Should treatment of Parkinson's disease be started with a dopamine agonist?

Which drugs to use when initiating pharmacotherapy in early Parkinson's disease (PD) is a complex treatment decision that depends on factors such as disease severity, functional disability, and psychosocial handicap, as well as individual aspects of age, employment status, cognitive impairment, and co-morbidity. Without clear proof of a drug's capacity to markedly alter or even stop progression of the disease, there is no pharmacologic strategy that can be currently viewed as universal first-line treatment. Dopamine (DA) replacement strategies offer greatest symptomatic relief and are needed whenever there is significant functional disability. All currently available oral DA agonists have been shown to be less effective and less well tolerated than levodopa. This has also been shown in recent double-blind controlled studies for the novel agonists such as ropinirole or cabergoline, although they appear equally effective in mild disease for the first 6-12 months of therapy. Taking into account the significant difference in cost between levodopa and DA agonists, there is at present no reason to universally start DA replacement therapy with a DA agonist in most patients. Dopamine agonists remain first-line treatment only for those at particular risk for developing levodopa-induced dyskinesias, i.e., young-onset PD patients.