of age and above) 
 
There are only limited data on the safety and efficacy of retigabine in patients aged 65 years and 
above. A reduction in the initial and maintenance dose of Trobalt is recommended in elderly patients. 

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The total daily starting dose is 150 mg/day and during the titration period the total daily dose should 
be increased by a maximum of 150 mg every week, according to the individual patient response and 
tolerability. Doses greater than 900 mg/day are not recommended (see sections 4.4 and 5.2). 
 
Renal impairment 
 
Retigabine and its metabolites are eliminated principally by renal excretion. 
 
No dose adjustment is required in patients with mild renal impairment (creatinine clearance 50 to 
80 ml/min; see section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe renal impairment (creatinine clearance <50 ml/min; see section 5.2). The total 
daily starting dose is 150 mg, and it is recommended that during the titration period, the total daily 
dose is increased by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
For patients with end-stage renal disease receiving haemodialysis, the three daily doses should be 
taken as usual on the dialysis day. In addition, a single supplemental dose is recommended 
immediately after haemodialysis. If breakthrough seizures occur towards the end of dialysis then an 
additional supplemental dose may be considered at the start of subsequent dialysis sessions. 
 
Hepatic impairment 
 
No dose reduction is required in patients with mild hepatic impairment (Child-Pugh score 5 to 6; see 
section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe hepatic impairment (Child-Pugh score ≥7; see section 5.2). The total daily starting 
dose is 150 mg, and it is recommended that during the titration period, the total daily dose is increased 
by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
Paediatric population 
 
The safety and efficacy of retigabine in children below 18 years of age has not yet been established 
(see section 5.2). Currently available pharmacokinetic data are described in section 5.2, but no 
recommendation on a posology can be made. 
 
 
Method of administration 
 
Trobalt is for oral use. The tablets must be taken in three divided doses each day.  The tablets should 
be swallowed whole, and not chewed, crushed or divided. 
 
Trobalt may be taken with or without food (see section 5.2). 
 
4.3 Contraindications 
 
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1. 
 
4.4 Special warnings and precautions for use 
 
Eye disorders 
 
Pigment changes (discolouration) of ocular tissues, including the retina have been reported in long-
term clinical studies withretigabine, sometimes but not always in conjunction with pigment changes of 
the skin, lips or nails (see below paragraph and section 4.8). Reversibility of retinal pigmentation after 

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retigabine discontinuation has been reported in some subjects. The long-term prognosis of these 
findings is currently unknown, but some of the reports have been associated with visual impairment. 
 
In addition a distinct form of macular abnormality with features of vitelliform maculopathy (see 
section 4.8) has also been identified, in most cases diagnosed with optical coherence tomography 
(OCT) imaging. The rate of progression of vitelliform maculopathy and its impact on retinal and 
macular function and vision is unclear. Vision abnormalities (field constriction, loss of central 
sensitivity, and reduced visual acuity) have been reported.  
 
All patients should undergo comprehensive ophthalmological examinations at baseline and at least 
every six months, which should include visual acuity, slit-lamp examination, dilated fundus 
photography, and macular OCT imaging. If retinal pigment changes, vitelliform maculopathy or vision 
changes are detected, treatment with Trobalt should only be continued after a careful re-assessment of 
the balance of benefits and risks. If continued, the patient should be monitored more closely. 
 
Skin disorders 
 
Pigment changes (discolouration) of the skin, lips or nails have been reported in long-term clinical 
studies with retigabine, sometimes but not always in conjunction with pigment changes of ocular 
tissues (see above paragraph and section 4.8). In patients who develop these changes, treatment with 
Trobalt should only be continued after a careful re-assessment  of the balance of benefits and risks. 
 
Urinary retention 
 
Urinary retention, dysuria and urinary hesitation were reported in controlled clinical studies with 
retigabine, generally within the first 8 weeks of treatment (see section 4.8). Trobalt must be used with 
caution in patients at risk of urinary retention, and it is recommended that patients are advised about 
the risk of these possible effects. 
 
QT interval 
 
A study of cardiac conduction in healthy subjects has demonstrated that retigabine titrated to 1,200 
mg/day produced a QT-prolonging effect. A mean increase in Individual Corrected QT Interval (QTcI) 
of up to 6.7 ms (upper bound of 95% one-sided CI 12.6 ms) was observed within 3 hours of dosing. 
Caution should be taken when Trobalt is prescribed with medicinal products known to increase 
QT interval and in patients with known prolonged QT interval, congestive cardiac failure, ventricular 
hypertrophy, hypokalaemia or hypomagnesaemia and in patients initiating treatment who are 65 years 
of age and above. 
 
In these patients it is recommended that an electrocardiogram (ECG) is recorded before initiation of 
treatment with Trobalt and in those with a corrected QT interval >440ms at baseline, an ECG should 
be recorded on reaching the maintenance dose. 
 
Psychiatric disorders 
 
Confusional state, psychotic disorders and hallucinations were reported in controlled clinical studies 
with retigabine (see section 4.8).  These effects generally occurred within the first 8 weeks of 
treatment, and frequently led to treatment withdrawal in affected patients. It is recommended that 
patients are advised about the risk of these possible effects. 
 

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Suicide risk 
 
Suicidal ideation and behaviour have been reported in patients treated with antiepileptic agents in 
several indications. A meta-analysis of randomised placebo-controlled trials of antiepileptic medicinal 
products has also shown a small increased risk of suicidal ideation and behaviour. The mechanism of 
this risk is not known and the available data do not exclude the possibility of an increased risk for 
retigabine. 
 
Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate 
treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical 
advice if signs of suicidal ideation or behaviour emerge. 
 
Elderly (65 years of age and above) 
 
Elderly patients may be at increased risk of central nervous system events, urinary retention and atrial 
fibrillation.  Trobalt must be used with caution in this population and a reduced initial and 
maintenance dose is recommended (see sections 4.2 and 5.2). 
 
Withdrawal seizures 
 
Trobalt must be withdrawn gradually to minimise the potential for rebound seizures.  It is 
recommended that the Trobalt dose is reduced over a period of at least 3 weeks, unless safety concerns 
require an abrupt withdrawal (see section 4.2). 
 
Laboratory tests 
 
Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine 
bilirubin, which can result in falsely elevated readings. 
 
 
4.5 Interaction with other medicinal products and other forms of interaction 
 
Interaction studies have only been performed in adults. 
 
Other antiepileptic medicinal products 
 
In vitro data indicated a low potential for interaction with other antiepileptic medicinal products (see 
section 5.2).  The drug interaction potential was, therefore, evaluated based on a pooled analysis 
across clinical studies and whilst not considered as robust as stand-alone clinical interaction studies, 
the results support the in vitro data. 
 
Based on these pooled data, retigabine did not cause clinically significant effects on the plasma trough 
concentrations of the following antiepileptic medicinal products: 
- carbamazepine, clobazam, clonazepam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 

phenobarbital, phenytoin, pregabalin, topiramate, valproate, zonisamide. 
 
Further, based on pooled data, there were no clinically significant effects of the following antiepileptic 
medicinal products on retigabine pharmacokinetics: 
- lamotrigine, levetiracetam, oxcarbazepine, topiramate, valproate.   
 
This analysis also showed no clinically significant effect of the inducers (phenytoin, carbamazepine 
and phenobarbital) on retigabine clearance. 
 
However, steady-state data from a limited number of patients in smaller phase II studies indicated that:  
-  phenytoin can reduce retigabine systemic exposure by 35% 
-  carbamazepine can reduce retigabine systemic exposure by 33% 

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Interaction with digoxin 
 
Data from an in vitro study showed that the N-acetyl metabolite of retigabine (NAMR) inhibited 
P-glycoprotein-mediated transport of digoxin in a concentration-dependent manner.  
 
Based on a study conducted in healthy volunteers, therapeutic doses of retigabine (600-1,200 mg/day) 
resulted in a minor (8-18%) increase in digoxin AUC following a single oral dose of digoxin. The 
increase did not appear to be dependent on retigabine dose and is not considered clinically relevant. 
There was no meaningful change in digoxin Cmax. No dose adjustment of digoxin is needed. 
 
Interaction with anaesthetics 
Trobalt may increase the duration of anaesthesia induced by some anaesthetics (for example thiopental 
sodium; see section 5.1). 
 
Interaction with alcohol 
 
Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual 
blurring in healthy volunteers. It is recommended that patients are advised about the possible effects 
on vision if they take Trobalt with alcohol. 
 
Oral contraceptives 
 
At retigabine doses of up to 750 mg/day, there was no clinically significant effect of retigabine on the 
pharmacokinetics of the estrogen (ethinyl estradiol) or progestogen (norethindrone) components of the 
oral contraceptive pill. In addition, there was no clinically significant effect of the low dose 
combination oral contraceptive pill on the pharmacokinetics of retigabine. 
 
 
4.6 Fertility, pregnancy and lactation 
 
Pregnancy 
 
Risk related to antiepileptic medicinal products in general 
Specialist advice should be given to women who are of childbearing potential. The need for treatment 
with antiepileptic medicinal products should be reviewed when a woman is planning to become 
pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic medicine 
therapy should be avoided as this may lead to breakthrough seizures that could have serious 
consequences for the woman and the unborn child.  
 
The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers 
treated with antiepileptic medicinal products compared with the expected incidence in the general 
population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular 
malformations and neural tube defects. Therapy with multiple antiepileptic medicinal products is 
associated with a higher risk of congenital malformations than monotherapy and therefore 
monotherapy should be used whenever possible. 
 
Risk related to Trobalt 
There are no adequate data from the use of retigabine in pregnant women. Animal studies are 
insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies 
were less than those reached in humans at recommended doses (see section 5.3). In a developmental 
study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in 
auditory startle response development of the offspring (see section 5.3). The clinical significance of 
this finding is not known.  
 
Trobalt is not recommended during pregnancy and in women of childbearing age, not using 
contraception. 

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Breastfeeding 
 
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown 
excretion of retagabine and/or its metabolites in breast milk. A decision on whether to 
continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made 
taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the 
woman. 
 
Fertility 
 
There were no treatment-related effects of retigabine on fertility in animal studies. However, the 
plasma levels achieved in these studies were less than those reached in humans at recommended doses 
(see section 5.3). 
 
The effect of retigabine on human fertility has not been established. 
 
4.7 Effects on ability to drive and use machines 
 
Adverse reactions such as dizziness, somnolence, diplopia and blurred vision were reported in 
controlled clinical studies, particularly during titration (see section 4.8). It is recommended that 
patients are advised about the risk of such adverse reactions at treatment initiation and following each 
titration step, and that they are advised not to drive or operate machinery until they have established 
how Trobalt affects them. 
 
4.8 Undesirable effects 
 
Summary of the safety profile 
 
In pooled safety data from three multicentre, randomised, double-blind, placebo-controlled studies, 
adverse reactions were generally mild to moderate in intensity, and were most commonly reported in 
the first 8 weeks of treatment. There was an apparent dose-relationship for dizziness, somnolence, 
confusional state, aphasia, coordination abnormal, tremor, balance disorder, memory impairment, gait 
disturbance, blurred vision and constipation. 
 
Adverse reactions that were most frequently reported to lead to discontinuation were dizziness, 
somnolence, fatigue and confusional state. 
 
Tabulated list of adverse reactions 
 
The following convention has been used for the classification of adverse reactions: 
 
Very common: ≥1/10 
Common:  ≥1/100 to <1/10 
Uncommon:  ≥1/1,000 to <1/100 
Rare: ≥1/10,000 to <1/1,000 
Very rare: <1/10,000. 
 
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Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. 
 
System Organ 
Class 
 

Very common Common Uncommon 

Metabolism and 
nutrition disorders 
 

 Weight increased 
Increased appetite 

 

Psychiatric 
disorders 
 

 Confusional state 
Psychotic disorders 
Hallucinations 
Disorientation 
Anxiety 
 

 

Nervous system 
disorders 
 

Dizziness 
Somnolence 
 

Amnesia 
Aphasia 
Coordination abnormal 
Vertigo 
Paraesthesia 
Tremor 
Balance disorder 
Memory impairment 
Dysphasia 
Dysarthria 
Disturbance in attention 
Gait disturbance 
Myoclonus 
 

Hypokinesia 

Eye disorders 
 

Pigment changes 
(discolouration) 
of ocular tissues, 
including the 
retina, have been 
observed after 
several years of 
treatment. Some 
of these reports 
have been 
associated with 
visual 
impairment. 
 

Diplopia 
Blurred vision 
Acquired Vitelliform 
Maculopathy 
 

 

Gastrointestinal 
disorders 

 Nausea 
Constipation 
Dyspepsia 
Dry mouth 
 

Dysphagia 

Hepatobiliary 
disorders 

 Increased liver function 
tests 
 

 
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System Organ 
Class 
 

Very common Common Uncommon 

Skin and 
subcutaneous 
disorders 
 

Blue-grey 
discolouration of 
the nails, lips 
and/or skin have 
been observed, 
generally at 
higher doses and 
after several years 
of treatment. 
 

 Skin rash 
Hyperhidrosis 

Renal and urinary 
disorders 
 

 Dysuria 
Urinary hesitation 
Haematuria 
Chromaturia 
 

Urinary retention 
Nephrolithiasis 

General disorders 
and administrative 
site conditions 

Fatigue Asthenia 
Malaise  
Peripheral oedema 
 

 

 
Description of selected adverse reactions 
 
Adverse reactions related to voiding dysfunction, including urinary retention, were reported in 5% of 
retigabine-treated patients in the pooled safety dataset (see section 4.4). The majority of events 
occurred in the first 8 weeks of treatment, and there was no apparent dose-relationship. 
 
In retigabine-treated patients in the pooled dataset, confusional state was reported in 9% of patients, 
hallucinations in 2% of patients and psychotic disorders in 1% of patients (see section 4.4). The 
majority of adverse reactions occurred in the first 8 weeks of treatment, and there was an apparent 
dose-relationship for confusional state only. 
 
Adverse event data from clinical trial subjects showed a rate of event of discolouration of the nails, 
lips, skin and/or mucosa per patient year of exposure of 3.6%. The cumulative incidences of an event 
at 1 year, 2 years, 3 years, 4 years and 5 years of exposure are approximately 1%, 1.8%, 4.4%, 10.2% 
and 16.7% respectively. 
 
Approximately 30-40% of clinical trial subjects who were being treated with retigabine and underwent 
a skin and/or ophthalmological examination had findings of discolouration of nails, lips, skin and/or 
mucosa or non-retinal ocular pigmentation, and approximately 15-30% of clinical trial subjects who 
were being treated with retigabine and underwent an ophthalmological examination had retinal 
pigmentation findings. In addition, cases of acquired vitelliform-type maculopathy have been 
identified, both in clinical studies and as spontaneous reports. 
 
Data from elderly patients indicates that they may be more likely to experience certain central nervous 
system events, including somnolence, amnesia, coordination abnormal, vertigo, tremor, balance 
disorder, memory impairment and gait disturbance. 
 
Reporting of suspected adverse reactions  
 
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It 
allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare 
professionals are asked to report any suspected adverse reactions via the national reporting system 
listed in Appendix V. 
 

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4.9 Overdose 
 
Symptoms and signs 
 
There is limited experience of overdose with retigabine. 
 
Retigabine overdoses in excess of 2,500 mg/day were reported during clinical studies. In addition to 
adverse reactions seen at therapeutic doses, symptoms of retigabine overdose included agitation, 
aggressive behaviour and irritability. There were no reported sequelae. 
 
In a study in volunteers, cardiac arrhythmia (cardiac arrest/asystole or ventricular tachycardia) 
occurred in two subjects within 3 hours of receiving a single 900 mg retigabine dose. The arrhythmias 
spontaneously resolved, and both volunteers recovered without sequelae. 
 
Management 
 
In the event of overdose, it is recommended that the patient is given appropriate supportive therapy as 
clinically indicated, including electrocardiogram (ECG) monitoring. Further management should be as 
recommended by the national poisons centre, where available. 
 
Haemodialysis has been shown to reduce the plasma concentrations of retigabine and NAMR by 
approximately 50%. 
 
 
5. PHARMACOLOGICAL PROPERTIES 
 
5.1  Pharmacodynamic properties 
 
Pharmacotherapeutic group: antiepileptics, other antiepileptics, ATC code: N03AX21. 
 
Mechanism of action 
 
Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are 
important determinants of neuronal activity. In vitro studies indicate that retigabine acts primarily 
through opening neuronal potassium channels (KCNQ2 [Kv7.2] and KCNQ3 [Kv7.3]). This stabilises 
the resting membrane potential and controls the sub-threshold electrical excitability in neurons, thus 
preventing the initiation of epileptiform action potential bursts. Mutations in the KCNQ channels 
underlie several human inheritable disorders, including epilepsy (KCNQ2 and 3). The mechanism of 
action of retigabine on potassium channels has been well documented, however other mechanisms by 
which retigabine may assert an antiepileptic effect have yet to be fully elucidated. 
 
In a range of seizure models, retigabine increased the threshold for seizure induction produced by 
maximal electroshock, pentylenetetrazol, picrotoxin and N-methyl-D-aspartate (NMDA). Retigabine 
also displayed inhibitory properties in multiple kindling models, for example, in the fully kindled state 
and in some cases during the kindling development. In addition, retigabine was effective in preventing 
status epilepticus seizures in rodents with cobalt-induced epileptogenic lesions, and inhibiting tonic 
extensor seizures in genetically susceptible mice. The relevance of these models to human epilepsy, 
however, is not known. 
 
Pharmacodynamic effects 
 
In rats, retigabine increased the sleep time induced by thiopental sodium from approximately 4 min to 
53 min, and the propofol-induced sleep time from approximately 8 min to 12 min. There was no effect 
on sleep time induced by halothane or methohexital sodium. Retigabine may increase the duration of 
anaesthesia induced by some anaesthetics (for example thiopental sodium). 
 

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Clinical efficacy of adjunctive retigabine therapy in partial onset seizures 
 
Three multicentre, randomized, double-blind, placebo-controlled studies in a total of 1239 adult 
patients have been conducted to assess the efficacy of retigabine as adjunctive therapy of partial onset 
seizures, with or without secondary generalisation. All patients enrolled were to have had seizures that 
were not adequately controlled with 1 to 3 concomitant antiepileptic medicinal products, and more 
than 75% of all patients were taking ≥2 concurrent antiepileptic medicinal products. Across all studies, 
patients had a mean duration of epilepsy of 22 years and a median baseline seizure frequency ranging 
from 8 to 12 per 28 days. Patients were randomized to placebo or retigabine at 600, 900 or 
1,200 mg/day (see Table 1). During an 8-week baseline period, patients had to experience ≥4 partial 
onset seizures per 28 days. Patients could not be seizure-free for ≥21 days. The duration of the 
maintenance phase was 8 or 12 weeks. 
 
The primary efficacy endpoints were: 
- percentage change in the 28-day total partial seizure frequency from baseline to the 

double-blind phase (titration and maintenance phases combined) in all three studies 
- responder rate (defined as the percentage of patients with a ≥50% reduction in 28-day total 

partial seizure frequency) from baseline to the maintenance phase (Studies 301 and 302 only). 
 
Retigabine was effective in adjunctive treatment of adults with partial onset seizures in three clinical 
studies (Table 1).  Retigabine was statistically significantly superior to placebo at 600 mg/day 
(one study), 900 mg/day (two studies) and 1,200 mg/day (two studies). 
 
The studies were not designed to evaluate specific combinations of antiepileptic medicinal products. 
Consequently, the efficacy and safety of retigabine when taken concomitantly with antiepileptic 
medicinal products that were less commonly used as background treatment in the clinical studies, 
including levetiracetam, has not been definitely shown. 
 
Table 1. Summary of percentage changes in 28-day total partial seizure frequency and responder 
rates 
 
Study  
(n=population in double-blind phase;  
n=population in maintenance phase) 
 

Placebo Retigabine 
600 

mg/day 
900 

mg/day 
1,200 

mg/day 

Study 205 (n=396; n=303) 
Total partial seizure frequency (median) % change  -13% -23% -29%* -35%* 
Responder rate (secondary endpoint) 
 

26% 28% 41% 41%* 

Study 301 (n=305; n=256) 
Total partial seizure frequency (median) % change -18% ~ ~ -44%* 
Responder rate  
 

23% ~ ~ 56%* 

Study 302 (n=538; n=471) 
Total partial seizure frequency (median) % change -16% -28%* -40%* ~ 
Responder rate  
 

19% 39%* 47%* ~ 

* Statistically significant, p≤0.05 
~ Dose not studied 
 
In open-label extensions of the three placebo-controlled studies, persistence of efficacy was 
maintained over an evaluation period of at least 12 months (365 patients). 
 

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Paediatric population 
 
The European Medicines Agency has waived the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 0 to below 2 years with Lennox Gastaut Syndrome (see section 4.2 
for information on paediatric use). 
 
The European Medicines Agency has deferred the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 2 to below 18 years with Lennox Gastaut Syndrome, and in 
paediatric patients aged 0 to below 18 years with partial onset seizures (see section 4.2 for information 
on paediatric use). 
 
5.2 Pharmacokinetic properties 
 
Absorption 
 
After both single and multiple oral doses, retigabine is rapidly absorbed with median tmax values 
generally between 0.5 and 2 hours. Absolute oral bioavailability of retigabine relative to an 
intravenous dose is approximately 60%. 
 
Administration of retigabine with a high fat meal resulted in no change in the overall extent of 
retigabine absorption, but food reduced the between-subject variability in Cmax (23%) compared to the 
fasted state (41%), and led to an increase in Cmax (38%).  The effect of food on Cmax under usual 
clinical conditions is not expected to be clinically relevant.  Therefore Trobalt may be taken with or 
without food.  
 
Distribution 
 
Retigabine is approximately 80% bound to plasma protein over the concentration range of 0.1 to 
2 µg/ml. The steady state volume of distribution of retigabine is 2 to 3 l/kg following intravenous 
dosing. 
 
Biotransformation 
 
Retigabine is extensively metabolised in humans. A substantial fraction of the retigabine dose is 
converted to inactive N-glucuronides. Retigabine is also metabolised to an N-acetyl metabolite 
(NAMR) that is also subsequently glucuronidated. NAMR has antiepileptic activity, but is less potent 
than retigabine in animal seizure models. 
 
There is no evidence for hepatic oxidative metabolism of retigabine or NAMR by cytochrome P450 
enzymes.  Therefore, co-administration with inhibitors or inducers of cytochrome P450 enzymes is 
unlikely to affect the pharmacokinetics of retigabine or NAMR. 
 
In vitro studies using human liver microsomes showed little or no potential for retigabine to inhibit the 
major cytochrome P450 isoenzymes (including CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, 
CYP2D6, CYP2E1 and CYP3A4/5).  In addition, retigabine and NAMR did not induce CYP1A2 or 
CYP3A4/5 in human primary hepatocytes. Therefore, retigabine is unlikely to affect the 
pharmacokinetics of substrates of the major cytochrome P450 isoenzymes through inhibition or 
induction mechanisms. 
 

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Elimination 
 
Elimination of retigabine occurs via a combination of hepatic metabolism and renal excretion. A total 
of approximately 84% of the dose is recovered in the urine, including the N-acetyl metabolite (18%), 
N-glucuronides of the parent active substance and of the N-acetyl metabolite (24%), or parent active 
substance (36%). Only 14% of retigabine is excreted in the faeces. Retigabine has a plasma half-life of 
approximately 6 to 10 hours. The total clearance of retigabine from plasma following intravenous 
dosing is typically 0.4 to 0.6 l/h/kg. 
 
Linearity 
 
Retigabine pharmacokinetics are essentially linear over the single-dose range of 25 to 600 mg in 
healthy volunteers and up to 1,200 mg daily in patients with epilepsy, with no unexpected 
accumulation following repeated administration. 
 
Special patient populations 
 
Renal impairment 
In a single-dose study, retigabine AUC was increased by approximately 30% in volunteers with mild 
renal impairment (creatinine clearance 50 to 80 ml/min) and by approximately 100% in volunteers 
with moderate to severe renal impairment (creatinine clearance <50 ml/min), relative to healthy 
volunteers.  Adjustment of the Trobalt dose is recommended in patients with moderate to severe renal 
impairment but no adjustment of the Trobalt dose is recommended in patients with mild renal 
impairment (see section 4.2).  
 
In a single-dose study in healthy volunteers and subjects with end stage renal disease, the retigabine 
AUC was increased by approximately 100% in the subjects with end stage renal disease relative to 
healthy volunteers.  
 
In a second single-dose study in subjects with end stage renal disease receiving chronic haemodialysis 
(n= 8), initiation of dialysis at approximately 4 hours after a single dose of retigabine (100 mg) 
resulted in a median reduction in retigabine plasma concentrations of 52% from the start to end of 
dialysis. The percentage decrease in plasma concentration during dialysis ranged from 34% to 60% 
except for one subject who had a 17% reduction. 
 
Hepatic impairment 
In a single-dose study, there were no clinically significant effects on retigabine AUC in volunteers 
with mild hepatic impairment (Child-Pugh score 5 to 6).  The retigabine AUC was increased by 
approximately 50% in volunteers with moderate hepatic impairment (Child-Pugh score 7 to 9) and by 
approximately 100% in volunteers with severe hepatic impairment (Child-Pugh score >9), relative to 
healthy volunteers. Adjustment of the Trobalt dose is recommended in patients with moderate or 
severe hepatic impairment (see section 4.2). 
 
Body weight 
In a population pharmacokinetic analysis, retigabine clearance increased with increasing body surface 
area. However, this increase is not considered to be clinically meaningful, and since retigabine is 
titrated according to individual patient response and tolerability, dose-adjustments are not required on 
the basis of body weight. 
 
Elderly (65 years of age and above) 
In a single-dose study, retigabine was eliminated more slowly by healthy elderly volunteers 
(66 to 82 years of age) relative to healthy young adult volunteers, resulting in a higher AUC 
(approximately 40 to 50%) and longer terminal half-life (30%) (see section 4.2). 
 

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Gender 
The results of a single-dose study showed that in young adult volunteers, retigabine Cmax was 
approximately 65% higher in females than in males, and in elderly volunteers (66 to 82 years of age), 
retigabine Cmax was approximately 75% higher in females compared with males. When Cmax was 
normalized for weight, the values were approximately 30% higher in young females than in males and 
40% higher in elderly females compared with males. However, there was no apparent gender 
difference in weight-normalized clearance, and since retigabine is titrated according to individual 
patient response and tolerability, dose-adjustments are not required on the basis of gender. 
 
Race 
A post-hoc analysis across multiple healthy volunteer studies demonstrated a 20% reduction in 
retigabine clearance in healthy black volunteers relative to healthy Caucasian volunteers. However, 
this effect is not considered clinically significant, therefore no adjustment of the Trobalt dose is 
recommended. 
 
Paediatric population 
The pharmacokinetics of retigabine in children below 12 years of age have not been investigated. 
 
An open-label, multiple dose pharmacokinetic, safety and tolerability study in five subjects aged 
between 12 years to less than 18 years with partial onset seizures determined that the 
pharmacokinetics of retigabine in adolescents were consistent with the pharmacokinetics of retigabine 
in adults.  However, efficacy and safety of retigabine have not been determined in adolescents. 
 
 
5.3 Preclinical safety data 
 
Maximum doses in repeat dose toxicity studies were limited by the exaggerated pharmacologic effects 
of retigabine (including ataxia, hypokinesia and tremor). At no observed effect levels, animal exposure 
in these studies was generally less than that reached in humans at recommended clinical doses. 
 
Distension of the gall bladder was seen in studies with dogs, but there was no evidence of cholestasis 
or other signs of gall bladder dysfunction, and bile ejection volume was unchanged. The gall bladder 
distension in the dog resulted in focal compression of the liver. No signs of gall bladder dysfunction 
were seen clinically. 
 
Non-clinical data reveal no special hazard for humans based on studies of genotoxicity or carcinogenic 
potential. 
 
Reproductive toxicology 
 
Retigabine had no effect on fertility or general reproductive performance. 
 
In rats, retigabine and/or its metabolites crossed the placenta resulting in tissue concentrations that 
were similar in dams and foetuses. 
 
There was no evidence of teratogenicity following administration of retigabine to pregnant animals 
during the period of organogenesis. In a study of peri- and post-natal development in rats, retigabine 
was associated with increased perinatal mortality following administration during pregnancy. In 
addition, there was a delay in auditory startle response development. These findings were apparent at 
exposure levels lower than those obtained with clinically recommended doses and were accompanied 
by maternal toxicities (including ataxia, hypokinesia, tremor and reduced body weight gain). The 
maternal toxicities interfered with higher dosing of the dams and hence deduction of safety margins 
with regard to human therapy.  
 
 

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6. PHARMACEUTICAL PARTICULARS 
 
6.1 List of excipients 
 
Tablet core 
 
Croscarmellose sodium 
Hypromellose 
Magnesium stearate 
Microcrystalline cellulose. 
 
Film-coating 
 
300 mg tablets: 
Polyvinyl alcohol 
Titanium dioxide (E171) 
Talc (E553b) 
Indigo carmine aluminium lake (E132) 
Iron oxide yellow (E172). 
Lecithin (SOY) 
Xanthan gum 
 
6.2 Incompatibilities 
 
Not applicable. 
 
6.3 Shelf life 
 
3 years. 
 
6.4 Special precautions for storage 
 
This medicinal product does not require any special storage conditions. 
 
6.5 Nature and contents of container 
 
300 mg tablets:  
Opaque PVC-PVDC-aluminium foil blisters. Pack containing 84 film-coated tablets; multi-pack 
comprising 168 (2 x 84) film-coated tablets. 
 
 
Not all pack sizes may be marketed. 
 
6.6 Special precautions for disposal  
 
No special requirements. 
 
 
7. MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 

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8. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/009, EU/1/11/681/010 
 
 
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION 
 
Date of first authorisation: 28 March 2011  
Date of latest renewal: 14 January 2016 
 
10. DATE OF REVISION OF THE TEXT 
 
 
 
 
Detailed information on this medicinal product is available on the website of the European Medicines 
Agency http://www.ema.europa.eu. 

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1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 400 mg film-coated tablets 
 
 
2. QUALITATIVE AND QUANTITATIVE COMPOSITION 
 
Each film-coated tablet contains 400 mg of retigabine. 
 
For the full list of excipients, see section 6.1. 
 
 
3. PHARMACEUTICAL FORM 
 
Film-coated tablet. 
 
Purple, oblong, film-coated tablets of 8.1 mm x 18 mm, marked with “RTG-400” on one side.  
 
 
4. CLINICAL PARTICULARS 
 
4.1 Therapeutic indications 
 
Trobalt is indicated as adjunctive treatment of drug-resistant partial onset seizures with or without 
secondary generalization in patients aged 18 years or older with epilepsy, where other appropriate 
combinations with other medicinal products have proved inadequate or have not been tolerated. 
 
4.2 Posology and method of administration 
 
Posology 
 
Trobalt must be titrated, according to individual patient response, in order to optimise the balance 
between efficacy and tolerability. 
 
The maximum total daily starting dose is 300 mg (100 mg three times daily). Thereafter, the total daily 
dose is increased by a maximum of 150 mg every week, according to the individual patient response 
and tolerability. An effective maintenance dose is expected to be between 600 mg/day and 
1,200 mg/day. 
 
The maximum total maintenance dose is 1,200 mg/day. The safety and efficacy of doses higher than 
1,200 mg/day have not been established. 
 
If patients miss one dose or more, it is recommended that they take a single dose as soon as they 
remember. 
 
After taking a missed dose, at least 3 hours should be allowed before the next dose and then the 
normal dosing schedule should be resumed. 
 
When withdrawing Trobalt, the dose must be gradually reduced over a period of at least 3 weeks (see 
section 4.4).  
 
Elderly (65 years of age and above) 
 
There are only limited data on the safety and efficacy of retigabine in patients aged 65 years and 
above. A reduction in the initial and maintenance dose of Trobalt is recommended in elderly patients. 

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The total daily starting dose is 150 mg/day and during the titration period the total daily dose should 
be increased by a maximum of 150 mg every week, according to the individual patient response and 
tolerability. Doses greater than 900 mg/day are not recommended (see sections 4.4 and 5.2). 
 
Renal impairment 
 
Retigabine and its metabolites are eliminated principally by renal excretion. 
 
No dose adjustment is required in patients with mild renal impairment (creatinine clearance 50 to 
80 ml/min; see section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe renal impairment (creatinine clearance <50 ml/min; see section 5.2). The total 
daily starting dose is 150 mg, and it is recommended that during the titration period, the total daily 
dose is increased by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
For patients with end-stage renal disease receiving haemodialysis, the three daily doses should be 
taken as usual on the dialysis day. In addition, a single supplemental dose is recommended 
immediately after haemodialysis. If breakthrough seizures occur towards the end of dialysis then an 
additional supplemental dose may be considered at the start of subsequent dialysis sessions. 
 
Hepatic impairment 
 
No dose reduction is required in patients with mild hepatic impairment (Child-Pugh score 5 to 6; see 
section 5.2). 
 
A 50% reduction in the initial and maintenance dose of Trobalt is recommended in patients with 
moderate or severe hepatic impairment (Child-Pugh score ≥7; see section 5.2). The total daily starting 
dose is 150 mg, and it is recommended that during the titration period, the total daily dose is increased 
by 50 mg every week, to a maximum total dose of 600 mg/day. 
 
Paediatric population 
 
The safety and efficacy of retigabine in children below 18 years of age has not yet been established 
(see section 5.2). Currently available pharmacokinetic data are described in section 5.2, but no 
recommendation on a posology can be made. 
 
 
Method of administration 
 
Trobalt is for oral use. The tablets must be taken in three divided doses each day.  The tablets should 
be swallowed whole, and not chewed, crushed or divided. 
 
Trobalt may be taken with or without food (see section 5.2). 
 
4.3 Contraindications 
 
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1. 
 
4.4 Special warnings and precautions for use 
 
Eye disorders 
 
Pigment changes (discolouration) of ocular tissues, including the retina have been reported in long-
term clinical studies with retigabine,  sometimes but not always in conjunction with pigment changes 
of the skin, lips or nails (see below paragraph and section 4.8). Reversibility of retinal pigmentation 

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after retigabine discontinuation has been reported in some subjects. The long-term prognosis of these 
findings is currently unknown, but some of the reports have been associated with visual impairment. 
 
In addition a distinct form of macular abnormality with features of vitelliform maculopathy (see 
section 4.8) has also been identified, in most cases diagnosed with optical coherence tomography 
(OCT) imaging. The rate of progression of vitelliform maculopathy and its impact on retinal and 
macular function and vision is unclear. Vision abnormalities (field constriction, loss of central 
sensitivity, and reduced visual acuity) have been reported.  
 
All patients should undergo comprehensive ophthalmological examinations at baseline and at least 
every six months, which should include visual acuity, slit-lamp examination, dilated fundus 
photography, and macular OCT imaging. If retinal pigment changes, vitelliform maculopathy or vision 
changes are detected, treatment with Trobalt should only be continued after a careful re-assessment of 
the balance of benefits and risks. If continued, the patient should be monitored more closely. 
 
Skin disorders 
 
Pigment changes (discolouration) of the skin, lips or nails have been reported in long-term clinical 
studies with retigabine, sometimes but not always in conjunction with pigment changes of ocular 
tissues (see above paragraph and section 4.8). In patients who develop these changes, treatment with 
Trobalt should only be continued after a careful re-assessment  of the balance of benefits and risks. 
 
Urinary retention 
 
Urinary retention, dysuria and urinary hesitation were reported in controlled clinical studies with 
retigabine, generally within the first 8 weeks of treatment (see section 4.8). Trobalt must be used with 
caution in patients at risk of urinary retention, and it is recommended that patients are advised about 
the risk of these possible effects. 
 
QT interval 
 
A study of cardiac conduction in healthy subjects has demonstrated that retigabine titrated to 1,200 
mg/day produced a QT-prolonging effect. A mean increase in Individual Corrected QT Interval (QTcI) 
of up to 6.7 ms (upper bound of 95% one-sided CI 12.6 ms) was observed within 3 hours of dosing. 
Caution should be taken when Trobalt is prescribed with medicinal products known to increase 
QT interval and in patients with known prolonged QT interval, congestive cardiac failure, ventricular 
hypertrophy, hypokalaemia or hypomagnesaemia and in patients initiating treatment who are 65 years 
of age and above. 
 
In these patients it is recommended that an electrocardiogram (ECG) is recorded before initiation of 
treatment with Trobalt and in those with a corrected QT interval >440ms at baseline, an ECG should 
be recorded on reaching the maintenance dose. 
 
Psychiatric disorders 
 
Confusional state, psychotic disorders and hallucinations were reported in controlled clinical studies 
with retigabine (see section 4.8).  These effects generally occurred within the first 8 weeks of 
treatment, and frequently led to treatment withdrawal in affected patients. It is recommended that 
patients are advised about the risk of these possible effects. 
 

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Suicide risk 
 
Suicidal ideation and behaviour have been reported in patients treated with antiepileptic agents in 
several indications. A meta-analysis of randomised placebo-controlled trials of antiepileptic medicinal 
products has also shown a small increased risk of suicidal ideation and behaviour. The mechanism of 
this risk is not known and the available data do not exclude the possibility of an increased risk for 
retigabine. 
 
Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate 
treatment should be considered. Patients (and caregivers of patients) should be advised to seek medical 
advice if signs of suicidal ideation or behaviour emerge. 
 
Elderly (65 years of age and above) 
 
Elderly patients may be at increased risk of central nervous system events, urinary retention and atrial 
fibrillation.  Trobalt must be used with caution in this population and a reduced initial and 
maintenance dose is recommended (see sections 4.2 and 5.2). 
 
Withdrawal seizures 
 
Trobalt must be withdrawn gradually to minimise the potential for rebound seizures.  It is 
recommended that the Trobalt dose is reduced over a period of at least 3 weeks, unless safety concerns 
require an abrupt withdrawal (see section 4.2). 
 
Laboratory tests 
 
Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine 
bilirubin, which can result in falsely elevated readings. 
 
 
4.5 Interaction with other medicinal products and other forms of interaction 
 
Interaction studies have only been performed in adults. 
 
Other antiepileptic medicinal products 
 
In vitro data indicated a low potential for interaction with other antiepileptic medicinal products (see 
section 5.2).  The drug interaction potential was, therefore, evaluated based on a pooled analysis 
across clinical studies and whilst not considered as robust as stand-alone clinical interaction studies, 
the results support the in vitro data. 
 
Based on these pooled data, retigabine did not cause clinically significant effects on the plasma trough 
concentrations of the following antiepileptic medicinal products: 
- carbamazepine, clobazam, clonazepam, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, 

phenobarbital, phenytoin, pregabalin, topiramate, valproate, zonisamide. 
 
Further, based on pooled data, there were no clinically significant effects of the following antiepileptic 
medicinal products on retigabine pharmacokinetics: 
- lamotrigine, levetiracetam, oxcarbazepine, topiramate, valproate.   
 
This analysis also showed no clinically significant effect of the inducers (phenytoin, carbamazepine 
and phenobarbital) on retigabine clearance. 
 
However, steady-state data from a limited number of patients in smaller phase II studies indicated that:  
-  phenytoin can reduce retigabine systemic exposure by 35% 
-  carbamazepine can reduce retigabine systemic exposure by 33% 

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Interaction with digoxin 
 
Data from an in vitro study showed that the N-acetyl metabolite of retigabine (NAMR) inhibited 
P-glycoprotein-mediated transport of digoxin in a concentration-dependent manner.  
 
Based on a study conducted in healthy volunteers, therapeutic doses of retigabine (600-1,200 mg/day) 
resulted in a minor (8-18%) increase in digoxin AUC following a single oral dose of digoxin. The 
increase did not appear to be dependent on retigabine dose and is not considered clinically relevant. 
There was no meaningful change in digoxin Cmax. No dose adjustment of digoxin is needed. 
 
Interaction with anaesthetics 
 
Trobalt may increase the duration of anaesthesia induced by some anaesthetics (for example thiopental 
sodium; see section 5.1). 
 
Interaction with alcohol 
 
Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual 
blurring in healthy volunteers. It is recommended that patients are advised about the possible effects 
on vision if they take Trobalt with alcohol. 
Oral contraceptives 
 
At retigabine doses of up to 750 mg/day, there was no clinically significant effect of retigabine on the 
pharmacokinetics of the estrogen (ethinyl estradiol) or progestogen (norethindrone) components of the 
oral contraceptive pill. In addition, there was no clinically significant effect of the low dose 
combination oral contraceptive pill on the pharmacokinetics of retigabine. 
 
 
4.6 Fertility, pregnancy and lactation 
 
Pregnancy 
 
Risk related to antiepileptic medicinal products in general 
Specialist advice should be given to women who are of childbearing potential. The need for treatment 
with antiepileptic medicinal products should be reviewed when a woman is planning to become 
pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic medicine 
therapy should be avoided as this may lead to breakthrough seizures that could have serious 
consequences for the woman and the unborn child.  
 
The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers 
treated with antiepileptic medicinal products compared with the expected incidence in the general 
population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular 
malformations and neural tube defects. Therapy with multiple antiepileptic medicinal products is 
associated with a higher risk of congenital malformations than monotherapy and therefore 
monotherapy should be used whenever possible. 
 
Risk related to Trobalt 
There are no adequate data from the use of retigabine in pregnant women. Animal studies are 
insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies 
were less than those reached in humans at recommended doses (see section 5.3). In a developmental 
study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in 
auditory startle response development of the offspring (see section 5.3). The clinical significance of 
this finding is not known.  
 
Trobalt is not recommended during pregnancy and in women of childbearing age, not using 
contraception. 

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Breastfeeding 
 
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown 
excretion of retagabine and/or its metabolites in breast milk. A decision on whether to 
continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made 
taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the 
woman. 
 
Fertility 
 
There were no treatment-related effects of retigabine on fertility in animal studies. However, the 
plasma levels achieved in these studies were less than those reached in humans at recommended doses 
(see section 5.3). 
 
The effect of retigabine on human fertility has not been established. 
 
4.7 Effects on ability to drive and use machines 
 
Adverse reactions such as dizziness, somnolence, diplopia and blurred vision were reported in 
controlled clinical studies, particularly during titration (see section 4.8). It is recommended that 
patients are advised about the risk of such adverse reactions at treatment initiation and following each 
titration step, and that they are advised not to drive or operate machinery until they have established 
how Trobalt affects them. 
 
4.8 Undesirable effects 
 
Summary of the safety profile 
 
In pooled safety data from three multicentre, randomised, double-blind, placebo-controlled studies, 
adverse reactions were generally mild to moderate in intensity, and were most commonly reported in 
the first 8 weeks of treatment. There was an apparent dose-relationship for dizziness, somnolence, 
confusional state, aphasia, coordination abnormal, tremor, balance disorder, memory impairment, gait 
disturbance, blurred vision and constipation. 
 
Adverse reactions that were most frequently reported to lead to discontinuation were dizziness, 
somnolence, fatigue and confusional state. 
 
Tabulated list of adverse reactions 
 
The following convention has been used for the classification of adverse reactions: 
 
Very common: ≥1/10 
Common:  ≥1/100 to <1/10 
Uncommon:  ≥1/1,000 to <1/100 
Rare: ≥1/10,000 to <1/1,000 
Very rare: <1/10,000. 
 
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Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. 
 
System Organ 
Class 
 

Very common Common Uncommon 

Metabolism and 
nutrition disorders 
 

 Weight increased 
Increased appetite 

 

Psychiatric 
disorders 
 

 Confusional state 
Psychotic disorders 
Hallucinations 
Disorientation 
Anxiety 
 

 

Nervous system 
disorders 
 

Dizziness 
Somnolence 
 

Amnesia 
Aphasia 
Coordination abnormal 
Vertigo 
Paraesthesia 
Tremor 
Balance disorder 
Memory impairment 
Dysphasia 
Dysarthria 
Disturbance in attention 
Gait disturbance 
Myoclonus 
 

Hypokinesia 

Eye disorders 
 

Pigment changes 
(discolouration) 
of ocular tissues, 
including the 
retina, have been 
observed after 
several years of 
treatment. Some 
of these reports 
have been 
associated with 
visual 
impairment. 
 

Diplopia 
Blurred vision 
Acquired Vitelliform 
Maculopathy 
 

 

Gastrointestinal 
disorders 

 Nausea 
Constipation 
Dyspepsia 
Dry mouth 
 

Dysphagia 

Hepatobiliary 
disorders 

 Increased liver function 
tests 
 

 
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System Organ 
Class 
 

Very common Common Uncommon 

Skin and 
subcutaneous 
disorders 
 

Blue-grey 
discolouration of 
the nails, lips 
and/or skin have 
been observed, 
generally at 
higher doses and 
after several years 
of treatment. 
 

 Skin rash 
Hyperhidrosis 

Renal and urinary 
disorders 
 

 Dysuria 
Urinary hesitation 
Haematuria 
Chromaturia 
 

Urinary retention 
Nephrolithiasis 

General disorders 
and administrative 
site conditions 

Fatigue Asthenia 
Malaise  
Peripheral oedema 
 

 

 
Description of selected adverse reactions 
Adverse reactions related to voiding dysfunction, including urinary retention, were reported in 5% of 
retigabine-treated patients in the pooled safety dataset (see section 4.4). The majority of events 
occurred in the first 8 weeks of treatment, and there was no apparent dose-relationship. 
 
In retigabine-treated patients in the pooled dataset, confusional state was reported in 9% of patients, 
hallucinations in 2% of patients and psychotic disorders in 1% of patients (see section 4.4). The 
majority of adverse reactions occurred in the first 8 weeks of treatment, and there was an apparent 
dose-relationship for confusional state only. 
 
Adverse event data from clinical trial subjects showed a rate of event of discolouration of the nails, 
lips, skin and/or mucosa per patient year of exposure of 3.6%. The cumulative incidences of an event 
at 1 year, 2 years, 3 years, 4 years and 5 years of exposure are approximately 1%, 1.8%, 4.4%, 10.2% 
and 16.7% respectively. 
 
Approximately 30-40% of clinical trial subjects who were being treated with retigabine and underwent 
a skin and/or ophthalmological examination had findings of discolouration of nails, lips, skin and/or 
mucosa or non-retinal ocular pigmentation, and approximately 15-30% of clinical trial subjects who 
were being treated with retigabine and underwent an ophthalmological examination had retinal 
pigmentation findings. In addition, cases of acquired vitelliform-type maculopathy have been 
identified, both in clinical studies and as spontaneous reports. 
 
Data from elderly patients indicates that they may be more likely to experience certain central nervous 
system events, including somnolence, amnesia, coordination abnormal, vertigo, tremor, balance 
disorder, memory impairment and gait disturbance. 
 
 
Reporting of suspected adverse reactions  
 
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It 
allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare 
professionals are asked to report any suspected adverse reactions via the national reporting system 
listed in Appendix V. 
 

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4.9 Overdose 
 
Symptoms and signs 
 
There is limited experience of overdose with retigabine. 
 
Retigabine overdoses in excess of 2,500 mg/day were reported during clinical studies. In addition to 
adverse reactions seen at therapeutic doses, symptoms of retigabine overdose included agitation, 
aggressive behaviour and irritability. There were no reported sequelae. 
 
In a study in volunteers, cardiac arrhythmia (cardiac arrest/asystole or ventricular tachycardia) 
occurred in two subjects within 3 hours of receiving a single 900 mg retigabine dose. The arrhythmias 
spontaneously resolved, and both volunteers recovered without sequelae. 
 
Management 
 
In the event of overdose, it is recommended that the patient is given appropriate supportive therapy as 
clinically indicated, including electrocardiogram (ECG) monitoring. Further management should be as 
recommended by the national poisons centre, where available. 
 
Haemodialysis has been shown to reduce the plasma concentrations of retigabine and NAMR by 
approximately 50%. 
 
 
5. PHARMACOLOGICAL PROPERTIES 
 
5.1  Pharmacodynamic properties 
 
Pharmacotherapeutic group: antiepileptics, other antiepileptics, ATC code: N03AX21. 
 
Mechanism of action 
 
Potassium channels are one of the voltage-gated ion channels found in neuronal cells and are 
important determinants of neuronal activity. In vitro studies indicate that retigabine acts primarily 
through opening neuronal potassium channels (KCNQ2 [Kv7.2] and KCNQ3 [Kv7.3]). This stabilises 
the resting membrane potential and controls the sub-threshold electrical excitability in neurons, thus 
preventing the initiation of epileptiform action potential bursts. Mutations in the KCNQ channels 
underlie several human inheritable disorders, including epilepsy (KCNQ2 and 3). The mechanism of 
action of retigabine on potassium channels has been well documented, however other mechanisms by 
which retigabine may assert an antiepileptic effect have yet to be fully elucidated. 
 
In a range of seizure models, retigabine increased the threshold for seizure induction produced by 
maximal electroshock, pentylenetetrazol, picrotoxin and N-methyl-D-aspartate (NMDA). Retigabine 
also displayed inhibitory properties in multiple kindling models, for example, in the fully kindled state 
and in some cases during the kindling development. In addition, retigabine was effective in preventing 
status epilepticus seizures in rodents with cobalt-induced epileptogenic lesions, and inhibiting tonic 
extensor seizures in genetically susceptible mice. The relevance of these models to human epilepsy, 
however, is not known. 
 
Pharmacodynamic effects 
 
In rats, retigabine increased the sleep time induced by thiopental sodium from approximately 4 min to 
53 min, and the propofol-induced sleep time from approximately 8 min to 12 min. There was no effect 
on sleep time induced by halothane or methohexital sodium. Retigabine may increase the duration of 
anaesthesia induced by some anaesthetics (for example thiopental sodium). 
 

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Clinical efficacy of adjunctive retigabine therapy in partial onset seizures 
 
Three multicentre, randomized, double-blind, placebo-controlled studies in a total of 1239 adult 
patients have been conducted to assess the efficacy of retigabine as adjunctive therapy of partial onset 
seizures, with or without secondary generalisation. All patients enrolled were to have had seizures that 
were not adequately controlled with 1 to 3 concomitant antiepileptic medicinal products, and more 
than 75% of all patients were taking ≥2 concurrent antiepileptic medicinal products. Across all studies, 
patients had a mean duration of epilepsy of 22 years and a median baseline seizure frequency ranging 
from 8 to 12 per 28 days. Patients were randomized to placebo or retigabine at 600, 900 or 
1,200 mg/day (see Table 1). During an 8-week baseline period, patients had to experience ≥4 partial 
onset seizures per 28 days. Patients could not be seizure-free for ≥21 days. The duration of the 
maintenance phase was 8 or 12 weeks. 
 
The primary efficacy endpoints were: 
- percentage change in the 28-day total partial seizure frequency from baseline to the 

double-blind phase (titration and maintenance phases combined) in all three studies 
- responder rate (defined as the percentage of patients with a ≥50% reduction in 28-day total 

partial seizure frequency) from baseline to the maintenance phase (Studies 301 and 302 only). 
 
Retigabine was effective in adjunctive treatment of adults with partial onset seizures in three clinical 
studies (Table 1).  Retigabine was statistically significantly superior to placebo at 600 mg/day 
(one study), 900 mg/day (two studies) and 1,200 mg/day (two studies). 
 
The studies were not designed to evaluate specific combinations of antiepileptic medicinal products. 
Consequently, the efficacy and safety of retigabine when taken concomitantly with antiepileptic 
medicinal products that were less commonly used as background treatment in the clinical studies, 
including levetiracetam, has not been definitely shown. 
 
Table 1. Summary of percentage changes in 28-day total partial seizure frequency and responder 
rates 
 
Study  
(n=population in double-blind phase;  
n=population in maintenance phase) 
 

Placebo Retigabine 
600 

mg/day 
900 

mg/day 
1,200 

mg/day 

Study 205 (n=396; n=303) 
Total partial seizure frequency (median) % change  -13% -23% -29%* -35%* 
Responder rate (secondary endpoint) 
 

26% 28% 41% 41%* 

Study 301 (n=305; n=256) 
Total partial seizure frequency (median) % change -18% ~ ~ -44%* 
Responder rate  
 

23% ~ ~ 56%* 

Study 302 (n=538; n=471) 
Total partial seizure frequency (median) % change -16% -28%* -40%* ~ 
Responder rate  
 

19% 39%* 47%* ~ 

* Statistically significant, p≤0.05 
~ Dose not studied 
 
In open-label extensions of the three placebo-controlled studies, persistence of efficacy was 
maintained over an evaluation period of at least 12 months (365 patients). 
 

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Paediatric population 
 
The European Medicines Agency has waived the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 0 to below 2 years with Lennox Gastaut Syndrome (see section 4.2 
for information on paediatric use). 
 
The European Medicines Agency has deferred the obligation to submit the results of studies with 
Trobalt in paediatric patients aged 2 to below 18 years with Lennox Gastaut Syndrome, and in 
paediatric patients aged 0 to below 18 years with partial onset seizures (see section 4.2 for information 
on paediatric use). 
 
5.2 Pharmacokinetic properties 
 
Absorption 
 
After both single and multiple oral doses, retigabine is rapidly absorbed with median tmax values 
generally between 0.5 and 2 hours. Absolute oral bioavailability of retigabine relative to an 
intravenous dose is approximately 60%. 
 
Administration of retigabine with a high fat meal resulted in no change in the overall extent of 
retigabine absorption, but food reduced the between-subject variability in Cmax (23%) compared to the 
fasted state (41%), and led to an increase in Cmax (38%).  The effect of food on Cmax under usual 
clinical conditions is not expected to be clinically relevant.  Therefore Trobalt may be taken with or 
without food.  
 
Distribution 
 
Retigabine is approximately 80% bound to plasma protein over the concentration range of 0.1 to 
2 µg/ml. The steady state volume of distribution of retigabine is 2 to 3 l/kg following intravenous 
dosing. 
 
Biotransformation 
 
Retigabine is extensively metabolised in humans. A substantial fraction of the retigabine dose is 
converted to inactive N-glucuronides. Retigabine is also metabolised to an N-acetyl metabolite 
(NAMR) that is also subsequently glucuronidated. NAMR has antiepileptic activity, but is less potent 
than retigabine in animal seizure models. 
 
There is no evidence for hepatic oxidative metabolism of retigabine or NAMR by cytochrome P450 
enzymes.  Therefore, co-administration with inhibitors or inducers of cytochrome P450 enzymes is 
unlikely to affect the pharmacokinetics of retigabine or NAMR. 
 
In vitro studies using human liver microsomes showed little or no potential for retigabine to inhibit the 
major cytochrome P450 isoenzymes (including CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, 
CYP2D6, CYP2E1 and CYP3A4/5).  In addition, retigabine and NAMR did not induce CYP1A2 or 
CYP3A4/5 in human primary hepatocytes. Therefore, retigabine is unlikely to affect the 
pharmacokinetics of substrates of the major cytochrome P450 isoenzymes through inhibition or 
induction mechanisms. 
 

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Elimination 
 
Elimination of retigabine occurs via a combination of hepatic metabolism and renal excretion. A total 
of approximately 84% of the dose is recovered in the urine, including the N-acetyl metabolite (18%), 
N-glucuronides of the parent active substance and of the N-acetyl metabolite (24%), or parent active 
substance (36%). Only 14% of retigabine is excreted in the faeces. Retigabine has a plasma half-life of 
approximately 6 to 10 hours. The total clearance of retigabine from plasma following intravenous 
dosing is typically 0.4 to 0.6 l/h/kg. 
 
Linearity 
 
Retigabine pharmacokinetics are essentially linear over the single-dose range of 25 to 600 mg in 
healthy volunteers and up to 1,200 mg daily in patients with epilepsy, with no unexpected 
accumulation following repeated administration. 
 
Special patient populations 
 
Renal impairment 
In a single-dose study, retigabine AUC was increased by approximately 30% in volunteers with mild 
renal impairment (creatinine clearance 50 to 80 ml/min) and by approximately 100% in volunteers 
with moderate to severe renal impairment (creatinine clearance <50 ml/min), relative to healthy 
volunteers.  Adjustment of the Trobalt dose is recommended in patients with moderate to severe renal 
impairment but no adjustment of the Trobalt dose is recommended in patients with mild renal 
impairment (see section 4.2).  
 
In a single-dose study in healthy volunteers and subjects with end stage renal disease, the retigabine 
AUC was increased by approximately 100% in the subjects with end stage renal disease relative to 
healthy volunteers.  
 
In a second single-dose study in subjects with end stage renal disease receiving chronic haemodialysis 
(n= 8), initiation of dialysis at approximately 4 hours after a single dose of retigabine (100 mg) 
resulted in a median reduction in retigabine plasma concentrations of 52% from the start to end of 
dialysis. The percentage decrease in plasma concentration during dialysis ranged from 34% to 60% 
except for one subject who had a 17% reduction. 
 
Hepatic impairment 
In a single-dose study, there were no clinically significant effects on retigabine AUC in volunteers 
with mild hepatic impairment (Child-Pugh score 5 to 6).  The retigabine AUC was increased by 
approximately 50% in volunteers with moderate hepatic impairment (Child-Pugh score 7 to 9) and by 
approximately 100% in volunteers with severe hepatic impairment (Child-Pugh score >9), relative to 
healthy volunteers. Adjustment of the Trobalt dose is recommended in patients with moderate or 
severe hepatic impairment (see section 4.2). 
 
Body weight 
In a population pharmacokinetic analysis, retigabine clearance increased with increasing body surface 
area. However, this increase is not considered to be clinically meaningful, and since retigabine is 
titrated according to individual patient response and tolerability, dose-adjustments are not required on 
the basis of body weight. 
 
Elderly (65 years of age and above) 
In a single-dose study, retigabine was eliminated more slowly by healthy elderly volunteers 
(66 to 82 years of age) relative to healthy young adult volunteers, resulting in a higher AUC 
(approximately 40 to 50%) and longer terminal half-life (30%) (see section 4.2). 
 

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Gender 
The results of a single-dose study showed that in young adult volunteers, retigabine Cmax was 
approximately 65% higher in females than in males, and in elderly volunteers (66 to 82 years of age), 
retigabine Cmax was approximately 75% higher in females compared with males. When Cmax was 
normalized for weight, the values were approximately 30% higher in young females than in males and 
40% higher in elderly females compared with males. However, there was no apparent gender 
difference in weight-normalized clearance, and since retigabine is titrated according to individual 
patient response and tolerability, dose-adjustments are not required on the basis of gender. 
 
Race 
A post-hoc analysis across multiple healthy volunteer studies demonstrated a 20% reduction in 
retigabine clearance in healthy black volunteers relative to healthy Caucasian volunteers. However, 
this effect is not considered clinically significant, therefore no adjustment of the Trobalt dose is 
recommended. 
 
Paediatric population 
The pharmacokinetics of retigabine in children below 12 years of age have not been investigated. 
 
An open-label, multiple dose pharmacokinetic, safety and tolerability study in five subjects aged 
between 12 years to less than 18 years with partial onset seizures determined that the 
pharmacokinetics of retigabine in adolescents were consistent with the pharmacokinetics of retigabine 
in adults.  However, efficacy and safety of retigabine have not been determined in adolescents. 
 
 
5.3 Preclinical safety data 
 
Maximum doses in repeat dose toxicity studies were limited by the exaggerated pharmacologic effects 
of retigabine (including ataxia, hypokinesia and tremor). At no observed effect levels, animal exposure 
in these studies was generally less than that reached in humans at recommended clinical doses. 
 
Distension of the gall bladder was seen in studies with dogs, but there was no evidence of cholestasis 
or other signs of gall bladder dysfunction, and bile ejection volume was unchanged. The gall bladder 
distension in the dog resulted in focal compression of the liver. No signs of gall bladder dysfunction 
were seen clinically. 
 
Non-clinical data reveal no special hazard for humans based on studies of genotoxicity or carcinogenic 
potential. 
 
Reproductive toxicology 
 
Retigabine had no effect on fertility or general reproductive performance. 
 
In rats, retigabine and/or its metabolites crossed the placenta resulting in tissue concentrations that 
were similar in dams and foetuses. 
 
There was no evidence of teratogenicity following administration of retigabine to pregnant animals 
during the period of organogenesis. In a study of peri- and post-natal development in rats, retigabine 
was associated with increased perinatal mortality following administration during pregnancy. In 
addition, there was a delay in auditory startle response development. These findings were apparent at 
exposure levels lower than those obtained with clinically recommended doses and were accompanied 
by maternal toxicities (including ataxia, hypokinesia, tremor and reduced body weight gain). The 
maternal toxicities interfered with higher dosing of the dams and hence deduction of safety margins 
with regard to human therapy.  
 
 

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6. PHARMACEUTICAL PARTICULARS 
 
6.1 List of excipients 
 
Tablet core 
 
Croscarmellose sodium 
Hypromellose 
Magnesium stearate 
Microcrystalline cellulose. 
 
Film-coating 
 
400 mg tablets: 
Polyvinyl alcohol  
Titanium dioxide (E171) 
Talc (E553b) 
Indigo carmine aluminium lake (E132) 
Carmine (E120). 
Lecithin (SOY) 
Xanthan gum 
 
 
6.2 Incompatibilities 
 
Not applicable. 
 
6.3 Shelf life 
 
3 years. 
 
6.4 Special precautions for storage 
 
This medicinal product does not require any special storage conditions. 
 
6.5 Nature and contents of container 
 
400 mg tablets: 
Opaque PVC-PVDC-aluminium foil blisters. Pack containing 84 film-coated tablets; multi-pack 
comprising 168 (2 x 84) film-coated tablets. 
 
Not all pack sizes may be marketed. 
 
6.6 Special precautions for disposal  
 
No special requirements. 
 
 
7. MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 

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8. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/011, EU/1/11/681/012 
 
 
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION 
 
Date of first authorisation: 28 March 2011  
Date of latest renewal: 14 January 2016 
 
 
10. DATE OF REVISION OF THE TEXT 
 
 
 
 
Detailed information on this medicinal product is available on the website of the European Medicines 
Agency http://www.ema.europa.eu. 

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77 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

ANNEX II 
 

A. MANUFACTURER(S) RESPONSIBLE FOR BATCH RELEASE 
 
B. CONDITIONS OR RESTRICTIONS REGARDING SUPPLY AND USE 
C. OTHER CONDITIONS AND REQUIREMENTS OF THE MARKETING 
 AUTHORISATION 
 
D. CONDITIONS OR RESTRICTIONS WITH REGARD TO THE SAFE AND 
 EFFECTIVE USE OF THE MEDICINAL PRODUCT 
 
 

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A. MANUFACTURER(S) RESPONSIBLE FOR BATCH RELEASE 
 
 
Name and address of the manufacturer(s) responsible for batch release 
 

Glaxo Wellcome S.A. 
Avda Extremadura 3 
Aranda de Duero 
E-09400 Burgos 
Spain 
 
B. CONDITIONS OR RESTRICTIONS REGARDING SUPPLY AND USE 
 
 
Medicinal product subject to medical prescription. 
 

 
C OTHER CONDITIONS AND REQUIREMENTS OF THE MARKETING 
 AUTHORISATION 
 
• Periodic Safety Update Reports 
 
The  requirements for submission of periodic safety updates reports for this medicinal product 
are set out in the list of Union reference dates (EURD list) provided for under Article 107c(7) of 
Directive 2001/83/EC and any subsequent updates published on the European medicines web-
portal. 
 
 
D.  CONDITIONS OR RESTRICTIONS WITH REGARD TO THE SAFE AND 
EFFECTIVE USE OF THE MEDICINAL PRODUCT 
 
• Risk Management Plan (RMP) 

The MAH shall perform the required pharmacovigilance activities and interventions detailed in 
the agreed RMP presented in Module 1.8.2 of the Marketing Authorisation and any agreed 
subsequent updates of the RMP. 
 
An updated RMP should be submitted: 

• At the request of the European Medicines Agency; 
• Whenever the risk management system is modified, especially as the result of new information 

being received that may lead to a significant change to the benefit/risk profile or as the result of 
an important (pharmacovigilance or risk minimisation) milestone being reached. 

 
 
• Additional risk minimisation measures 
 
Prior to launch in each Member State, and also after changes to the key elements in the educational 
material the MAH shall agree the final educational material with the National Competent Authority. 
 
The MAH shall ensure that, at launch and after launch, neurologists, ophthalmologists and other 
healthcare professionals (according to national requirements) are provided with a physician 
information pack containing the following elements: 
 
• The Summary of Product Characteristics 

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79 

• A physician’s guide to prescribing. When applicable, a cover letter highlighting the main changes 
should also be included as part of the educational materials. The physician's guide should include 
the following key messages: 
− The need to inform patients that TROBALT may cause or potentiate symptoms of urinary 

retention/urinary hesitation 
− The need to inform patients on adverse events related to QT interval prolongation 
− Caution when using TROBALT in patients with a cardiac disease or those taking medicines 

concomitantly known to cause QT prolongation 
− The need to inform patients that TROBALT may cause a confusional state, hallucinations and 

psychotic disorders and the need to comply with dose titration to minimize these risks;  
− The need to inform patients that TROBALT may cause pigment changes in ocular tissues, 

including the retina, and also in the skin, lips and/or nails, as well as a distinct form of macular 
abnormality with features of vitelliform maculopathy; 

− The need for comprehensive ophthalmological examinations including visual acuity, slit-lamp 
examination, dilated fundus photography and macular optical coherence tomography (OCT) 
imaging at treatment initiation and at least every 6 months thereafter while treatment is 
ongoing. If retinal pigment, vitelliform maculopathy or vision changes are detected, treatment 
with Trobalt should only be continued after a careful re-assessment of the balance of benefits 
and risks. If continued, the patient should be monitored more closely. 

 

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80 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

ANNEX III 
 

LABELLING AND PACKAGE LEAFLET 

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81 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

A. LABELLING 

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PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER CARTON  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 50 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 50 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
21 film-coated tablets 
84 film-coated tablets 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/001 
EU/1/11/681/002 
 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 50 mg 
 

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MINIMUM PARTICULARS TO APPEAR ON BLISTERS OR STRIPS 
 
BLISTERS  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 50 mg film-coated tablets 
retigabine  
 
 
2. NAME OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
 
 
3. EXPIRY DATE 
 
EXP  
 
 
4. BATCH NUMBER 
 
Lot 
 
 
5. OTHER 
 

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85 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER CARTON  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 100 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 100 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
21 film-coated tablets 
84 film-coated tablets 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/004 
EU/1/11/681/005 
 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 100 mg 
 

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MINIMUM PARTICULARS TO APPEAR ON BLISTERS OR STRIPS 
 
BLISTERS  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 100 mg film-coated tablets 
retigabine  
 
 
2. NAME OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
 
 
3. EXPIRY DATE 
 
EXP  
 
 
4. BATCH NUMBER 
 
Lot 
 
 
5. OTHER 
 
 

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88 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER CARTON  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 200 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 200 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
84 film-coated tablets 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 
10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 

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11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/007 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 200 mg 
 

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90 

 
MINIMUM PARTICULARS TO APPEAR ON BLISTERS OR STRIPS 
 
BLISTERS  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 200 mg film-coated tablets 
retigabine  
 
 
2. NAME OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
 
 
3. EXPIRY DATE 
 
EXP  
 
 
4. BATCH NUMBER 
 
Lot 
 
 
5. OTHER 
 
 

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PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER CARTON  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 300 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 300 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
 
84 film-coated tablets 
 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/009 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 300 mg 
 

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MINIMUM PARTICULARS TO APPEAR ON BLISTERS OR STRIPS 
 
BLISTERS  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 300 mg film-coated tablets 
retigabine  
 
 
2. NAME OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
 
 
3. EXPIRY DATE 
 
EXP  
 
 
4. BATCH NUMBER 
 
Lot 
 
 
5. OTHER 
 
 

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94 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER CARTON  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 400 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 400 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
 
84 film-coated tablets 
 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/011 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 400 mg 
 

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MINIMUM PARTICULARS TO APPEAR ON BLISTERS OR STRIPS 
 
BLISTERS  
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 400 mg film-coated tablets 
retigabine  
 
 
2. NAME OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
 
 
3. EXPIRY DATE 
 
EXP  
 
 
4. BATCH NUMBER 
 
Lot 
 
 
5. OTHER 
 
 
 

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PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER LABEL (WITH BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 200 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 200 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
Multipack: 168 (2 packs of 84) film-coated tablets  
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 
 
10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 

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11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/008 
 
13. BATCH NUMBER 
 
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 

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99 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER LABEL (WITH BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 300 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 300 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
Multipack: 168 (2 packs of 84)film-coated tablets  
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 
10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 

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11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/010 
 
13. BATCH NUMBER 
 
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 

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101 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
OUTER LABEL (WITH BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 400 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 400 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
Multipack: 168 (2 packs of 84)film-coated tablets  
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 
10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 

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102 

 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/012 
 
13. BATCH NUMBER 
 
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
 

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PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
INTERMEDIATE CARTON (WITHOUT BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 200 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 200 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
84 film-coated tablets 
Component of a multipack, can’t  be sold separately 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/008 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 200 mg 
 

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105 

 
PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
INTERMEDIATE CARTON (WITHOUT BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 300 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 300 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
84 film-coated tablets 
Component of a multipack, can’t be sold separately 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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106 

10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/010 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 300 mg 
 

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PARTICULARS TO APPEAR ON THE OUTER PACKAGING 
 
INTERMEDIATE CARTON (WITHOUT BLUE BOX – MULTIPACK ONLY) 
 
 
1. NAME OF THE MEDICINAL PRODUCT 
 
Trobalt 400 mg film-coated tablets 
retigabine  
 
 
2. STATEMENT OF ACTIVE SUBSTANCE(S) 
 
Each tablet contains 400 mg retigabine 
 
 
3. LIST OF EXCIPIENTS 
 
 
 
4. PHARMACEUTICAL FORM AND CONTENTS 
 
84 film-coated tablets 
Component of a multipack, can’t  be sold separately 
 
 
5. METHOD AND ROUTE(S) OF ADMINISTRATION 
 
Read the package leaflet before use 
Oral use 
 
 
6. SPECIAL WARNING THAT THE MEDICINAL PRODUCT MUST BE STORED OUT 

OF THE SIGHT AND REACH OF CHILDREN 
 
Keep out of the sight and reach of children 
 
 
7. OTHER SPECIAL WARNING(S), IF NECESSARY 
 
 
 
8. EXPIRY DATE 
 
EXP  
 
 
9. SPECIAL STORAGE CONDITIONS 
 
 
 

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10. SPECIAL PRECAUTIONS FOR DISPOSAL OF UNUSED MEDICINAL PRODUCTS 
OR WASTE MATERIALS DERIVED FROM SUCH MEDICINAL PRODUCTS, IF 
APPROPRIATE 
 
 
11. NAME AND ADDRESS OF THE MARKETING AUTHORISATION HOLDER 
 
Glaxo Group Limited 
980 Great West Road,  
Brentford,  
Middlesex,  
TW8 9GS 
United Kingdom 
 
 
12. MARKETING AUTHORISATION NUMBER(S)  
 
EU/1/11/681/012 
 
13. BATCH NUMBER 
 
Lot  
 
 
14. GENERAL CLASSIFICATION FOR SUPPLY 
 
Medicinal product subject to medical prescription 
 
 
15. INSTRUCTIONS ON USE 
 
 
 
16. INFORMATION IN BRAILLE 
 
trobalt 400 mg 
 

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109 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

B. PACKAGE LEAFLET 
 

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Package leaflet: Information for the user 

 
Trobalt 50 mg film-coated tablets 

Trobalt 100 mg film-coated tablets 
Trobalt 200 mg film-coated tablets 
Trobalt 300 mg film-coated tablets 
Trobalt 400 mg film-coated tablets 

Retigabine 
 

 
Read all of this leaflet carefully before you start taking this medicine because it contains 
important information for you. 
• Keep this leaflet. You may need to read it again. 
• If you have any further questions, ask your doctor or pharmacist. 
• This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, 

even if their signs of illness are the same as yours. 
• If you get any side effects, talk to your doctor or pharmacist. This includes any possible side 

effects not listed in this leaflet. See section 4. 
 
 
What is in this leaflet 
 
1. What Trobalt is and what it is used for 
2. What you need to know before you take Trobalt 
3. How to take Trobalt 
4. Possible side effects 
5. How to store Trobalt 
6. Contents of the pack and other information 
 
 
1. What Trobalt is and what it is used for 
 
Trobalt contains the active substance retigabine. Trobalt is one of a group of medicines called 
antiepileptics. It works by preventing the brain overactivity that causes epileptic seizures (also called 
fits). 
 
Trobalt is used to treat seizures that affect one part of the brain (partial seizure), which may or may not 
extend to larger areas on both sides of the brain (secondary generalisation).  It is used together with 
other anti-epileptic medicines to treat adults who continue to experience seizures and where other 
combinations of antiepileptic medicines have not worked well. 
 
 
2. What you need to know before you take Trobalt 
 
Do not take Trobalt 

• if you are allergic to retigabine or any of the other ingredients of Trobalt (listed in section 6). 
 
Warnings and precautions 
Talk to your doctor before taking Trobalt: 

• if you are 65 years of age or above. 
• if you have kidney or liver problems.  

Tell your doctor if any of these applies to you. The doctor may decide to give you a reduced dose. 
 

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Look out for serious symptoms  
Trobalt can cause serious side effects, including an inability to pass urine (urinary retention) and 
mental health problems. You must look out for certain symptoms while you are taking Trobalt, to 
reduce the risk of any problems. See 'Look out for serious symptoms' in section 4. 
 
Discolouration of skin, nails, lips and eyes, and eye disorders caused by changes in the centre of the 
retina (maculopathy)  
Discolouration of parts of the eye, including the retina (inside the back of the eye) has been reported in 
people taking Trobalt for several years (see Section 4).  
Eye disorders caused by changes in the centre of the retina (maculopathy) have been reported in 
people taking Trobalt (see Section 4).  
 
Your doctor should recommend that you have an eye examination before starting treatment. The eye 
examination should be repeated at least every six months whilst taking Trobalt. Treatment will be 
stopped if any problems are found unless no other suitable treatments are available. Your doctor will 
monitor you more closely if treatment with Trobalt is continued. 
 
Tell your doctor if you experience any changes in vision whilst you are being treated with Trobalt. 
 
A blue-grey discolouration of the skin, lips or nails has also been reported in people taking Trobalt for 
several years (See Section 4). This sometimes occurs together with discolouration of parts of the eye.   
If you notice such changes while taking the medicine, tell your doctor. 
Your doctor will discuss with you whether treatment with Trobalt should be continued. 
 
Heart conditions 
Trobalt can affect heart rhythm. This is more likely to affect you: 

• if you are taking other medicines 
• if you have an existing heart problem 
• if you have low potassium (hypokalaemia) or low magnesium (hypomagnesaemia) in your 

blood.  
• if you are 65 years of age or above 
Tell your doctor if any of these apply to you, or if you notice any unusual changes in your heart 
beat (such as beating too fast or too slow). You may need extra check-ups (including an 
electrocardiogram [ECG], which is a test which records the electrical activity of your heart) while 
you are taking Trobalt. 

 
Thoughts of harming yourself or suicide 
A small number of people being treated with antiepileptics such as Trobalt have had thoughts of 
harming or killing themselves. If at any time you have these thoughts,  

Immediately contact your doctor. 
 
If you need a blood or urine test  
Trobalt can affect the results of some tests. If you need a blood or urine test: 

Tell the person who orders the test that you are taking Trobalt. 
 

Children and adolescents 
Trobalt is not recommended for children and adolescents aged under 18. The safety and efficacy are 
not yet known in this age group. 
 
Other medicines and Trobalt 
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other 
medicines. 
 
Trobalt may affect some anaesthetics (for example thiopental sodium). If you are going to have an 
operation under a general anaesthetic: 

Tell the doctor that you are taking Trobalt, well in advance.  

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Trobalt with alcohol 
Drinking alcohol with Trobalt can make your vision blurred.  Take extra care until you know how 
Trobalt and alcohol affect you. 
 
Pregnancy and breast-feeding 
There is no information about the safety of Trobalt in pregnant women. Therefore Trobalt is not 
recommended during pregnancy.You must use a reliable method of contraception to avoid becoming 
pregnant while you are being treated with Trobalt.  
 
If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask 
your doctor for advice before taking this medicine. Do not stop treatment without discussing it with 
your doctor. The doctor will weigh up the benefit to you against any risk to your baby of taking 
Trobalt while you are pregnant. 
 
It is not known whether the active substance of Trobalt can pass into breast-milk. 
Talk to your doctor about breast-feeding while you are taking Trobalt. Your doctor will weigh up the 
benefit to you against any risk to your baby of taking Trobalt while you are breast-feeding. 
 
Driving and using machines 
Trobalt can make you feel dizzy or drowsy and cause double or blurred vision. 
Don’t drive or use machines until you know how Trobalt affects you. 
 
You must talk to your doctor about the effect of your epilepsy on driving and using machines. 
 
 
3. How to take Trobalt 
 
Always take this medicine exactly as your doctor has told you to. Check with your doctor or 
pharmacist if you are not sure. 
 
How much to take  
The maximum starting dose of Trobalt is 100 mg, taken three times a day (a total of 300 mg a day). 
Your doctor may gradually adjust your dose over a few weeks so that your seizures are better 
controlled, and side effects are kept to a minimum. The maximum dose is 400 mg taken three times a 
day (a total of 1,200 mg a day). If you are over 65 years you will usually be given a reduced starting 
dose and your doctor may limit the maximum dose to 900 mg a day.  
 
If you have kidney or liver problems, your doctor may give you a reduced dose of Trobalt. 
 
Don’t take any more Trobalt than your doctor has recommended. It may take a few weeks to find the 
right dose of Trobalt for you. 
 
 
How to take 
Trobalt is for oral use. Swallow the tablet whole. Don’t chew, crush or split the tablet. You can take 
Trobalt with or without food. 
 
If you take more Trobalt than you should 
If you take too many tablets of Trobalt, you may be more likely to have side effects, or any of these 
symptoms: 

• feeling agitated, aggressive or irritable 
• effects on heart rhythm. 

Contact your doctor or pharmacist for advice if you ever take more Trobalt than you are 
prescribed. If possible, show them the medicine pack. 

 

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If you forget to take Trobalt 
If you miss any doses, just take one dose as soon as you remember. Then leave at least 3 hours before 
your next dose. 
Don't take more than one dose at a time to make up for missed doses. If you are not sure what to do, 
ask your doctor or pharmacist. 
 
Don’t stop taking Trobalt without advice 
Take Trobalt for as long as your doctor recommends. Don’t stop unless your doctor advises you to. 
 
If you stop taking Trobalt 
If you suddenly stop taking Trobalt, your seizures may come back or get worse. Do not reduce your 
dose unless your doctor tells you to. To stop taking Trobalt, it is important that the dose is reduced 
gradually, over at least 3 weeks. 
 
If you have any further questions on the use of this medicine, ask your doctor or pharmacist. 
 
4. Possible side effects 
 
Like all medicines, Trobalt can cause side effects, although not everybody gets them. 
 
Look out for serious symptoms 
 
Discolouration of parts of the eye, including the retina (inside the back of the eye): this can be 
very common in people taking Trobalt for several years.  
 
Eye disorders caused by changes in the centre of the retina (maculopathy): this can be common in 
people taking Trobalt. You may become aware of blurring of your central vision and notice trouble 
with reading or recognizing faces. At first, these changes might not affect your sight but, over time, it 
may get worse. 

In some cases changes to the pigmentation in the eyes may improve after you stop taking Trobalt. 
Your doctor should recommend that you have an eye examination before starting treatment. The eye 
examination should be repeated at least every six months whilst taking Trobalt. Treatment will be 
stopped if any problems are found unless no other suitable treatments are available. Your doctor will 
monitor you more closely if treatment with Trobalt is continued. 
 
A blue-grey discolouration of the skin, lips or nails: this is very common in people taking Trobalt 
for several years. This sometimes occur together with discolouration of parts of the eye. Your doctor 
will discuss with you whether treatment with Trobalt should be continued. 
 
Problems passing urine 
These are common in people taking Trobalt, and can lead to not being able to pass urine at all. This is 
most likely to happen during the first few months of treatment with Trobalt. Symptoms include: 

• pain when passing urine (dysuria) 
• difficulty in starting to urinate (urinary hesitation) 
• not being able to pass urine (urinary retention). 

Tell your doctor immediately if you get any of these symptoms. 
 

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114 

Mental health problems 
These are common in people taking Trobalt, and are most likely to happen during the first few months 
of treatment. Symptoms include: 

• confusion 
• psychotic disorders (severe mental health problems) 
• hallucinations (seeing or hearing things that are not there). 

Tell your doctor as soon as possible if you get any of these symptoms. Your doctor may decide 
that Trobalt is not suitable for you. 
 

 
Very common side effects 
These may affect more than 1 in 10 people: 

• dizziness 
• drowsiness 
• lack of energy. 

 
 
Common side effects 
These may affect up to 1 in 10 people: 

• blood in the urine; abnormally coloured urine 
• feeling disorientated; anxiety 
• memory problems (amnesia) 
• difficulty in reading, writing or saying what you mean, or difficulty in understanding words 
• attention problems 
• lack of co-ordination; spinning sensation (vertigo); balance problems; problems walking 
• tremors; sudden jerking of muscles (myoclonus) 
• tingling or numbness of the hands or feet 
• double or blurred vision 
• constipation; feeling sick (nausea); indigestion; dry mouth 
• weight gain; increased appetite 
• swelling of lower legs and feet 
• feeling weak or generally unwell 
• changes in liver function, which will show up in blood tests. 

 
Uncommon side effects 
These may affect up to 1 in 100 people: 

• slow or reduced muscle movement 
• difficulty in swallowing 
• skin rash 
• excessive sweating 
• kidney stones. 

 
 
Elderly 
If you are 65 years or older, you may be more likely than a younger adult to get the following 
symptoms:  

• drowsiness 
• memory problems 
• balance problems, lack of co-ordination, spinning sensation (vertigo), problems walking 
• tremors 

 
Reporting of side effects 
If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects 
not listed in this leaflet. You can also report side effects directly via the national reporting system 
listed in Appendix V. By reporting side effects you can help provide more information on the safety of 
this medicine. 

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115 

 
5. How to store Trobalt 
 
Keep out of the sight and reach of children. 
 
Do not use this medicine after the expiry date which is stated on the pack. The expiry date refers to the 
last day of that month. 
 
This medicine does not require any special storage conditions. 
 
Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to 
throw away medicines you no longer use. This will help protect the environment.  
 
6. Contents of the pack and other information 
 
What Trobalt contains 
The active substance is retigabine. Each tablet contains 50 mg, 100 mg, 200 mg, 300 mg or 400 mg 
retigabine. 
The other ingredients are: croscarmellose sodium, hypromellose, magnesium stearate, microcrystalline 
cellulose, polyvinyl alcohol, titanium dioxide (E171) , talc (E553b), Lecithin (SOY) and Xanthan 
gum. 
  
The 50 mg and 400 mg tablets also contain indigo carmine aluminium lake (E132) and carmine 
(E120).  
The 100 mg and 300 mg tablets also contain indigo carmine aluminium lake (E132) and iron oxide 
yellow (E172).  
The 200 mg tablets also contain iron oxide yellow (E172). 
 
What Trobalt looks like and contents of the pack 
Trobalt 50 mg film-coated tablets are purple, round and marked “RTG 50” on one side. Each pack 
contains blisters of 21or 84 film-coated tablets. 
 
Trobalt 100 mg film-coated tablets are green, round and marked “RTG 100” on one side. Each pack 
contains blisters of 21or 84  film-coated tablets. 
 
Trobalt 200 mg film-coated tablets are yellow, oblong and marked “RTG-200” on one side. Each pack 
contains blisters of 84 or 2 x 84 film-coated tablets. 
 
Trobalt 300 mg film-coated tablets are green, oblong and marked “RTG-300” on one side. Each pack 
contains blisters of 84 or 2 x 84 film-coated tablets. 
 
Trobalt 400 mg film-coated tablets are purple, oblong and marked “RTG-400” on one side. Each pack 
contains blisters of 84 or 2 x 84 film-coated tablets. 
 
Not all pack sizes may be available in your country. 
 
Marketing Authorisation Holder  
Glaxo Group Limited, 980 Great West Road, Brentford, Middlesex TW8 9GS United Kingdom. 
 
Manufacturer 
 
Glaxo Wellcome, S.A, Avda. Extremadura 3, 09400 Aranda De Duero, Burgos, Spain. 
 

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116 

For any information about this medicine, please contact the local representative of the Marketing 
Authorisation Holder: 
 
België/Belgique/Belgien 
GlaxoSmithKline Pharmaceuticals s.a./n.v. 
Tél/Tel: + 32 (0)10 85 52 00 

Luxembourg/Luxemburg 
GlaxoSmithKline Pharmaceuticals s.a./n.v. 
Belgique/Belgien 
Tél/Tel: + 32 (0)10 85 52 00 
 

България 
ГлаксоСмитКлайн ЕООД 
Teл.: + 359 2 953 10 34 
 

Magyarország 
GlaxoSmithKline Kft. 
Tel.: + 36 1 225 5300 

Česká republika 
GlaxoSmithKline s.r.o. 
Tel: + 420 222 001 111 
cz.info@gsk.com 
 

Malta 
GlaxoSmithKline (Malta) Limited 
Tel: + 356 21 238131 

Danmark 
GlaxoSmithKline Pharma A/S 
Tlf: + 45 36 35 91 00 
dk-info@gsk.com 
 

Nederland 
GlaxoSmithKline BV 
Tel: + 31 (0)30 6938100 
nlinfo@gsk.com 

Deutschland 
GlaxoSmithKline GmbH & Co. KG 
Tel.: + 49 (0)89 36044 8701 
produkt.info@gsk.com 
 

Norge 
GlaxoSmithKline AS 
Tlf: + 47 22 70 20 00 
firmapost@gsk.no 

Eesti 
GlaxoSmithKline Eesti OÜ 
Tel: + 372 6676 900 
estonia@gsk.com 
 

Österreich 
GlaxoSmithKline Pharma GmbH 
Tel: + 43 (0)1 97075 0 
at.info@gsk.com 
 

Ελλάδα 
GlaxoSmithKline A.E.B.E. 
Τηλ: + 30 210 68 82 100 

Polska 
GSK Services Sp. z o.o. 
Tel.: + 48 (0)22 576 9000 
 

España 
GlaxoSmithKline, S.A. 
Tel: + 34 902 202 700 
es-ci@gsk.com 
 

Portugal 
GlaxoSmithKline – Produtos Farmacêuticos, Lda. 
Tel: + 351 21 412 95 00 
FI.PT@gsk.com  
 

France 
Laboratoire GlaxoSmithKline 
Tél.: + 33 (0)1 39 17 84 44 
diam@gsk.com 
 

România 
GlaxoSmithKline (GSK) S.R.L.  
Tel: + 4021 3028 208 
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117 

 
Hrvatska 
GlaxoSmithKline d.o.o. 
Tel: + 385 1 6051999 
 

Slovenija 
GlaxoSmithKline d.o.o. 
Tel: + 386 (0)1 280 25 00 
medical.x.si@gsk.com 
 

Ireland 
GlaxoSmithKline (Ireland) Limited 
Tel: + 353 (0)1 4955000 
 

Slovenská republika 
GlaxoSmithKline Slovakia s. r. o. 
Tel: + 421 (0)2 48 26 11 11 
recepcia.sk@gsk.com 
 

Ísland 
Vistor hf.  
Sími: +354 535 7000 
 

Suomi/Finland 
GlaxoSmithKline Oy 
Puh/Tel: + 358 (0)10 30 30 30 
Finland.tuoteinfo@gsk.com 
 

Italia 
GlaxoSmithKline S.p.A. 
Tel: + 39 (0)45 9218 111 
 

Sverige 
GlaxoSmithKline AB 
Tel: + 46 (0)8 638 93 00 
info.produkt@gsk.com 

Κύπρος 
GlaxoSmithKline (Cyprus) Ltd 
Τηλ: + 357 22 39 70 00 
gskcyprus@gsk.com 

 
United Kingdom 
GlaxoSmithKline UK Ltd 
Tel: + 44 (0)800 221441 
customercontactuk@gsk.com  
 

Latvija 
GlaxoSmithKline Latvia SIA 
Tel: + 371 67312687 
lv-epasts@gsk.com 

 

 
Lietuva 
GlaxoSmithKline Lietuva UAB 
Tel: + 370 5 264 90 00 
info.lt@gsk.com 
 

 

 
 
This leaflet was last approved in 
 
Detailed information on this medicine is available on the European Medicines Agency web site: 
http://www.ema.europa.eu/. 

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118 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

ANNEX IV 
 

GROUNDS FOR ONE ADDITIONAL RENEWAL 
 

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119 

 
GROUDS FOR ONE ADDITIONAL RENEWAL 

Based upon the data that have become available since the granting of the initial Marketing 
Authorisation, the CHMP considers that the benefit-risk balance of Trobalt remains positive, but 
considers that its safety profile is to be closely monitored for the following reasons: 

Eye disorders have been observed with the use of Trobalt, including pigment changes in the retina. 
Uncertainties about the impact of this risk on patients remain as there is a possibility of functional 
abnormalities associated with retinopathy including potentially severe visual impairment. 

Therefore, based upon the safety profile of Trobalt the CHMP concluded that the MAH should 
submit one additional renewal application in 5 years. 

 
 

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	SUMMARY OF PRODUCT CHARACTERISTICS
	A. MANUFACTURER(S) RESPONSIBLE FOR BATCH RELEASE
	B. CONDITIONS OR RESTRICTIONS REGARDING SUPPLY AND USE
	C OTHER CONDITIONS AND REQUIREMENTS OF THE MARKETINGAUTHORISATION
	D. CONDITIONS OR RESTRICTIONS WITH REGARD TO THE SAFE ANDEFFECTIVE USE OF THE MEDICINAL PRODUCT
	A. LABELLING
	B. PACKAGE LEAFLET
	GROUDS FOR ONE ADDITIONAL RENEWAL