The early treatment of Parkinson's disease: levodopa, dopamine agonists or both

Much has been written about the pharmacologic management of Parkinson's disease (PD) because of an expanding arsenal of antiparkinson drugs and our quest to alter the natural history of disease. Choice of initial therapy may prove fundamental to a treatment strategy that maximizes symptomatic control while minimizing the chances for long-term complications such as motor fluctuations and dyskinesias. Dopamine agonists (DA) have assumed a primary role in the early therapy of PD because of their antiparkinson effectiveness and low propensity to induce fluctuations and dyskinesias. Four available DA in the United States and an array of recent studies supporting their utility in early PD have shaped current PD management. Moreover, DA have neuroprotective properties in vivo. Nevertheless, levodopa remains the most effective drug for symptomatic control in PD. There is conflicting evidence regarding the putative neurotoxicity of levodopa and the mechanisms for levodopa-related motor fluctuations are not entirely known. Clinicians must therefore weigh the available evidence as they initiate therapy in PD. Clearly, both DA and levodopa will remain essential components of the early management of PD.