COMT inhibitor

A COMT inhibitor is a drug that inhibits the action of catechol-O-methyl transferase. This enzyme is involved in degrading neurotransmitters. COMT inhibitors are used in the treatment of Parkinson's disease.

Pharmaceutical examples include entacapone, tolcapone, and nitecapone. Entacapone is only peripherally active, whereas both tolcapone and nitecapone are active in both the periphery and central nervous system. Tolcapone and nitecapone are known to be hepatotoxic, whereas entacapone is not.