Nationwide multicenter prospective study on the long-term effects of bromocriptine for Parkinson's disease. Final report of a ten-year follow-up.

A 10-year nationwide multicenter prospective study on the long-term efficacy of bromocriptine for Parkinson's disease is reported. Six patients remained on bromocriptine monotherapy for 10 years, while 22 patients achieved good disease control with bromocriptine plus levodopa (added during the course of the study). In the 6 patients on bromocriptine alone, the disease remained in Hoehn and Yahr stage I or II for 10 years. In the other 22 patients on bromocriptine plus levodopa therapy, disease progression was very slow for 7-8 years. None of the 6 patients remaining on bromocriptine monotherapy experienced adverse reactions like the wearing-off phenomenon, dyskinesia, or the on-off phenomenon. Among the 22 patients who started levodopa therapy during the course of the study, these adverse reactions to levodopa were infrequent (10, 3, and 3 patients, respectively). Thus, early introduction and long continuation of bromocriptine therapy with restricted concomitant use of levodopa may have led to very slow disease progression and the suppression of adverse reactions. Although the patients who could be maintained long-term on bromocriptine monotherapy might represent a population who have very slowly progressive disease, their adequate disease control and the low incidence of adverse reactions in the patients who later started concomitant levodopa suggest that the unwanted effects of levodopa may be reduced by early and sustained treatment with bromocriptine. Introduction of bromocriptine monotherapy at an early stage of Parkinson's disease or with restricted use of additional levodopa therapy to bromocriptine when necessary may be a useful strategy for achieving adequate and sustained disease control.