Entacapone: uses, dosing, side effects & brands
Entacapone is a catechol-o-methyltransferase inhibitor sold in the U.S. under one brand, for parkinson disease. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Catechol-O-Methyltransferase Inhibitor
- Treats
- Parkinson Disease
- Available as
- Tablet
- Sold as
- Comtan
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- What the pharmacy pays
- about $11 for a 30-count supply — not your price
How entacapone is dosed
From the FDA label for Comtan (application NDA020796). Other entacapone products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended dose of Entacapone Tablets 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…
Entacapone side effects
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:…
Who shouldn’t take entacapone
Entacapone Tablets are contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients.
Entacapone 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% [CI90 11% to 26%], and the international normalized ratio (INR) values increased on average by 13% [CI90 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.
Every entacapone product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Comtan.
What entacapone pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| L7 | 200 mg | brown | oval | — |
| S51 | 200 mg | orange | oval | — |
Combination products containing entacapone
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
How long entacapone keeps
No entacapone label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Does entacapone expire? The in-use limits and storage rules from its labelsWhat people report to the FDA about entacapone
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 5,949 reports naming entacapone, and the FDA flagged 74% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- fall658 reports
- hallucination626 reports
- dyskinesia598 reports
- parkinson^s disease402 reports
- gait disturbance335 reports
- confusional state332 reports
- tremor324 reports
- on and off phenomenon315 reports
Read these as a signal, not a rate. A report does not mean entacapone caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
Related calculators
Frequently asked questions
What is entacapone?
Entacapone is available as tablets containing 200 mg entacapone. 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.
What kind of drug is entacapone?
The FDA classifies entacapone as a catechol-o-methyltransferase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take entacapone with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run entacapone against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does entacapone come in?
Across the brands we track, entacapone is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic entacapone?
We do not currently list a generic-labelled entacapone product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Entacapone: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/entacapone
- MLA
- “Entacapone: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/entacapone.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for entacapone on DailyMed (NIH) ↗.