Optimizing long-term therapy for Parkinson disease: levodopa, dopamine agonists, and treatment-associated dyskinesia

The treatment of Parkinson disease (PD) involves pharmacological treatment, often with levodopa or dopamine agonists, to restore the dopaminergic deficit associated with parkinsonian symptoms. Either agent provides symptom relief that becomes less effective in the course of PD, and switching or combining these agents or adding other therapies becomes necessary for symptom control. In an effort to delay the development of motor complications, dopamine agonists are often used in the initial treatment of PD. However, control of PD symptoms is superior with levodopa. Moreover, dopamine agonists are less well tolerated overall and are associated with a number of rare but serious adverse effects. In the long-term management of PD, treatment-associated dyskinesia often becomes sufficiently troublesome as to compromise the effective dosing of antiparkinsonian medication. More effective strategies for managing dyskinesia are needed.