Agonist or levodopa for Parkinson disease?

Initial dopaminergic therapy for Parkinson disease (PD) with an agonist, rather than levodopa, is associated with a lower risk of mild dyskinesias and motor fluctuations in the first 5 years of treatment.^1,2 This short-term advantage of agonists is offset by providing less symptom relief and a higher incidence of adverse effects. The American Academy of Neurology practice parameter on initiating treatment for PD concluded that therapy needs to be individualized and that either levodopa or an agonist is acceptable.³ Despite this, “levodopa phobia”⁴ abounds: many are under the impression that initial treatment of PD should be an agonist and that it is advantageous to delay levodopa. Similarly, patients are often misinformed that levodopa “stops working” after 5 years and inappropriately view the initiation of levodopa as starting down a slippery slope.

Is levodopa phobia justified? Until recently, little was known about how the initial choice of a dopaminergic agent influences the long-term manifestations of PD. If starting with an agonist reduced the incidence of …