Vitamin C as add-on Therapy in Patients With Acute Herpes Zoster

Study Overview
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Brief Summary
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To compare the efficacy and tolerability of three different doses of Pascorbin® besides standard medication with placebo and the reduction of herpes zoster-associated clinical symptoms as an add-on therapy for patients suffering from acute herpes zoster in primary care

Official Title
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A Double-blind, Placebo-controlled, 4-arm Pilot Study on the Use of Vitamin C as Add on Therapy in Patients With Acute Herpes Zoster

Conditions
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Neuropathic Pain

Intervention / Treatment
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* Drug: Vitamin C


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female patients older than 18 years Diagnosis of acute herpes zoster Presence of at least one efflorescence Peak NRS pain score ≥ 5 within the last 24h Based on the appraisal of the investigator: adequate educational as well as intelligence level and communicative capacity in order to comply with the requirements of the trial Written informed consent of the patient Negative urine pregnancy test at the baseline visit (prior to the first infusion of study medication) for female patients of childbearing potential. Women of child-bearing potential must apply during the entire duration of the trial a highly effective method of birth control, which is defined as those which result in a low failure rate (i.e., less than 1 % per year) when used constantly and correctly such as implants, injectables, combined oral contraceptive method (oestrogen and progestogen), or some intrauterine devices (IUDs) or sexual abstinence (true abstinence, only if in line with the preferred and usual lifestyle) or vasectomy of partner. Women of non-childbearing potential may be included if surgically sterile (tubal ligation or hysterectomy) or post-menopausal with at least 1 year without spontaneous menses. Patients are suitable for study participation according to their general medical situation Exclusion Criteria: History of oxalate-urolithiasis or nephrolithiasis Current active zoster episode for more than 10 days Known severe renal function impairment consistent with Kidney Disease Improving Global Outcome (KDIGO) Glomerular Filtration Rate (GFR) stages G4 and 5 (< 30 ml/min/1.73m2) Known iron storage disease (e.g., thalassemia, hemochromatosis, sideroblastic anemia) Known erythrocytic glucose-6-phosphate dehydrogenase deficiency (at least class 3 = 10-60% rest activity = moderate deficiency) Prior vaccination with Zostavax® Signs or symptoms or diagnosed complications of herpes zoster such as zoster disseminatus, zoster generalisatus, zoster meningitis, zoster encephalitis, zoster myelitis, zoster pneumonitis, acute retinal necrosis (ARN) Contraindication to aciclovir treatment according to the current Summary of Product Characteristics (SmPC). Any disease that may interfere with the assessment of the course of the acute varicella zoster virus reactivation e.g. dermatological diseases such as psoriasis/eczema in the area of affected dermatomes painful local or systemic diseases such as wound infection or inflammation Immunodeficiency diseases, including but not limited to Human Immunodeficiency Virus (HIV) Known active malignancies other than non-melanoma skin cancer (NMSC) Severe uncontrolled diabetes mellitus, implanted insulin pump and severe respiratory obstructive diseases Other severe concomitant diseases with severe impairment of the patient's general condition History of additional herpes zoster in the last 3 months prior to baseline Any of the following medication, that might interact with the study medication or interfere with its effect Intravenous virostatics like aciclovir or brivudin within 4 weeks prior to baseline Oral virostatics like aciclovir or brivudin longer than 48 hours Any supplementary ascorbic acid (vitamin C) within 4 weeks prior to baseline Long-term analgesics (including local and transdermal) for non-Herpes pain (e.g. headache, rheumatism) Intake of any analgesics longer than 3 days for treatment of the current zoster symptoms Anticonvulsive drugs (gabapentin, pregabaline) within 4 weeks prior to baseline Antiepileptic drugs (carbamazepine) within 4 weeks prior to baseline Antidepressant drugs such as tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors (SSRI/SNRI) within 4 weeks prior to baseline Neuroleptics within 2 days prior to baseline Use of topical analgesics e.g., lidocaine or capsaicin patches on the site of the current herpes zoster efflorescence within 2 days prior to baseline Current therapy with immunosuppressive drugs, including but not limited to: Any systemic chemotherapeutics/cytostatic drugs Corticosteroids (> 5 mg/d prednisolone or equivalent) Methotrexate, ciclosporin, azathioprine Other drugs and interventions that may cause interactions with Vitamin C, including Fluphenazine Cumarine derivates Radiation therapy Nephrotoxic drugs, that may, according to the investigator's discretion, impair renal function Any other non-drug treatment of the acute herpes zoster Known hypersensitivity to the pharmacologic active constituents or any other ingredient of the study medication Participation in another clinical trial within the last 30 days prior to inclusion, simultaneous participation in another clinical trial or previous participation in this trial. Mental or physical disability or imprisonment

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Group 1 (control group)<br>300 ml NaCl infusion | Drug: Vitamin C<br>* Vitamin C<br>|
| Experimental: Group 2 (750 mg Vitamin C)<br>295 ml NaCl + 5 ml (750 mg) Vitamin C | Drug: Vitamin C<br>* Vitamin C<br>|
| Experimental: Group 3 (7.5 g Vitamin C)<br>250 ml NaCl + 1 x 50 ml (7.5 g) Vitamin C | Drug: Vitamin C<br>* Vitamin C<br>|
| Experimental: Group 4 (15 g Vitamin C)<br>200 ml NaCl + 2 x 50 ml (2 x 7.5 g) Vitamin C | Drug: Vitamin C<br>* Vitamin C<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean neuropathic pain | Area under the curve (AUC) of mean neuropathic pain measured by numeric rating scale (NRS) from baseline to V5 | from Baseline to V5 (day 11-13 after baseline) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of standard doses of permitted concomitant analgesic medication | Number of standard doses of permitted concomitant analgesic medication (step 1 of analgesic potency according to WHO) from baseline to V5 Step 1 (non-opioids: Paracetamol 500 mg, Ibuprofen 400 mg) | from Baseline to V5 (day 11-13 after baseline) | 
| AUC of equianalgesic doses of permitted concomitant analgesic medication | Area under the curve of equianalgesic doses of permitted concomitant analgesic medication (step 2 of analgesic potency according to WHO) from baseline to V5 Step 2 (weak opioids: Metamizole 500 mg, Tramadol 50 mg, Tilidine/Naloxone 50 mg/4 mg) | from Baseline to V5 (day 11-13 after baseline) | 
| Presence of a Post-herpetic neuralgia | Proportion of patient who developed a post-herpetic neuralgia at V7 | at V7 (day 90 (+/- 2 days)) |