Hypotension/Syncope: Dopaminergic therapy in Parkinson's disease patients has been associated with orthostatic hypotension. Tolcapone enhances levodopa bioavailability and, therefore, may increase the occurrence of orthostatic hypotension. In tolcapone tablets clinical trials, orthostatic hypotension was documented at least once in 8%, 14% and 13% of the patients treated with placebo, 100 mg and 200 mg tolcapone tablets tid, respectively. A total of 2%, 5% and 4% of the patients treated with placebo, 100 mg and 200 mg tolcapone tablets tid, respectively, reported orthostatic symptoms at some time during their treatment and also had at least one episode of orthostatic hypotension documented (however, the episode of orthostatic symptoms itself was invariably not accompanied by vital sign measurements). Patients with orthostasis at baseline were more likely than patients without symptoms to have orthostatic hypotension during the study, irrespective of treatment group. In addition, the effect was greater in tolcapone-treated patients than in placebo-treated patients. Baseline treatment with dopamine agonists or selegiline did not appear to increase the likelihood of experiencing orthostatic hypotension when treated with tolcapone tablets. Approximately 0.7% of the patients treated with tolcapone tablets (5% of patients who were documented to have had at least one episode of orthostatic hypotension) eventually withdrew from treatment due to adverse events presumably related to hypotension.

In controlled Phase 3 trials, approximately 5%, 4% and 3% of tolcapone 200 mg tid, 100 mg tid and placebo patients, respectively, reported at least one episode of syncope. Reports of syncope were generally more frequent in patients in all three treatment groups who had an episode of documented hypotension (although the episodes of syncope, obtained by history, were themselves not documented with vital sign measurement) compared to patients who did not have any episodes of documented hypotension.

Diarrhea:In clinical trials, diarrhea developed in approximately 8%, 16% and 18% of patients treated with placebo, 100 mg and 200 mg tolcapone tablets tid, respectively. While diarrhea was generally regarded as mild to moderate in severity, approximately 3% to 4% of patients on tolcapone had diarrhea which was regarded as severe. Diarrhea was the adverse event which most commonly led to discontinuation, with approximately 1%, 5% and 6% of patients treated with placebo, 100 mg and 200 mg tolcapone tablets tid, respectively, withdrawing from the trials prematurely. Discontinuing tolcapone tablets for diarrhea was related to the severity of the symptom. Diarrhea resulted in withdrawal in approximately 8%, 40% and 70% of patients with mild, moderate and severe diarrhea, respectively. Although diarrhea generally resolved after discontinuation of tolcapone tablets, it led to hospitalization in 0.3%, 0.7% and 1.7% of patients in the placebo, 100 mg and 200 mg tolcapone tablets tid groups. 

Typically, diarrhea presents 6 to 12 weeks after tolcapone is started, but it may appear as early as 2 weeks and as late as many months after the initiation of treatment. Clinical trial data suggested that diarrhea associated with tolcapone use may sometimes be associated with anorexia (decreased appetite).

No consistent description of tolcapone-induced diarrhea has been derived from clinical trial data, and the mechanism of action is currently unknown.

It is recommended that all cases of persistent diarrhea should be followed up with an appropriate work-up (including occult blood samples).

Hallucinations / Psychotic Like Behavior: In clinical trials, hallucinations developed in approximately 5% of patients treated with placebo, compared to 8% and 10% of patients treated with 100 mg or 200 mg three times per day, respectively. Hallucinations led to drug discontinuation and premature withdrawal from clinical trials in 0.3% of patients treated with placebo, compared to 1.4% and 1.0% of patients treated with tolcapone tablets 100 mg or 200 mg tolcapone tablets three times per day, respectively. Hallucinations led to hospitalization in 0.0% of patients in the placebo group, compared to 1.7% and 0.0% of patients treated with 100 mg or 200 mg tolcapone tablets three times per day, respectively.

In general, hallucinations present shortly after the initiation of therapy with tolcapone (typically within the first 2 weeks). Clinical trial data suggest that hallucinations associated with tolcapone use may be responsive to levodopa dose reduction. Patients whose hallucinations resolved had a mean levodopa dose reduction of 175 mg to 200 mg (20% to 25%) after the onset of the hallucinations. Hallucinations were commonly accompanied by confusion and to a lesser extent sleep disorder (insomnia) and excessive dreaming. The incidence of hallucination may be increased in elderly patients over 75 years treated with tolcapone tablets [see Geriatric use].

Post-marketing reports indicate that patients may experience new or worsening mental status and behavioral changes, which may be severe, including psychotic-like behavior during tolcapone tablets treatment or after starting or increasing the dose of tolcapone tablets. Other drugs prescribed to improve the symptoms of Parkinson's disease may have similar effects on thinking and behavior. This abnormal thinking and behavior may present with one or more symptoms, including paranoid ideation, delusions, hallucinations, confusion, psychotic-like behavior, disorientation, aggressive behavior, agitation, and delirium.

Ordinarily, patients with a major psychotic disorder should not be treated with tolcapone tablets because of the risk of exacerbating psychosis. In addition, certain medications used to treat psychosis may exacerbate the symptoms of Parkinson's disease and may decrease the effectiveness of tolcapone tablets.

Dyskinesia:Tolcapone tablets may potentiate the dopaminergic side effects of levodopa and may cause and/or exacerbate preexisting dyskinesia. Although decreasing the dose of levodopa may ameliorate this side effect, many patients in controlled trials continued to experience frequent dyskinesias despite a reduction in their dose of levodopa. Dyskinesia was the most common adverse reaction observed in controlled trials and developed in approximately 20% of patients treated with placebo, compared to 42% and 51% of patients treated with tolcapone tablets 100 mg or 200 mg three times daily, respectively. The rates of withdrawal for dyskinesia were 0.0% in the placebo group, compared to 0.3% and 1.0% in the groups receiving tolcapone tablets 100 mg or 200 mg three times a day, respectively.

Impulse Control / Compulsive Behaviors:Reports suggest that patients may experience an intense urge to gamble, increased sexual urges, intense urges to spend money, binge eating, and/or other intense urges, and the inability to control these urges. These reports are associated with patients taking tolcapone tablets in conjunction with carbidopa/levodopa, as well as other medications that increase central dopaminergic tone and that are used to treat patients with Parkinson's disease. In some cases, although not all, these urges were reported to have stopped when the dose was reduced or the medication was discontinued. Because patients may not recognize these behaviors as abnormal, it is important for prescribers to specifically ask patients or their caregivers about the development of new or increased gambling urges, sexual urges, uncontrolled spending or other urges while being treated with tolcapone tablets. Physicians should consider dose reduction or stopping the medication if a patient develops such urges while taking tolcapone tablets [see Information for Patient].

Rhabdomyolysis:Cases of severe rhabdomyolysis, with one case of multi-organ system failure rapidly progressing to death, have been reported. The complicated nature of these cases makes it impossible to determine what role, if any, tolcapone tablets played in their pathogenesis. Severe prolonged motor activity including dyskinesia may account for rhabdomyolysis. Some cases, however, included fever, alteration of consciousness and muscular rigidity. It is possible, therefore, that the rhabdomyolysis may be a result of the syndrome described in Hyperpyrexia and Confusion (see PRECAUTIONS: Events Reported With Dopaminergic Therapy).

Renal Impairment:No dosage adjustment is needed in patients with mild to moderate renal impairment, however, patients with severe renal impairment should be treated with caution (see CLINICAL PHARMACOLOGY: Pharmacokinetics of Tolcapone and DOSAGE AND ADMINISTRATION).

Renal Toxicity:When rats were dosed daily for 1 or 2 years (exposures 6 times the human exposure or greater) there was a high incidence of proximal tubule cell damage consisting of degeneration, single cell necrosis, hyperplasia, karyocytomegaly and atypical nuclei. These effects were not associated with changes in clinical chemistry parameters, and there is no established method for monitoring for the possible occurrence of these lesions in humans. Although it has been speculated that these toxicities may occur as the result of a species-specific mechanism, experiments that would confirm the theory have not been conducted.

Hepatic Impairment:Because of the risk of liver injury, tolcapone tablets therapy should not be initiated in any patient with liver disease. For similar reasons, treatment should not be initiated in patients who have two SGPT/ALT or SGOT/AST values greater than the upper limit of normal (see BOXED WARNING) or any other evidence of hepatocellular dysfunction.

Hematuria:The rates of hematuria in placebo-controlled trials were approximately 2%, 4% and 5% in placebo, 100 mg and 200 mg tolcapone tablets tid, respectively. The etiology of the increase with Tolcapone tablets has not always been explained (for example, by urinary tract infection or warfarin therapy). In placebo-controlled trials in the United States (N=593) rates of microscopically confirmed hematuria were approximately 3%, 2% and 2% in placebo, 100 mg and 200 mg tolcapone tablets tid, respectively. 

Events Reported With Dopaminergic Therapy: The events listed below are known to be associated with the use of drugs that increase dopaminergic activity, although they are most often associated with the use of direct dopamine agonists. While cases of Hyperpyrexia and Confusion have been reported in association with tolcapone withdrawal (see paragraph below), the expected incidence of fibrotic complications is so low that even if tolcapone caused these complications at rates similar to those attributable to other dopaminergic therapies, it is unlikely that even a single example would have been detected in a cohort of the size exposed to tolcapone.

Hyperpyrexia and Confusion:In clinical trials, four cases of a symptom complex resembling the neuroleptic malignant syndrome (characterized by elevated temperature, muscular rigidity, and altered consciousness), similar to that reported in association with the rapid dose reduction or withdrawal of other dopaminergic drugs, have been reported in association with the abrupt withdrawal or lowering of the dose of tolcapone. In 3 of these cases, CPK was elevated as well. One patient died, and the other 3 patients recovered over periods of approximately 2, 4 and 6 weeks. Rare cases of this symptom complex have been reported during marketed use. It is difficult to determine if tolcapone tablets played a role in the pathogenesis of these events because these patients received several concomitant medications affecting the central nervous system such as monoaminergic (i.e., MAO-I, tricyclic and selective serotonin reuptake inhibitors) and anticholinergic agents.

Fibrotic Complications: Cases of retroperitoneal fibrosis, pulmonary infiltrates, pleural effusion, and pleural thickening have been reported in some patients treated with ergot derived dopaminergic agents. While these complications may resolve when the drug is discontinued, complete resolution does not always occur. Although these adverse events are believed to be related to the ergoline structure of these compounds, whether other, nonergot derived drugs (e.g., tolcapone) that increase dopaminergic activity can cause them is unknown. 

Three cases of pleural effusion, one with pulmonary fibrosis, occurred during clinical trials. These patients were also on concomitant dopamine agonists (pergolide or bromocriptine) and had a prior history of cardiac disease or pulmonary pathology (nonmalignant lung lesion).

Melanoma:Epidemiological studies have shown that patients with Parkinson's disease have a higher risk (2- to approximately 6-fold higher) of developing melanoma than the general population. Whether the increased risk observed was due to Parkinson's disease or other factors, such as drugs used to treat Parkinson's disease, is unclear.

For the reasons stated above, patients and providers are advised to monitor for melanomas frequently and on a regular basis when using tolcapone tablets for any indication. Ideally, periodic skin examination should be performed by appropriately qualified individuals (e.g., dermatologists).

Information for Patients: Patients should be instructed to take tolcapone tablets only as prescribed.

Tolcapone tablets should not be used by patients until there has been a complete discussion of the risks and the patient has provided written acknowledgement that the risks have been explained (see PATIENT ACKNOWLEDGEMENT OF RISKS section).

Inform patients about clinical signs and symptoms that suggest the onset of hepatic injury (persistent nausea, fatigue, lethargy, anorexia, jaundice, dark urine, pruritus, and right upper quadrant tenderness) (see WARNINGS). If symptoms of hepatic failure occur, patients should be advised to contact their physician immediately. 

Inform patients of the need to have regular blood tests to monitor liver enzymes. 

Advise patients that sleepiness or drowsiness may occur and that they should not drive a car or operate other complex machinery until they have gained sufficient experience on tolcapone tablets to gauge whether or not it adversely affects their mental and/or motor performance. Advise patients to exercise caution while driving, operating machines, or working at heights during treatment with tolcapone tablets. Because of the possible additive sedative effects, caution should also be used when patients are taking other CNS depressants in combination with tolcapone tablets. Inform patients that nausea may occur, especially at the initiation of treatment with tolcapone tablets.

Inform patients that hallucinations and other psychotic-like behavior may occur.

Advise patients about the possibility of developing or worsening of existing dyskinesia and/or dystonia after starting tolcapone tablets.

Advise patients that they may develop postural (orthostatic) hypotension with or without symptoms such as dizziness, nausea, syncope, and sometimes sweating. Advise patients to rise slowly, especially after long periods of sitting or lying down. Hypotension may be more likely when patients first start treatment with tolcapone tablets.

Instruct patients and caregivers to report intense urges to gamble, increased sexual urges, increase in spending money, binge eating, and other intense urges as well as the inability to control these urges to the prescriber while taking tolcapone tablets. 

Although tolcapone tablets has not been shown to be teratogenic in animals, it is always given in conjunction with levodopa/carbidopa, which is known to cause visceral and skeletal malformations in the rabbit. Accordingly, patients should be advised to notify their physicians if they become pregnant or intend to become pregnant during therapy (see PRECAUTIONS: Pregnancy).

Tolcapone is excreted into maternal milk in rats. Because of the possibility that tolcapone may be excreted into human milk, advise patients to notify their physicians if they intend to breastfeed or are breastfeeding an infant.

Laboratory Tests: Although a program of frequent laboratory monitoring for evidence of hepatocellular injury is deemed essential, it is not clear that periodic monitoring of liver enzymes will prevent the occurrence of fulminant liver failure. However, it is generally believed that early detection of drug-induced hepatic injury along with immediate withdrawal of the suspect drug enhances the likelihood for recovery. Accordingly, the following liver monitoring program is recommended.

Before starting treatment with tolcapone tablets, the physician should conduct appropriate tests to exclude the presence of liver disease. In patients determined to be appropriate candidates for treatment with tolcapone tablets, serum glutamic-pyruvic transaminase (SGPT/ALT) and serum glutamic-oxaloacetic transaminase (SGOT/AST) levels should be determined at baseline and periodically (i.e. every 2 to 4 weeks) for the first 6 months of therapy. After the first six months, periodic monitoring is recommended at intervals deemed clinically relevant. Although more frequent monitoring increases the chances of early detection, the precise schedule for monitoring is a matter of clinical judgment.

If the dose is increased to 200 mg tid (see DOSAGE AND ADMINISTRATION section), liver enzyme monitoring should take place before increasing the dose and then be conducted every 2 to 4 weeks for the following 6 months of therapy. After six months, periodic monitoring is recommended at intervals deemed clinically relevant.

Discontinue tolcapone tablets if SGPT/ALT or SGOT/AST levels exceed 2 times the upper limit of normal or if clinical signs and symptoms suggest the onset of hepatic dysfunction (e.g., persistent nausea, fatigue, lethargy, anorexia, jaundice, dark urine, pruritus, and right upper quadrant tenderness).

Special Populations: Tolcapone tablets therapy should not be initiated if the patient exhibits clinical evidence of active liver disease or two SGPT/ALT or SGOT/AST values greater than the upper limit of normal. Patients with severe dyskinesia or dystonia should be treated with caution (see PRECAUTIONS: Rhabdomyolysis). Patients with severe renal impairment should be treated with caution (see INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION, BOXED WARNING and WARNINGS).

Drug Interactions: Protein Binding: Although tolcapone is highly protein bound, in vitro studies have shown that tolcapone at a concentration of 50 mcg/mL did not displace other highly protein-bound drugs from their binding sites at therapeutic concentrations. The experiments included warfarin (0.5 to 7.2 mcg/mL), phenytoin (4.0 to 38.7 mcg/mL), tolbutamide (24.5 to 96.1 mcg/mL) and digitoxin (9.0 to 27.0 mcg/mL). 

Drugs Metabolized by Catechol-O-Methyltransferase (COMT): Tolcapone may influence the pharmacokinetics of drugs metabolized by COMT. However, no effects were seen on the pharmacokinetics of the COMT substrate carbidopa. The effect of tolcapone on the pharmacokinetics of other drugs of this class such as α-methyldopa, dobutamine, apomorphine, and isoproterenol has not been evaluated. A dose reduction of such compounds should be considered when they are co-administered with tolcapone.

Effect of Tolcapone on the Metabolism of Other Drugs: In vitro experiments have been performed to assess the potential of tolcapone to interact with isoenzymes of cytochrome P450 (CYP). No relevant interactions with substrates for CYP 2A6 (warfarin), CYP 1A2 (caffeine), CYP 3A4 (midazolam, terfenadine, cyclosporine), CYP 2C19 (S-mephenytoin) and CYP 2D6 (desipramine) were observed in vitro. The absence of an interaction with desipramine, a drug metabolized by cytochrome P450 2D6, was also confirmed in an in vivo study where tolcapone did not change the pharmacokinetics of desipramine.

Due to its affinity to cytochrome P450 2C9 in vitro, tolcapone may interfere with drugs, whose clearance is dependent on this metabolic pathway, such as tolbutamide and warfarin. However, in an in vivo interaction study, tolcapone did not change the pharmacokinetics of tolbutamide. Therefore, clinically relevant interactions involving cytochrome P450 2C9 appear unlikely. Similarly, tolcapone did not affect the pharmacokinetics of desipramine, a drug metabolized by cytochrome P450 2D6, indicating that interactions with drugs metabolized by that enzyme are unlikely. Since clinical information is limited regarding the combination of warfarin and tolcapone, coagulation parameters should be monitored when these two drugs are co-administered.

Drugs That Increase Catecholamines: Tolcapone did not influence the effect of ephedrine, an indirect sympathomimetic, on hemodynamic parameters or plasma catecholamine levels, either at rest or during exercise. Since tolcapone did not alter the tolerability of ephedrine, these drugs can be co-administered.

When tolcapone tablets was given together with levodopa/carbidopa and desipramine, there was no significant change in blood pressure, pulse rate and plasma concentrations of desipramine. Overall, the frequency of adverse events increased slightly. These adverse events were predictable based on the known adverse reactions to each of the three drugs individually. Therefore, caution should be exercised when desipramine is administered to Parkinson's disease patients being treated with tolcapone tablets and levodopa/carbidopa.

In clinical trials, patients receiving tolcapone tablets/levodopa preparations reported a similar adverse event profile independent of whether or not they were also concomitantly administered selegiline (a selective MAO-B inhibitor).

Carcinogenesis, Mutagenesis, Impairment of Fertility: Carcinogenesis: 

Carcinogenicity studies in which tolcapone was administered in the diet were conducted in mice and rats. Mice were treated for 80 (female) or 95 (male) weeks with doses of 100, 300 and 800 mg/kg/day, equivalent to 0.8, 1.6 and 4 times human exposure (AUC = 80 mcg•hr/mL) at the recommended daily clinical dose of 600 mg. Rats were treated for 104 weeks with doses of 50, 250 and 450 mg/kg/day. Tolcapone exposures were 1, 6.3 and 13 times the human exposure in male rats and 1.7, 11.8 and 26.4 times the human exposure in female rats. There was an increased incidence of uterine adenocarcinomas in female rats at exposure equivalent to 26.4 times the human exposure. There was evidence of renal tubular injury and renal tubular tumor formation in rats. A low incidence of renal tubular cell adenomas occurred in middle- and high-dose female rats; tubular cell carcinomas occurred in middle- and high-dose male and high-dose female rats, with a statistically significant increase in high-dose males. Exposures were equivalent to 6.3 (males) or 11.8 (females) times the human exposure or greater; no renal tumors were observed at exposures of 1 (males) or 1.7 (females) times the human exposure. Minimal-to-marked damage to the renal tubules, consisting of proximal tubule cell degeneration, single cell necrosis, hyperplasia and karyocytomegaly, occurred at the doses associated with renal tumors. Renal tubule damage, characterized by proximal tubule cell degeneration and the presence of atypical nuclei, as well as one adenocarcinoma in a high-dose male, were observed in a 1-year study in rats receiving doses of tolcapone of 150 and 450 mg/kg/day. These histopathological changes suggest the possibility that renal tumor formation might be secondary to chronic cell damage and sustained repair, but this relationship has not been established, and the relevance of these findings to humans is not known. There was no evidence of carcinogenic effects in the long-term mouse study. The carcinogenic potential of tolcapone in combination with levodopa/carbidopa has not been examined.

Mutagenesis: Tolcapone was clastogenic in the in vitro mouse lymphoma/thymidine kinase assay in the presence of metabolic activation. Tolcapone was not mutagenic in the Ames test, the in vitro V79/HPRT gene mutation assay, or the unscheduled DNA synthesis assay. It was not clastogenic in an in vitro chromosomal aberration assay in cultured human lymphocytes, or in an in vivo micronucleus assay in mice.

Impairment of Fertility: Tolcapone did not affect fertility and general reproductive performance in rats at doses up to 300 mg/kg/day (5.7 times the human dose on a mg/m2 basis).

Pregnancy: Pregnancy Category C. Tolcapone, when administered alone during organogenesis, was not teratogenic at doses of up to 300 mg/kg/day in rats or up to 400 mg/kg/day in rabbits (5.7 times and 15 times the recommended daily clinical dose of 600 mg, on a mg/m2 basis, respectively). In rabbits, however, an increased rate of abortion occurred at a dose of 100 mg/kg/day (3.7 times the daily clinical dose on a mg/m2 basis) or greater. Evidence of maternal toxicity (decreased weight gain, death) was observed at 300 mg/kg in rats and 400 mg/kg in rabbits. When tolcapone was administered to female rats during the last part of gestation and throughout lactation, decreased litter size and impaired growth and learning performance in female pups were observed at a dose of 250/150 mg/kg/day (dose reduced from 250 to 150 mg/kg/day during late gestation due to high rate of maternal mortality; equivalent to 4.8/2.9 times the clinical dose on a mg/m2 basis).

Tolcapone is always given concomitantly with levodopa/carbidopa, which is known to cause visceral and skeletal malformations in rabbits. The combination of tolcapone (100 mg/kg/day) with levodopa/carbidopa (80/20 mg/kg/day) produced an increased incidence of fetal malformations (primarily external and skeletal digit defects) compared to levodopa/carbidopa alone when pregnant rabbits were treated throughout organogenesis. Plasma exposures to tolcapone (based on AUC) were 0.5 times the expected human exposure, and plasma exposures to levodopa were 6 times higher than those in humans under therapeutic conditions. In a combination embryo-fetal development study in rats, fetal body weights were reduced by the combination of tolcapone (10, 30 and 50 mg/kg/day) and levodopa/carbidopa (120/30 mg/kg/day) and by levodopa/carbidopa alone. Tolcapone exposures were 0.5 times expected human exposure or greater: levodopa exposures were 21 times the expected human exposure or greater. The high dose of 50 mg/kg/day of tolcapone given alone was not associated with reduced fetal body weight (plasma exposures of 1.4 times the expected human exposure).

There is no experience from clinical studies regarding the use of tolcapone tablets in pregnant women. Therefore, tolcapone tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nursing Women: In animal studies, tolcapone was excreted into maternal rat milk.

It is not known whether tolcapone is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when tolcapone is administered to a nursing woman. 

Pediatric Use:There is no identified potential use of tolcapone in pediatric patients.

Geriatric Use: Parkinson's disease is primarily an affliction of the elderly. Consequently, the mean age of patients in tolcapone clinical trials was 60 to 65 years. To investigate safety as it relates to advancing age, three subgroups were identified: less than 65 years, 65 to 75 years, and greater than 75 years. There were generally no consistent age-related trends in safety parameters. However, patients greater than 75 years of age may be more likely to develop hallucinations than patients less than 75 years of age, while patients over 75 may be less likely to develop dystonia (see PRECAUTIONS: Hallucinations/Psychotic Like Behavior). In tolcapone clinical trials, measures of therapeutic efficacy (effects on "Off" time, levodopa dose, and effects on Activities of Daily Living) were not affected by age (see CLINICAL PHARMACOLOGY: Clinical studies). Tolcapone pharmacokinetics have not been found to be affected by age (see CLINICAL PHARMACOLOGY: Special Populations).