Pharmacologic Management of Parkinson Disease: Choice of Initial Therapy in Early Disease

The most efficacious symptomatic agent for Parkinson's disease is levodopa; however, the development of motor complications with long-term therapy is concerning. In the modern day treatment of Parkinson's disease, non-levodopa agents (eg, dopamine agonists, monoamine oxidase type B inhibitors) should be considered as appropriate initial treatments. In early Parkinson's disease, dopamine agonists provide effective symptomatic therapy, reduce the risk for motor complications, and delay the need to initiate levodopa. However, the dopamine agonists are associated with impulse control disorders and behaviors that are concerning. Monoamine oxidase type B inhibitors are also effective as monotherapy for early stage Parkinson's disease. Clinical data demonstrate that early initiation of rasagiline (in the absence of functional impairment) is associated with improved outcomes as opposed to delayed initiation. Selegiline can delay the need for levodopa, albeit its clinical effectiveness as monotherapy is equivocal. When selecting initial therapy for early Parkinson's disease, clinicians must consider both short-term and long-term benefits and risks.