Levodopa combined with carbidopa (Sinemet, and others) is the most widely used treatment for patients with Parkinson's disease, but after 2 to 5 years most patients develop troublesome complications (Treatment Guidelines from The Medical Letter 2004; 2:41). The newest treatment for Parkinson's disease patients with end-of-dose "wearing-off" is Stalevo (Novartis), a combination of the catechol-O-methyltransferase (COMT) inhibitor entacapone (Comtan) with 3 different doses of levodopa/carbidopa. The rationale for Stalevo is that it permits some patients to take only one pill rather than...

Entacapone (Comtan), a catechol-O-methyltransferase (COMT) inhibitor, has been approved by the FDA for adjunctive use with levodopa/carbidopa in patients with Parkinson's disease who have end-of-dose "wearing off"symptoms.

The FDA has approved opicapone (Ongentys – Neurocrine), a peripherally-acting reversible catechol-O-methyltransferase (COMT) inhibitor, for oral use as an adjunct to carbidopa/levodopa in adults with Parkinson’s disease (PD) who experience "off" episodes. It is the third COMT inhibitor to be approved for this indication; tolcapone (Tasmar, and generics) and entacapone (Comtan, and generics) were approved earlier. Opicapone has been available in Europe since 2016.

The FDA has approved an extended-release tablet formulation of amantadine (Osmolex ER – Vertical/Osmotica) for once-daily treatment of Parkinson's disease (PD) and drug-induced extrapyramidal symptoms (EPS) in adults. An extended-release capsule formulation of amantadine (Gocovri) was approved in 2017 for treatment of levodopa-induced dyskinesia in patients with PD.

The FDA has approved istradefylline (Nourianz — Kyowa Kirin), an oral adenosine A_2A receptor antagonist, for use as an adjunct to carbidopa/levodopa in adults with Parkinson's disease (PD) who experience "off" episodes. Istradefylline is the first adenosine A_2A receptor antagonist to be approved in the US; it has been available in Japan since 2013.

Rasagiline (Azilect - Teva), a monoamine oxidase-type B (MAO-B) inhibitor, was recently approved by the FDA for once-daily oral treatment of Parkinson's disease (PD). It can be taken alone for treatment of early disease or with levodopa/carbidopa (Sinemet, and others) for advanced disease. Selegiline (Eldepryl, and others), the first MAO-B inhibitor marketed in the US, has been available since 1988; a new lower-dose disintegrating tablet (Zelapar) was recently approved.

The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems. No disease-modifying drugs are available for treatment of PD.

View the Comparison Table: Drugs for Parkinson's Disease