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

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.

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 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.

View the Comparison Table: Drugs for Parkinson's Disease

A patch formulation of the non-ergot dopamine agonist rotigotine (Neupro – UCB) has returned to the US market after a 4-year absence. Originally approved by the FDA in 2007 for treatment of early Parkinson’s disease,1 it was withdrawn in 2008 because of crystallization of the drug in the patch, which could have led to under-dosing. The new patch has somewhat broader indications than the old one; it is approved for use in any stage of Parkinson’s disease (PD) and also for moderate-to-severe restless legs syndrome (RLS).

1. Transdermal rotigotine (Neupro) for Parkinson’s disease. Med Lett Drugs Ther 2007; 49:69.

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Gabapentin enacarbil (Horizant – GlaxoSmithKline), a new extended-release (ER) tablet formulation of gabapentin, has been approved by the FDA for treatment of moderate-to-severe restless legs syndrome (RLS). The immediate-release (IR) formulation of gabapentin (Neurontin,and others), which is approved for treatment of epilepsy and postherpetic neuralgia, has been used for many years to treat RLS. Another ER tablet formulation of gabapentin (Gralise) has been approved by the FDA for treatment of postherpetic neuralgia.

Parkinson’s disease (PD) is caused primarily by progressive degeneration of dopamine-containing neurons in the substantia nigra. Dopamine itself cannot be used to treat PD because it does not cross the blood-brain barrier.

Rotigotine (Neupro - Schwarz Pharma), a nonergot dopamine agonist in a transdermal patch formulation, was recently approved by the FDA for treatment of early Parkinson's disease (PD).

Ropinirole (Requip - GlaxoSmithKline), a dopamine agonist already available for treatment of Parkinson's disease, is now the first drug approved by the FDA for treatment of moderate to severe restless legs syndrome (RLS).

Recent articles in the press have trumpeted a new era in the management of Parkinson's disease: dopamine agonists have now replaced levodopa for initial treatment.