Drugs for Parkinson's disease.

Levodopa combined with carbidopa is still the most effective treatment for symptoms of Parkinson's disease. Dopamine agonists, the next most effective class of drugs, can be used alone before the introduction of levodopa or as an adjunct to levodopa.Addition of a peripherally-acting COMT inhibitor or an MAO-B inhibitor to levodopa can reduce motor fluctuations in patients with advanced disease.Amantadine may have mild symptomatic benefit and can decrease levodopa-induced dyskinesias.Anticholinergics are rarely used because of their adverse effects, but can be a useful addition to levodopa for control of tremor and drooling.Subcutaneous apomorphine should be available for rescue use in patients with 'off' episodes. Deep brain stimulation is an option for patients with levodopa-induced motor complications and relatively intact cognition.