ENTACAPONE 200 mg Tablet, Film Coated, 100-count
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Catechol-O-Methyltransferase Inhibitor class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Entacapone is an inhibitor of catechol-O-methyltransferase (COMT). It is used in combination with levodopa and carbidopa (Sinemet) to treat the end-of-dose 'wearing-off' symptoms of Parkinson's disease. Entacapone helps the levodopa and carbidopa work better by allowing more of it to reach the brain, where it has its effects. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
Read the full MedlinePlus article ↗- Entacapone works by blocking an enzyme that breaks down levodopa in your body, but its effect only lasts a few hours. That's why you take one tablet with each levodopa dose — so it...
- Why do I have to take entacapone every time I take my levodopa? Can't I just take it once a day?
- That's actually a well-known and harmless side effect of entacapone — it can turn your urine an orange-brown color. It doesn't mean anything is wrong with your kidneys or liver. Th...
- My urine looks orange or brownish since I started entacapone. Should I be worried?
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
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UNII M28OL1HH48
Croscarmellose sodium is a plant-based substance derived from cellulose. It acts as a disintegrant, helping tablets and capsules break down quickly in the digestive system so the medicine can be absorbed.
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UNII 1K09F3G675
Ferric oxide red is an inorganic iron compound used as a colorant in medicines. It gives tablets, capsules, or other dosage forms a red or reddish tint for identification and appearance.
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UNII EX438O2MRT
Ferric oxide yellow is a naturally occurring iron compound used as a colorant in medications. It gives tablets, capsules, and other forms a yellow or golden hue for identification and appearance.
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UNII PDC6A3C0OX
Glycerin is a clear, thick liquid derived from plant oils or fats. It acts as a humectant to retain moisture, a sweetener, and a solvent in medications.
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UNII Z82Y2C65EA
Hydrogenated cottonseed oil is a solid fat made by adding hydrogen to cottonseed oil. It's used in medicines as a binder and lubricant to help hold ingredients together and make tablets easier to compress and release.
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UNII 3NXW29V3WO
Hypromellose is a plant-based thickener made from cellulose. It's used in medicines as a binder to hold ingredients together, a coating for tablets, and a thickener for liquids.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII 3OWL53L36A
A natural sugar alcohol derived from seaweed or synthesized in the lab. It's used as a filler to add bulk, a sweetener in sugar-free formulas, and a disintegrant to help tablets break apart in the stomach.
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UNII OP1R32D61U
Microcrystalline cellulose is a purified form of cellulose, a natural fiber from plant sources. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and give the medicine its shape and size.
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UNII 6OZP39ZG8H
Polysorbate 80 is a synthetic emulsifier derived from sorbitol and oleic acid. It helps mix oil and water-based ingredients together in medications and improves how the product disperses in the body.
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UNII ETJ7Z6XBU4
Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
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UNII C151H8M554
A natural sugar derived from sugar cane or sugar beets. It's used as a sweetener, filler, and binder to improve taste, add bulk, and help hold tablet or capsule ingredients together.
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UNII 15FIX9V2JP
Titanium dioxide is a bright white mineral powder commonly used as a colorant and opacifying agent. It makes pills and tablets white or lighter in color and helps make coatings non-transparent.
13 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per each | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · Q2 2026 | $0.5524 | $55.24 / 100 tablets |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Entacapone 200 mg 00527-1830-37 | Lannett | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 00781-5578-01 | Sandoz | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 00904-6822-07 | Major | 1 tablet | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 27241-0049-10 | Ajanta | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 33342-0260-11 | Macleods | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 50268-0295-15 | AvPAK | 1 tablet | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 60687-0188-21 | American | 1 tablet | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 62332-0478-31 | Alembic | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 65862-0654-01 | Aurobindo | 100 tablets | $0.335 | AB | Availability likely | — |
| Entacapone 200 mg 47335-0007-88 | Sun | 100 tablets | $0.411 | AB | FDA listed | — |
| Entacapone 200 mg 00615-8298-39 | NCS | 30 tablets | — | AB | FDA listed | — |
| Entacapone 200 mgthis 46708-0478-31 | Alembic | 100 tablets | — | AB | FDA listed | — |
| Entacapone 200 mg 64980-0722-01 | Rising | 100 tablets | — | AB | FDA listed | — |
| Entacapone 200 mg 71610-0247-83 | Aphena | 3600 tablets | — | AB | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
Where does this data come from?
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 46708-0478-31 You're viewing this | 100 TABLET, FILM COATED in 1 BOTTLE (46708-478-31) | 2022-01-06 | Active |
| 46708-0478-91 | 1000 TABLET, FILM COATED in 1 BOTTLE (46708-478-91) | 2022-01-06 | Active |
You're viewing the smallest of 2 pack sizes for this product.
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What quantity is in NDC 46708-0478-31?
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🧭 About this NDC listing & data coverage
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| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | — Not published for this NDC Most self-administered / retail products have no J-code — that is normal. |
| Medicaid utilization (CMS SDUD) | — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold. |
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📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS Entacapone tablets are indicated as an adjunct to levodopa and carbidopa to treat end-of-dose “wearing-off” in patients with Parkinson’s disease (see CLINICAL PHARMACOLOGY, Clinical Studies). Entacapone tablets effectiveness has not been systematically evaluated in patients with Parkinson’s disease who do not experience end-of-dose “wearing-off”.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION The recommended dose of entacapone is one 200 mg tablet administered concomitantly with each levodopa and carbidopa dose to a maximum of 8 times daily (200 mg x 8 = 1,600 mg per day). Clinical experience with daily doses above 1,600 mg is limited. Entacapone tablets should always be administered in association with levodopa and carbidopa.
Entacapone has no antiparkinsonian effect of its own. In clinical studies, the majority of patients required a decrease in daily levodopa dose if their daily dose of levodopa had been greater than or equal to 800 mg or if patients had moderate or severe dyskinesia before beginning treatment. To optimize an individual patient’s response, reductions in daily levodopa dose or extending the interval between doses may be necessary.
In clinical studies, the average reduction in daily levodopa dose was about 25% in those patients requiring a levodopa dose reduction. (More than 58% of patients with levodopa doses above 800 mg daily required such a reduction.) Entacapone tablets can be combined with both the immediate and sustained-release formulations of levodopa and carbidopa. Entacapone tablets may be taken with or without food (see CLINICAL PHARMACOLOGY).
Patients With Impaired Hepatic Function : Patients with hepatic impairment should be treated with caution. The AUC and C max of entacapone approximately doubled in patients with documented liver disease, compared to controls. However, these studies were conducted with single-dose entacapone without levodopa and dopa decarboxylase inhibitor coadministration, and therefore the effects of liver disease on the kinetics of chronically administered entacapone have not been evaluated (see CLINICAL PHARMACOLOGY, Pharmacokinetics of Entacapone).
Withdrawing Patients from Entacapone Tablets : Rapid withdrawal or abrupt reduction in the entacapone tablets dose could lead to emergence of signs and symptoms of Parkinson’s disease (see CLINICAL PHARMACOLOGY, Clinical Studies), and may lead to hyperpyrexia and confusion, a symptom complex resembling NMS (see PRECAUTIONS, Other Events Reported With DopaminergicTherapy). This syndrome should be considered in the differential diagnosis for any patient who develops a high fever or severe rigidity. If a decision is made to discontinue treatment with entacapone tablets, patients should be monitored closely and other dopaminergic treatments should be adjusted as needed.
Although tapering entacapone has not been systematically evaluated, it seems prudent to withdraw patients slowly if the decision to discontinue treatment is made.
⛔ Contraindications ▾
CONTRAINDICATIONS Entacapone tablets are contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients.
⚠️ Warnings ▾
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 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 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, 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, 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.
Patients who have already experienced somnolence and/or an episode of sudden sleep onset should not participate in these activities during treatment with entacapone. Before initiating treatment with entacapone, 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 should ordinarily be discontinued (see DOSAGE AND ADMINISTRATION for guidance on discontinuing entacapone).
If the decision is made to continue entacapone, patients should be advised not to drive and to avoid other potentially dangerou…
🤒 Adverse Reactions ▾
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 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 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 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 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 25 15 Hyperkinesia 10 5 Hypokinesia 9 8 Dizziness 8 6 SPECIAL SENSES, OTHER DISORDERS Taste perversion 1 0 PSYCHIATRIC DISORDERS Anxiety 2 1 Somnolence 2 0 Agitation 1 0 GASTROINTESTINAL SYSTEM DISORDERS Nausea 14 8 Diarrhea 10 4 Abdominal pain 8 4 Constipation 6 4 Vomiting 4 1 Mouth dry 3 0 Dyspepsia 2 1 Flatulence 2 0 Gastritis 1 0 Gastrointestinal disorders 1 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 4 2 Fatigue 6 4 Asthenia 2 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 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 exposure. Hepatitis with mainly cholestatic features has been reported.
🔄 Drug Interactions ▾
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. 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 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.
🤰 Pregnancy ▾
Pregnancy In embryofetal development studies, entacapone was administered to pregnant animals throughout organogenesis at doses of up to 1,000 mg/kg/day in rats and 300 mg/kg/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, late and total resorptions, and decreased fetal weights were observed in the litters of rabbits treated with maternally toxic doses of 100 mg/kg/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/kg/day (plasma AUCs 7 times those in humans receiving the MRDD) or greater, in the absence of maternal toxicity.
Administration of up to 700 mg/kg/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 in pregnant women. Therefore, entacapone should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
🧒 Pediatric Use ▾
Pediatric Use Safety and effectiveness in pediatric patients have not been established.
🆘 Overdosage ▾
OVERDOSAGE The postmarketing data include several cases of overdose. The highest reported dose of entacapone was at least 40,000 mg. The acute symptoms and signs commonly seen in these cases included somnolence and decreased activity, states related to depressed level of consciousness (e.g., coma, confusion and disorientation) and discolorations of skin, tongue, and urine, as well as restlessness, agitation, and aggression.
COMT inhibition by entacapone treatment is dose-dependent. A massive overdose of entacapone may theoretically produce a 100% inhibition of the COMT enzyme in humans, thereby preventing the metabolism of endogenous and exogenous catechols. The highest daily dose given to humans was 2,400 mg, administered in one study as 400 mg six times daily with levodopa and carbidopa for 14 days in 15 Parkinson’s disease patients, and in another study as 800 mg three times daily for 7 days in 8 healthy volunteers.
At this daily dose, the peak plasma concentrations of entacapone averaged 2 mcg per mL (at 45 minutes, compared to 1 mcg per mL and 1.2 mcg per mL with 200 mg entacapone at 45 minutes). Abdominal pain and loose stools were the most commonly observed adverse events during this study. Daily doses as high as 2,000 mg entacapone have been administered as 200 mg 10 times daily with levodopa and carbidopa or levodopa and benserazide for at least 1 year in 10 patients, for at least 2 years in 8 patients and for at least 3 years in 7 patients.
Overall, however, clinical experience with daily doses above 1,600 mg is limited. The range of lethal plasma concentrations of entacapone based on animal data was 80 mcg per mL to 130 mcg per mL in mice. Respiratory difficulties, ataxia, hypoactivity, and convulsions were observed in mice after high oral (gavage) doses.
Management of Overdose Management of entacapone overdose is symptomatic; there is no known antidote to entacapone. Hospitalization is advised, and general supportive care is indicated. There is no experience with hemodialysis or hemoperfusion, but these procedures are unlikely to be of benefit, because entacapone is highly bound to plasma proteins.
An immediate gastric lavage and repeated doses of charcoal over time may hasten the elimination of entacapone by decreasing its absorption and reabsorption from the gastrointestinal (GI) tract. The adequacy of the respiratory and circulatory systems should be carefully monitored and appropriate supportive measures employed. The possibility of drug interactions, especially with catechol-structured drugs, should be borne in mind.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Mechanism of Action Entacapone is a selective and reversible inhibitor of COMT. In mammals, COMT is distributed throughout various organs with the highest activities in the liver and kidney. COMT also occurs in the heart, lung, smooth and skeletal muscles, intestinal tract, reproductive organs, various glands, adipose tissue, skin, blood cells, and neuronal tissues, especially in glial cells.
COMT catalyzes the transfer of the methyl group of S-adenosyl-L-methionine to the phenolic group of substrates that contain a catechol structure. Physiological substrates of COMT include dopa, catecholamines (dopamine, norepinephrine, and epinephrine) and their hydroxylated metabolites. The function of COMT is the elimination of biologically active catechols and some other hydroxylated metabolites.
In the presence of a decarboxylase inhibitor, COMT becomes the major metabolizing enzyme for levodopa, catalyzing the metabolism to 3-methoxy-4-hydroxy-L phenylalanine (3-OMD) in the brain and periphery. The mechanism of action of entacapone is believed to be through its ability to inhibit COMT and alter the plasma pharmacokinetics of levodopa. When entacapone is given in conjunction with levodopa and an aromatic amino acid decarboxylase inhibitor, such as carbidopa, plasma levels of levodopa are greater and more sustained than after administration of levodopa and an aromatic amino acid decarboxylase inhibitor alone.
It is believed that at a given frequency of levodopa administration, these more sustained plasma levels of levodopa result in more constant dopaminergic stimulation in the brain, leading to greater effects on the signs and symptoms of Parkinson’s disease. The higher levodopa levels also lead to increased levodopa adverse effects, sometimes requiring a decrease in the dose of levodopa. In animals, while entacapone enters the central nervous system (CNS) to a minimal extent, it has been shown to inhibit central COMT activity.
In humans, entacapone inhibits the COMT enzyme in peripheral tissues. The effects of entacapone on central COMT activity in humans have not been studied. Pharmacodynamics COMT Activity in Erythrocytes: Studies in healthy volunteers have shown that entacapone reversibly inhibits human erythrocyte COMT activity after oral administration.
There was a linear correlation between entacapone dose and erythrocyte COMT inhibition, the maximum inhibition being 82% following an 800 mg single dose. With a 200 mg single dose of entacapone, maximum inhibition of erythrocyte COMT activity is on average 65% with a return to baseline level within 8 hours. Effect on the Pharmacokinetics of Levodopa and its Metabolites When 200 mg entacapone is administered together with levodopa and carbidopa, it increases the area under the curve (AUC) of levodopa by approximately 35% and the elimination half-life of levodopa is prolonged from 1.3 hours to 2.4 hours.
In general, the average peak levodopa plasma concentration and the time of its occurrence (T max of 1 hour) are unaffected. The onset of effect occurs after the first administration and is maintained during long-term treatment. Studies in Parkinson’s disease patients suggest that the maximal effect occurs with 200 mg entacapone.
Plasma levels of 3-OMD are markedly and dose-dependently decreased by entacapone when given with levodopa and carbidopa. Pharmacokinetics of Entacapone Entacapone pharmacokinetics are linear over the dose range of 5 mg to 800 mg, and are independent of levodopa and carbidopa coadministration. The elimination of entacapone is biphasic, with an elimination half-life of 0.4 hour to 0.7 hour based on the β-phase and 2.4 hours based on the γ-phase.
The γ-phase accounts for approximately 10% of the total AUC. The total body clearance after intravenous administration is 850 mL per min. After a single 200 mg dose of entacapone, the C max is approximately 1.2 mcg per mL.
Absorption : Entacapone is rapidly absorbed, with a T max of approximately…
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Entacapone Tablets USP, 200 mg are brownish-orange colored, oval-shaped unscored film coated tablets debossed with “L 633” on one side and plain on the other side. Tablets are provided in HDPE containers as follows: NDC 46708-478-31 bottle of 100 tablets NDC 46708-478-91 bottle of 1,000 tablets Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature.] Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Manufactured by: Alembic Pharmaceuticals Limited (Formulation Division), Village Panelav, P. O. Tajpura, Near Baska, Taluka-Halol, Panchmahal 389350, Gujarat, India.
Revised: 09/2021
📋 Description ▾
DESCRIPTION Entacapone is available as tablets containing 200 mg entacapone, USP. Entacapone is an inhibitor of catechol-O-methyltransferase (COMT), used in the treatment of Parkinson’s disease as an adjunct to levodopa and carbidopa therapy. It is a nitrocatechol-structured compound with a relative molecular mass of 305.29.
The chemical name of entacapone is (E)-2-cyano3-(3,4-dihydroxy-5-nitrophenyl)-N,N-diethyl-2-propenamide. Its empirical formula is C 14 H 15 N 3 O 5 and its structural formula is: The inactive ingredients of the entacapone tablets, USP are microcrystalline cellulose, mannitol, croscarmellose sodium, colloidal silicon dioxide, magnesium stearate, hydrogenated vegetable oil, hypromellose, glycerin, titanium dioxide, iron oxide yellow, sucrose, polysorbate 80 and iron oxide red. FDA approved dissolution testing specifications differ from USP. structure
💬 Information for Patients ▾
Information for Patients Instruct patients to take entacapone only as prescribed. Inform patients that hallucinations and/or other psychotic-like behavior can occur. Advise patients that they may develop postural (orthostatic) hypotension with or without symptoms such as dizziness, nausea, syncope, and sweating.
Hypotension may occur more frequently during initial therapy. Accordingly, patients should be cautioned against rising rapidly after sitting or lying down, especially if they have been doing so for prolonged periods, and especially at the initiation of treatment with entacapone. Advise patients that they should neither drive a car nor operate other complex machinery until they have gained sufficient experience on entacapone to gauge whether or not it affects their mental and/or motor performance adversely.
Warn patients about the possibility of sudden onset of sleep during daily activities, in some cases without awareness or warning signs, when they are taking dopaminergic agents, including entacapone. Because of the possible additive sedative effects, caution should be used when patients are taking other CNS depressants in combination with entacapone. Inform patients that nausea may occur, especially at the initiation of treatment with entacapone.
Inform patients that diarrhea may occur with entacapone and it may have a delayed onset. Sometimes prolonged diarrhea may be caused by colitis (inflammation of the large intestine). Patients with diarrhea should drink fluids to maintain adequate hydration and monitor for weight loss.
If diarrhea associated with entacapone is prolonged, discontinuing the drug is expected to lead to resolution, if diarrhea continues after stopping entacapone, further diagnostic investigations may be needed. Advise patients about the possibility of an increase in dyskinesia. Tell patients that treatment with entacapone may cause a change in the color of their urine (a brownish orange discoloration) that is not clinically relevant.
In controlled studies, 10% of patients treated with entacapone reported urine discoloration compared to 0% of placebo patients. Although entacapone has not been shown to be teratogenic in animals, it is always given in conjunction with levodopa and carbidopa, which is known to cause visceral and skeletal malformations in rabbits. Accordingly, patients should be advised to notify their physicians if they become pregnant or intend to become pregnant during therapy (see PRECAUTIONS, Pregnancy).
Entacapone is excreted into maternal milk in rats. Because of the possibility that entacapone may be excreted into human maternal milk, advise patients to notify their physicians if they intend to breastfeed or are breastfeeding an infant. Tell patients and family members to notify their healthcare practitioner if they notice that the patient develops unusual urges or behaviors.