Bromocriptine associated with a peripheral dopamine blocking agent in treatment of Parkinson's disease.

A peripheral dopaminergic blocking agent, domperidone (60 mg daily), or placebo was given, double-blind, to 17 parkinsonian patients who also received increasing doses of bromocriptine. Combined treatment with domperidone reduced total disability by 76% in 8 patients receiving a mean dose of 148 mg of bromocriptine daily. There was no vomiting and involuntary movements and psychic disturbances were similar to those in patients on levodopa and a peripheral decarboxylase inhibitor. In 9 patients taking placebo instead of domperidone, the average daily dose of bromocriptine could not be raised beyond 92 mg. The mean total disability score in this group was reduced by only 48%. Thus, peripheral blockade of dopamine receptors is a promising means of limiting the adverse side-effects of the treatment of parkinsonism with central dopaminergic receptor stimulating agents such as bromocriptine.