Entacapone

Entacapone
Adult Indications & Dosage
Pediatric Indications & Dosage
Contraindications
Warnings & Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Administration & Monitoring
Overdosage
Pharmacology
Clinical Studies
How Supplied
Images
Patient Counseling Information
Precautions with Alcohol
Brand Names
Look-Alike Names

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rabin Bista, M.B.B.S. [2]

Disclaimer

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Overview

Entacapone is a Catechol-O-Methyltransferase Inhibitor that is FDA approved for the treatment of Parkinson’s Disease as an adjunct to levodopa and carbidopa therapy. Common adverse reactions include Dyskinesia, Urine Discoloration, Nausea, Diarrhea.

Adult Indications and Dosage

FDA-Labeled Indications and Dosage (Adult)

• Entacapone Tablets are indicated as an adjunct to levodopa and carbidopa to treat patients with idiopathic Parkinson’s Disease who experience the signs and symptoms of end-of-dose "wearing-off" .
• Entacapone Tablets’ effectiveness has not been systematically evaluated in patients with idiopathic Parkinson’s Disease who do not experience end-of-dose "wearing-off".

Off-Label Use and Dosage (Adult)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Entacapone in adult patients.

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Entacapone in adult patients.

Pediatric Indications and Dosage

FDA-Labeled Indications and Dosage (Pediatric)

There is limited information regarding FDA-Labeled Use of Entacapone in pediatric patients.

Off-Label Use and Dosage (Pediatric)

Guideline-Supported Use

There is limited information regarding Off-Label Guideline-Supported Use of Entacapone in pediatric patients.

Non–Guideline-Supported Use

There is limited information regarding Off-Label Non–Guideline-Supported Use of Entacapone in pediatric patients.

Contraindications

• Entacapone Tablets are contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients.

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 together 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, possibly 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.

Precautions

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 Entacapone Tablets clinical trials, however, no differences from placebo were seen for measured orthostasis or symptoms of orthostasis. Orthostatic hypotension was documented at least once in 2.7% and 3.0% of the patients treated with 200 mg Entacapone Tablets and placebo, respectively. A total of 4.3% and 4.0% of the patients treated with 200 mg Entacapone Tablets and placebo, 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 not accompanied by vital sign measurements). Neither baseline treatment with dopamine agonists or selegiline, nor the presence of orthostasis at baseline, increased the risk of orthostatic hypotension in patients treated with Entacapone Tablets compared to patients on placebo.

• In the large controlled trials, 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 (although the episodes of syncope, obtained by history, were themselves not documented with vital sign measurement).

Diarrhea and Colitis

• In clinical trials, diarrhea developed in 60 of 603 (10.0%) and 16 of 400 (4.0%) 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 with weight loss, dehydration, and hypokalemia.

• Postmarketing experience has shown that diarrhea may be a sign of drug-induced microscopic colitis, primarily lymphocytic colitis. In these cases diarrhea has usually been moderate to severe, watery, and non-bloody, at times associated with dehydration, abdominal pain, weight loss, and hypokalemia. In the majority of cases, diarrhea and other colitis-related symptoms resolved or significantly improved when Entacapone Tablets treatment was stopped. In some patients with biopsy confirmed colitis, diarrhea had resolved or significantly improved after discontinuation of Entacapone Tablets but recurred after retreatment with Entacapone Tablets.

• If prolonged diarrhea is suspected to be related to Entacapone Tablets, the drug should be discontinued and appropriate medical therapy considered. If the cause of prolonged diarrhea remains unclear or continues after stopping entacapone, then further diagnostic investigations including colonoscopy and biopsies should be considered.

Hallucinations

• Dopaminergic therapy in Parkinson’s Disease patients has been associated with hallucinations. In clinical trials, hallucinations developed in approximately 4.0% of patients treated with 200 mg Entacapone Tablets or placebo. Hallucinations led to drug discontinuation and premature withdrawal from clinical trials 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.

Dyskinesia

• Entacapone 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. The rates of withdrawal for dyskinesia were 1.5% and 0.8% for 200 mg Entacapone Tablets and placebo, respectively.

Other Events Reported With Dopaminergic Therapy

• The events listed below are rare events 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.

Rhabdomyolysis

• Cases of severe rhabdomyolysis have been reported with Entacapone Tablets use. The complicated nature of these cases makes it impossible to determine what role, if any, Entacapone Tablets played in their pathogenesis. Severe prolonged motor activity including dyskinesia may account for rhabdomyolysis. One case, however, included fever and alteration of consciousness. It is therefore possible that the rhabdomyolysis may be a result of the syndrome described in Hyperpyrexia and Confusion.

Hyperpyrexia and Confusion

• Cases of a symptom complex resembling the neuroleptic malignant syndrome characterized by elevated temperature, muscular rigidity, altered consciousness, and elevated CPK have been reported in association with the rapid dose reduction or withdrawal of other dopaminergic drugs. Several cases with similar signs and symptoms have been reported in association with Entacapone Tablets therapy, although no information about dose manipulation is available. The complicated nature of these cases makes it difficult to determine what role, if any, Entacapone Tablets may have played in their pathogenesis. No cases have been reported following the abrupt withdrawal or dose reduction of entacapone treatment during clinical studies.

• Prescribers should exercise caution when discontinuing entacapone treatment. When considered necessary, withdrawal should proceed slowly. If a decision is made to discontinue treatment with Entacapone Tablets, recommendations include monitoring the patient closely and adjusting other dopaminergic treatments as needed. This syndrome should be considered in the differential diagnosis for any patient who develops a high fever or severe rigidity. Tapering Entacapone Tablets has not been systematically evaluated.

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. These complications may resolve when the drug is discontinued, but 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., entacapone) that increase dopaminergic activity can cause them is unknown. It should be noted that the expected incidence of fibrotic complications is so low that even if entacapone caused these complications at rates similar to those attributable to other dopaminergic therapies, it is unlikely that it would have been detected in a cohort of the size exposed to entacapone. Four cases of pulmonary fibrosis were reported during clinical development of entacapone; three of these patients were also treated with pergolide and one with bromocriptine. The duration of treatment with entacapone ranged from 7 months to 17 months.

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 Entacapone Tablets for any indication. Ideally, periodic skin examination should be performed by appropriately qualified individuals (e.g., dermatologists).

Renal Toxicity

• In a 1 year toxicity study, entacapone (plasma exposure 20 times that in humans receiving the maximum recommended daily dose of 1,600 mg) caused an increased incidence in male rats of nephrotoxicity that was characterized by regenerative tubules, thickening of basement membranes, infiltration of mononuclear cells and tubular protein casts. 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 this toxicity could represent a species-specific effect, there is not yet evidence that this is so.

Hepatic Impairment

• Patients with hepatic impairment should be treated with caution. The AUC and Cmax of entacapone approximately doubled in patients with documented liver disease compared to controls.

Laboratory Tests

• Entacapone Tablets is a chelator of iron. The impact of entacapone on the body’s iron stores is unknown; however, a tendency towards decreasing serum iron concentrations was noted in clinical trials. In a controlled clinical study serum ferritin levels (as marker of iron deficiency and subclinical anemia) were not changed with entacapone compared to placebo after one year of treatment and there was no difference in rates of anemia or decreased hemoglobin levels.

Adverse Reactions

Clinical Trials Experience

• During the pre-marketing development of entacapone, 1,450 patients with Parkinson’s Disease were treated with entacapone. 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 events (greater than 5%) in the double-blind, placebo-controlled trials (N=1,003) associated with the use of Entacapone Tablets and not seen at an equivalent frequency among the placebo-treated patients were: dyskinesia and hyperkinesia, nausea, urine discoloration, diarrhea, and abdominal pain.

• Approximately 14% of the 603 patients given entacapone in the double-blind, placebo-controlled trials discontinued treatment due to adverse events compared to 9% of the 400 patients who received placebo. The most frequent causes of discontinuation in decreasing order are: psychiatric reasons (2% vs. 1%), diarrhea (2% vs. 0%), dyskinesia and hyperkinesia (2% vs. 1%), nausea (2% vs. 1%), abdominal pain (1% vs. 0%), and aggravation of Parkinson’s Disease symptoms (1% vs. 1%).

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 group, compared to placebo. In these studies, either entacapone 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

Postmarketing Experience

There is limited information regarding Postmarketing Experience of Entacapone in the drug label.

Body as a Whole

Cardiovascular

Digestive

Endocrine

Hematologic and Lymphatic

Metabolic and Nutritional

Musculoskeletal

Neurologic

Respiratory

Skin and Hypersensitivy Reactions

Special Senses

Urogenital

Miscellaneous

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.

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)

• When a single 400 mg dose of entacapone was given together 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, possibly 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.

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 Parkinson’s Disease patients in clinical trials 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.

Use in Specific Populations

Pregnancy

Pregnancy Category (FDA): C

• Pregnancy Category
• In embryofetal development studies, entacapone was administered to pregnant animals throughout organogenesis at doses of up to 1,000 mg per kg per day in rats and 300 mg per kg per day in rabbits. Increased incidences of fetal variations were evident in litters from rats treated with the highest dose, in the absence of overt signs of maternal toxicity. The maternal plasma drug exposure (AUC) associated with this dose was approximately 34 times the estimated plasma exposure in humans receiving the maximum recommended daily dose (MRDD) of 1,600 mg. Increased frequencies of abortions and late and total resorptions and decreased fetal weights were observed in the litters of rabbits treated with maternotoxic doses of 100 mg per kg per day (plasma AUCs 0.4 times those in humans receiving the MRDD) or greater. There was no evidence of teratogenicity in these studies.

However, when entacapone was administered to female rats prior to mating and during early gestation, an increased incidence of fetal eye anomalies (macrophthalmia, microphthalmia, anophthalmia) was observed in the litters of dams treated with doses of 160 mg per kg per day (plasma AUCs 7 times those in humans receiving the MRDD) or greater, in the absence of maternotoxicity. Administration of up to 700 mg per kg per day (plasma AUCs 28 times those in humans receiving the MRDD) to female rats during the latter part of gestation and throughout lactation, produced no evidence of developmental impairment in the offspring.

Entacapone is always given concomitantly with levodopa and carbidopa, which is known to cause visceral and skeletal malformations in rabbits. The teratogenic potential of entacapone in combination with levodopa and carbidopa was not assessed in animals.

There is no experience from clinical studies regarding the use of Entacapone Tablets in pregnant women. Therefore, Entacapone Tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Pregnancy Category (AUS):

• Australian Drug Evaluation Committee (ADEC) Pregnancy Category

There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Entacapone in women who are pregnant.

Labor and Delivery

There is no FDA guidance on use of Entacapone during labor and delivery.

Nursing Mothers

• In animal studies, entacapone was excreted into maternal rat milk.

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

Pediatric Use

• There is no identified potential use of entacapone in pediatric patients.

Geriatic Use

There is no FDA guidance on the use of Entacapone with respect to geriatric patients.

Gender

There is no FDA guidance on the use of Entacapone with respect to specific gender populations.

Race

There is no FDA guidance on the use of Entacapone with respect to specific racial populations.

Renal Impairment

• In a 1 year toxicity study, entacapone (plasma exposure 20 times that in humans receiving the maximum recommended daily dose of 1,600 mg) caused an increased incidence in male rats of nephrotoxicity that was characterized by regenerative tubules, thickening of basement membranes, infiltration of mononuclear cells and tubular protein casts. 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 this toxicity could represent a species-specific effect, there is not yet evidence that this is so.

Hepatic Impairment

• Patients with hepatic impairment should be treated with caution. The AUC and Cmax of entacapone approximately doubled in patients with documented liver disease compared to controls.

Females of Reproductive Potential and Males

There is no FDA guidance on the use of Entacapone in women of reproductive potentials and males.

Immunocompromised Patients

There is no FDA guidance one the use of Entacapone in patients who are immunocompromised.

Administration and Monitoring

Administration

• Oral

• Intravenous

Monitoring

There is limited information regarding Monitoring of Entacapone in the drug label.

• Description

IV Compatibility

There is limited information regarding IV Compatibility of Entacapone in the drug label.

Overdosage

Acute Overdose

Signs and Symptoms

• Description

Management

• Description

Chronic Overdose

There is limited information regarding Chronic Overdose of Entacapone in the drug label.

Pharmacology

There is limited information regarding Entacapone Pharmacology in the drug label.

Mechanism of Action

Structure

File:Entacapone01.png

This image is provided by the National Library of Medicine.

Pharmacodynamics

There is limited information regarding Pharmacodynamics of Entacapone in the drug label.

Pharmacokinetics

There is limited information regarding Pharmacokinetics of Entacapone in the drug label.

Nonclinical Toxicology

Carcinogenesis

Two-year carcinogenicity studies of entacapone were conducted in mice and rats. Rats were treated once daily by oral gavage with entacapone doses of 20 mg per kg, 90 mg per kg, or 400 mg per kg. An increased incidence of renal tubular adenomas and carcinomas was found in male rats treated with the highest dose of entacapone. Plasma exposures (AUC) associated with this dose were approximately 20 times higher than estimated plasma exposures of humans receiving the maximum recommended daily dose of entacapone (MRDD = 1,600 mg). Mice were treated once daily by oral gavage with doses of 20 mg per kg, 100 mg per kg or 600 mg per kg of entacapone (0.05, 0.3, and 2 times the MRDD for humans on a mg per m2 basis). Because of a high incidence of premature mortality in mice receiving the highest dose of entacapone, the mouse study is not an adequate assessment of carcinogenicity. Although no treatment related tumors were observed in animals receiving the lower doses, the carcinogenic potential of entacapone has not been fully evaluated. The carcinogenic potential of entacapone administered in combination with levodopa and carbidopa has not been evaluated.

Mutagenesis Entacapone was mutagenic and clastogenic in the in vitro mouse lymphoma and thymidine kinase assay in the presence and absence of metabolic activation, and was clastogenic in cultured human lymphocytes in the presence of metabolic activation. Entacapone, either alone or in combination with levodopa and carbidopa, was not clastogenic in the in vivo mouse micronucleus test or mutagenic in the bacterial reverse mutation assay (Ames test).

Impairment of Fertility

• Entacapone did not impair fertility or general reproductive performance in rats treated with up to 700 mg per kg per day (plasma AUCs 28 times those in humans receiving the MRDD). Delayed mating, but no fertility impairment, was evident in female rats treated with 700 mg per kg per day of entacapone.

Clinical Studies

There is limited information regarding Clinical Studies of Entacapone in the drug label.

How Supplied

Storage

There is limited information regarding Entacapone Storage in the drug label.

Images

Drug Images

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Package and Label Display Panel

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Patient Counseling Information

There is limited information regarding Patient Counseling Information of Entacapone in the drug label.

Precautions with Alcohol

• Alcohol-Entacapone interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.

Brand Names

• ®

Look-Alike Drug Names

• A® — B®

Drug Shortage Status

Price

References

The contents of this FDA label are provided by the National Library of Medicine.

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