Opicapone, sold under the brand name Ongentys, is a medication which is administered together with levodopa in people with Parkinson's disease.

[3] The most common side effects are dyskinesia (difficulty controlling movement), constipation, increased blood creatine kinase, hypotension/syncope, and decreased weight.

[10][6][9] In the EU, opicapone is indicated as adjunctive therapy to preparations of levodopa/ DOPA decarboxylase inhibitors (DDCI) in adults with Parkinson's disease and end-of-dose motor fluctuations who cannot be stabilised on those combinations.

Other contraindications are a history of neuroleptic malignant syndrome (NMS) or non-traumatic rhabdomyolysis, and combination with monoamine oxidase inhibitors that are not used as antiparkinsonians, because of possible drug interactions.

Other common side effects (in 1 to 10% of patients) include dizziness, strange dreams, hallucinations, constipation, dry mouth, orthostatic hypotension (low blood pressure), and muscle spasms.

[11] Opicapone blocks the enzyme catechol-O-methyltransferase (COMT) effectively (>90% at therapeutic doses), selectively and reversibly, and only outside the central nervous system.

It dissociates slowly from COMT, resulting in a duration of action longer than 24 hours despite its short blood plasma half-life.

[11][13] As COMT and DOPA decarboxylase are the main enzymes for degrading levodopa, blocking the two effectively increases its concentrations in the bloodstream.

Opicapone itself and the sulfate are also transported by a number of other proteins, but given the low concentrations of the free substances in the blood plasma, this is very unlikely to give rise to drug interactions.

[4][8][9] In February 2017, its developer Bial sold exclusive marketing rights for the United States and Canada to Neurocrine Biosciences for an initial payment of US$30 million.

[6] The benefit was evaluated by measuring the change from baseline in total daily "off" time in opicapone- and placebo-receiving participants.

[17] The applicant for this medicinal product is Bial Portela & Companhia S.A.[17] Opicapone was approved for medical use in the European Union in February 2022.