Sustained bromocriptine therapy in 50 previously untreated patients with Parkinson's disease.

The progress of 50 previously untreated patients with idiopathic Parkinson's disease taking maximum tolerated doses of bromocriptine is described. Twenty-eight showed sustained benefit, defined as a 25% improvement in disability scores for at least 1 year, and in five this improvement persisted for longer than 5 years. However, there was a tendency for deterioration to occur after about 2 years of bromocriptine. Fewer of the late complications associated with levodopa therapy were seen in those taking bromocriptine, and drug-induced dyskinesia was seen in only one patient. Fourteen early bromocriptine failures subsequently responded well to levodopa, but the addition of levodopa to patients showing late deterioration on long-term bromocriptine was unsuccessful. These results indicate that the total duration of effective drug treatment for Parkinson's disease cannot be extended by giving bromocriptine before commencing levodopa.