Tolcapone
Tolcapone is an antiparkinsonian medication used as an adjunct to levodopa therapy in patients with Parkinson's disease. It works by inhibiting the enzyme catechol-O-methyltransferase (COMT), which breaks down levodopa in the body, thereby prolonging its effects and reducing motor fluctuations. This medication is typically prescribed when patients do not respond adequately to standard levodopa/carbidopa or levodopa/benserazide combinations.
Tolcapone is a COMT inhibitor used alongside levodopa in Parkinson's disease to reduce motor fluctuations by preventing levodopa breakdown.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- N04BX01
- RxNorm
- 72937
- Generic
- Tolcapone
- Class
- atc-n04
- Brands
- Tasmar
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Adjunctive treatment to levodopa/carbidopa or levodopa/benserazide in Parkinson's disease patients experiencing end-of-dose motor fluctuations who do not respond adequately to other therapies.
Tolcapone selectively and reversibly inhibits catechol-O-methyltransferase (COMT), an enzyme that metabolizes levodopa in the peripheral tissues, thereby increasing levodopa availability to cross the blood-brain barrier and enhancing its therapeutic effect.
Due to risk of severe hepatotoxicity, tolcapone should be reserved for patients who fail other therapies and requires regular liver function monitoring. Discontinue if signs of liver injury appear. May cause or worsen dyskinesia and requires careful dose adjustment of levodopa.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy