Bromocriptine: long-term low-dose therapy in Parkinson's disease.

Low-dose bromocriptine therapy (average dose 14.5 mg/day at 2 years) produced significant improvement in 25 of 39 parkinsonian patients. Bradykinesia was less in de novo subjects; tremor and rigidity improved most in the levodopa subjects. Five of six patients improved after a low-dose bromocriptine drug "holiday." After the addition of bromocriptine any reductions in levodopa dosage were small, with repeated cuts made gradually over months preventing the deterioration commonly seen with larger sudden reductions in levodopa dosage. Five patients withdrew because of intolerable adverse effects, two because of worsening response. Adverse effects were mild and generally dose dependent, and in some patients they disappeared without reduction in continuing bromocriptine therapy. Eighty percent of those who tolerated bromocriptine maintained response over 2 years. Bromocriptine did not induce dyskinesia, the wearing-off response, or the on-off phenomenon in de novo subjects and was used as a first choice drug in these parkinsonian patients. Best results were obtained from a combination of bromocriptine and levodopa.