The FDA has approved Crexont (Amneal), an extended-release capsule formulation of carbidopa/levodopa, for treatment of Parkinson's disease (PD), postencephalitic parkinsonism, and parkinsonism associated with carbon monoxide or manganese intoxication. Crexont contains a combination of immediate-release carbidopa/levodopa granules and extended-release levodopa pellets. An extended-release carbidopa/levodopa oral capsule (Rytary) has been available from the same manufacturer for years; the patent for Rytary expires in 2025.

Vyalev (Abbvie), a solution for continuous subcutaneous infusion containing the prodrugs foscarbidopa and foslevodopa, has been approved by the FDA for treatment of motor fluctuations in adults with advanced Parkinson's disease (PD). Vyalev is the first subcutaneously administered product to become available in the US for treatment of PD symptoms. Duopa, a carbidopa/levodopa enteral suspension infused via a nasojejunal tube or percutaneous gastrostomy, was approved in for the same indication 2015.

View the Comparison Table: Drugs for Parkinson's Disease

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.

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 a sublingual fi lm formulation of the nonergot dopamine agonist apomorphine (Kynmobi – Sunovion) for acute, intermittent treatment of "off" episodes in patients with Parkinson's disease (PD). A subcutaneous formulation of apomorphine (Apokyn) has been available for years for the same indication in patients with advanced PD.