[Role of dopaminergic agonists]

The usefulness of an initial treatment of Parkinson's disease with a dopamine agonist has now been studied for more than 20 years. The first clinical trials compared the long-term out come of patients receiving early bromocriptine or lisuride to those receiving initial L-dopa. These pilot data suggested that the early use of these agonists (combined early or supplemented later with low doses of L-dopa) reduced the risk of occurence of motor complications such as dyskinesia and/or fluctuations. These initial conclusions were however criticised because of methodological limitations in study design. The recent results from new large prospective randomized double-blind 5-year L-dopa-controlled trials using newer dopamine agonists (cabergoline and ropinirole) confirmed the findings of the previous pilot studies. Therefore, one now generally agrees that the early use of such agonists (to which low doses of L-dopa may be added as a second step if necessary to maintain an adequate control of parkinsonian symptoms) is useful to reduce the risk of occurence of motor complications. This result is achieved without a major increase in the risk of other dopaminergic adverse events (digestive, cardiovascular, psychiatric), specially in 'young' patients (before 70 years).