Entacapone 200 mg Tablet, 100-count — NDC 33342-260-11 (Billing 33342-0260-11)

WARNINGS Monoamine oxidase (MAO) and COMT are the two major enzyme systems involved in the metabolism of catecholamines. It is theoretically possible, therefore, that the combination of entacapone tablets and a non-selective MAO inhibitor (e.g., phenelzine and tranylcypromine) would result in inhibition of the majority of the pathways responsible for normal catecholamine metabolism. For this reason, patients should ordinarily not be treated concomitantly with entacapone tablets and a non-selective MAO inhibitor.

Entacapone can be taken concomitantly with a selective MAO-B inhibitor (e.g., selegiline). Drugs Metabolized By Catechol-O-Methyltransferase (COMT) When a single 400 mg dose of entacapone was given with intravenous isoprenaline (isoproterenol) and epinephrine without coadministered levodopa and dopa decarboxylase inhibitor, the overall mean maximal changes in heart rate during infusion were about 50% and 80% higher than with placebo, for isoprenaline and epinephrine, respectively. Therefore, drugs known to be metabolized by COMT, such as isoproterenol, epinephrine, norepinephrine, dopamine, dobutamine, alpha-methyldopa, apomorphine, isoetherine, and bitolterol should be administered with caution in patients receiving entacapone regardless of the route of administration (including inhalation), as their interaction may result in increased heart rates, possible arrhythmias, and excessive changes in blood pressure.

Ventricular tachycardia was noted in one 32-year-old healthy male volunteer in an interaction study after epinephrine infusion and oral entacapone administration. Treatment with propranolol was required. A causal relationship to entacapone administration appears probable but cannot be attributed with certainty.

Falling Asleep During Activities of Daily Living and Somnolence Patients with Parkinson’s disease treated with entacapone tablets, which increases plasma levodopa levels, or with levodopa have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living (including the operation of motor vehicles). Some of these episodes resulted in accidents. Although many of these patients reported somnolence while on entacapone tablets, some did not perceive warning signs, such as excessive drowsiness, and believed that they were alert immediately prior to the event.

Some of these events have been reported as late as one year after initiation of treatment. The risk of somnolence was increased (entacapone 2% and placebo 0%) in controlled studies. It has been reported that falling asleep while engaged in activities of daily living always occurs in a setting of preexisting somnolence, although patients may not give such a history.

For this reason, prescribers should reassess patients for drowsiness or sleepiness especially since some of the events occur well after the start of treatment. Prescribers should also be aware that patients may not acknowledge drowsiness or sleepiness until directly questioned about drowsiness or sleepiness during specific activities. Patients should be advised to exercise caution while driving, operating machines, or working at heights during treatment with entacapone tablets.

Patients who have already experienced somnolence and/or an episode of sudden sleep onset should not participate in these activities during treatment with entacapone tablets. Before initiating treatment with entacapone tablets, advise patients of the potential to develop drowsiness and specifically ask about factors that may increase this risk such as concomitant use of sedating medications and the presence of sleep disorders. If a patient develops daytime sleepiness or episodes of falling asleep during activities that require active participation (e.g., conversations, eating, etc.), entacapone tablets should ordinarily be discontinued (see DOSAGE AND ADMINISTRATION for guidance on discontinuing entacapone tablets).

If the decision is made to continue entacapone tablets, p… [Excerpted — this section continues on DailyMed.]

ADVERSE REACTIONS Because clinical studies are conducted under widely varying conditions, the incidence of adverse reactions (number of unique patients experiencing an adverse reaction associated with treatment per total number of patients treated) observed in the clinical studies of a drug cannot be directly compared to the incidence of adverse reactions in the clinical studies of another drug and may not reflect the incidence of adverse reactions observed in practice. A total of 1,450 patients with Parkinson’s disease were treated with entacapone tablets in premarketing clinical studies.

Included were patients with fluctuating symptoms, as well as those with stable responses to levodopa therapy. All patients received concomitant treatment with levodopa preparations, however, and were similar in other clinical aspects. The most commonly observed adverse reactions (incidence at least 3% greater than placebo) in double-blind, placebo-controlled studies (N=1,003) associated with the use of entacapone tablets were: dyskinesia, urine discoloration, diarrhea, nausea, hyperkinesia, abdominal pain, vomiting, and dry mouth.

Approximately 14% of the 603 patients given entacapone in the double-blind, placebo-controlled studies discontinued treatment due to adverse reactions, compared to 9% of the 400 patients who received placebo. The most frequent causes of discontinuation in decreasing order were: psychiatric disorders (2% vs. 1%), diarrhea (2% vs.

0%), dyskinesia and hyperkinesia (2% vs. 1%), nausea (2% vs. 1%), and abdominal pain (1% vs.

0%). Adverse Event Incidence in Controlled Clinical Studies Table 4 lists treatment-emergent adverse events that occurred in at least 1% of patients treated with entacapone participating in the double-blind, placebo-controlled studies and that were numerically more common in the entacapone tablets group, compared to placebo. In these studies, either entacapone tablets or placebo was added to levodopa and carbidopa (or levodopa and benserazide).

Table 4: Summary of Patients with Adverse Events after Start of Trial Drug Administration At least 1% in Entacapone Tablet Group and Greater Than Placebo SYSTEM ORGAN CLASS Preferred term Entacapone (n = 603) % of patients Placebo (n = 400) % of patients SKIN AND APPENDAGES DISORDERS Sweating increased 2 1 MUSCULOSKELETAL SYSTEM DISORDERS Back pain 2 1 CENTRAL AND PERIPHERAL NERVOUS SYSTEM DISORDERS Dyskinesia Hyperkinesia Hypokinesia Dizziness 25 10 9 8 15 5 8 6 SPECIAL SENSES, OTHER DISORDERS Taste perversion 1 0 PSYCHIATRIC DISORDERS Anxiety Somnolence Agitation 2 2 1 1 0 0 GASTROINTESTINAL SYSTEM DISORDERS Nausea Diarrhea Abdominal pain Constipation Vomiting Mouth dry Dyspepsia Flatulence Gastritis Gastrointestinal disorders 14 10 8 6 4 3 2 2 1 1 8 4 4 4 1 0 1 0 0 0 RESPIRATORY SYSTEM DISORDERS Dyspnea 3 1 PLATELET, BLEEDING AND CLOTTING DISORDERS Purpura 2 1 URINARY SYSTEM DISORDERS Urine discoloration 10 0 BODY AS A WHOLE - GENERAL DISORDERS Back pain Fatigue Asthenia 4 6 2 2 4 1 RESISTANCE MECHANISM DISORDERS Infection bacterial 1 0 Effects of Gender and Age on Adverse Reactions No differences were noted in the rate of adverse events attributable to entacapone by age or gender.

Postmarketing Reports The following spontaneous reports of adverse events temporally associated with entacapone tablets have been identified since market introduction and are not listed in Table 4. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish causal relationship to entacapone tablets exposure. Hepatitis with mainly cholestatic features has been reported.

Drug Interactions In vitro studies of human CYP enzymes showed that entacapone inhibited the CYP enzymes 1A2, 2A6, 2C9, 2C19, 2D6, 2E1 and 3A only at very high concentrations (IC50 from 200 microM to over 1,000 microM; an oral 200 mg dose achieves a highest level of approximately 5 microM in people); these enzymes would therefore not be expected to be inhibited in clinical use. In an interaction study in healthy volunteers, entacapone did not significantly change the plasma levels of S-warfarin while the AUC for R-warfarin increased on average by 18% [Cl90 11% to 26%], and the INR values increased on average by 13% [Cl90 6% to 19%].

Nevertheless, cases of significantly increased INR in patients concomitantly using warfarin have been reported during the postapproval use of entacapone tablets. Therefore, monitoring of INR is recommended when entacapone treatment is initiated or when the dose is increased for patients receiving warfarin. Protein Binding Entacapone is highly protein bound (98%).

In vitro studies have shown no binding displacement between entacapone and other highly bound drugs, such as warfarin, salicylic acid, phenylbutazone, and diazepam. Drugs Metabolized by Catechol-O-Methyltransferase (COMT) See WARNINGS. Hormone Levels Levodopa is known to depress prolactin secretion and increase growth hormone levels.

Treatment with entacapone coadministered with levodopa and dopa decarboxylase inhibitor does not change these effects. Effect of Entacapone on the Metabolism of Other Drugs See WARNINGS regarding concomitant use of entacapone tablets and non-selective MAO inhibitors. No interaction was noted with the MAO-B inhibitor selegiline in two multiple-dose interaction studies when entacapone was coadministered with a levodopa and dopa decarboxylase inhibitor (n=29).

More than 600 patients with Parkinson’s disease in clinical studies have used selegiline in combination with entacapone and levodopa and dopa decarboxylase inhibitor. As most entacapone excretion is via the bile, caution should be exercised when drugs known to interfere with biliary excretion, glucuronidation, and intestinal beta-glucuronidase are given concurrently with entacapone. These include probenecid, cholestyramine, and some antibiotics (e.g., erythromycin, rifampicin, ampicillin, and chloramphenicol).

No interaction with the tricyclic antidepressant imipramine was shown in a single-dose study with entacapone without coadministered levodopa and dopa-decarboxylase inhibitor.

PRECAUTIONS Hypotension, Orthostatic Hypotension, and Syncope Dopaminergic therapy in Parkinson’s disease patients has been associated with orthostatic hypotension. Entacapone enhances levodopa bioavailability and, therefore, might be expected to increase the occurrence of orthostatic hypotension. In controlled studies, approximately 1.2% and 0.8% of 200 mg entacapone and placebo patients, respectively, reported at least one episode of syncope.

Reports of syncope were generally more frequent in patients in both treatment groups who had an episode of documented hypotension. Hallucinations and Psychotic-Like Behavior Dopaminergic therapy in patients with Parkinson’s disease has been associated with hallucinations. In clinical studies, hallucinations led to drug discontinuation and premature withdrawal in 0.8% and 0% of patients treated with 200 mg entacapone tablets and placebo, respectively.

Hallucinations led to hospitalization in 1.0% and 0.3% of patients in the 200 mg entacapone tablets and placebo groups, respectively. Agitation occurred in 1% of patients treated with entacapone tablets and 0% treated with placebo. Postmarketing reports indicate that patients may experience new or worsening mental status and behavioral changes, which may be severe, including psychotic-like behavior during entacapone tablets treatment or after starting or increasing the dose of entacapone tablets.

Other drugs prescribed to improve the symptoms of Parkinson’s disease can have similar effects on thinking and behavior. Abnormal thinking and behavior can cause paranoid ideation, delusions, hallucinations, confusion, disorientation, aggressive behavior, agitation, and delirium. Psychotic-like behaviors were also observed during the clinical development of entacapone tablets.

Patients with a major psychotic disorder should ordinarily not be treated with entacapone 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 entacapone tablets (see PRECAUTIONS). Impulse Control and Compulsive Behaviors Postmarketing reports suggest that patients treated with anti-Parkinson medications can experience intense urges to gamble, increased sexual urges, intense urges to spend money uncontrollably, and other intense urges.

Patients may be unable to control these urges while taking one or more of the medications that are used for the treatment of Parkinson’s disease and that increase central dopaminergic tone, including entacapone tablets taken with levodopa and carbidopa. In some cases, although not all, these urges were reported to have stopped when the dose of anti-Parkinson medications was reduced or 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 entacapone.

Physicians should consider dose reduction or stopping entacapone tablets if a patient develops such urges while taking entacapone tablets. Diarrhea and Colitis In clinical studies, diarrhea developed in 60 of 603 (10%) and 16 of 400 (4%) of patients treated with 200 mg entacapone tablets and placebo, respectively. In patients treated with entacapone tablets, diarrhea was generally mild to moderate in severity (8.6%) but was regarded as severe in 1.3%.

Diarrhea resulted in withdrawal in 10 of 603 (1.7%) patients, 7 (1.2%) with mild and moderate diarrhea and 3 (0.5%) with severe diarrhea. Diarrhea generally resolved after discontinuation of entacapone tablets. Two patients with diarrhea were hospitalized.

Typically, diarrhea presents within 4 weeks to 12 weeks after entacapone is started, but it may appear as early as the first week and as late as many months after the initiation of treatment. Diarrhea may be associated wi… [Excerpted — this section continues on DailyMed.]

DRUG ABUSE AND DEPENDENCE Entacapone tablets are not a controlled substance. Animal studies to evaluate the drug abuse and potential dependence have not been conducted. Although clinical studies have not revealed any evidence of the potential for abuse, tolerance or physical dependence, systematic studies in humans designed to evaluate these effects have not been performed.