COMT Inhibitors

Catechol-o-methyl transferase (COMT) inhibitors block levodopa metabolism, prolonging levodopa effects. COMT inhibitors thus have no effect on their own and are always used in conjunction with levodopa. COMT inhibitors are used primarily to treat motor fluctuations and reduce OFF time. Possible side effects include diarrhea and discolored urine. Because COMT inhibitors increase and prolong the effects of levodopa, the side effects of levodopa may also be enhanced, including dyskinesia.

Generic Name
Trade Name
Patient Assistance
Entacapone Comtan® Prescribing Information
Tolcapone Tasmar® Rare but possible serious side effects on the liver, so typically only used if other Parkinson’s medications have failed.
Carbidopa/Levodopa/Entacapone Stalevo® An alternative to just carbidopa/levodopa that is combined with entacapone to help with motor fluctuations. Product Website Novartis Patient Assistance
Opicapone Ongentys® Approved 2020. Once-daily dosing. Prescribing Information

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