Dopamine agonists in the treatment of Parkinson's disease.

Clinical responses to bromocriptine and three new ergoline derivatives, CM 29-712, CQ 32-084, and CU 32-085, in the treatment of Parkinson's disease were studied in new, non-levodopa-treated parkinsonian patients. All compounds elicited a significant but mostly only mild or moderate antiparkinsonian efficacy which seems to be less than that of levodopa. The therapeutic profile of the dopaminergic agonists studied was similar, and the improvement in tremor was considerably better than that in rigidity and hypokinesia. All of the compounds elicited clinical side effects typical of dopaminergic agonists but differed both quantitatively and qualitatively in certain respects. Fewer side effects, especially reduced blood pressure or the occurrence of postural hypotension, developed during treatment with CU 32-085. It is evident that more effective, specific, and tolerable dopaminergic agonists are needed before they can be considered a primary treatment of Parkinson's disease. At present, the main indications for dopaminergic agonists seem to be a deteriorating response to levodopa and daily fluctuations in performance.