Long-term treatment with high-dosage bromocriptine in advanced Parkinson's disease.

Long-term follow-up indicated that levodopa as a replacement therapy merely improves the parkinsonian symptoms, and does so for only a limited number of years. The reason for this tachyphylaxis or declining efficacy in levodopa therapy and the increasing number and intensity of various distressing difficulties in the management of Parkinson's disease, such as dyskinesias and on-off phenomena, is the main subject of many recent studies. It is still widely accepted that levodopa provides the best therapeutic tool for Parkinson's disease. Bromocriptine, an ergot derivative, is the main clinically used dopamine agonist, and it has been established as a valuable adjunct in the treatment of Parkinson's disease. Bromocriptine is most useful in patients with a declining efficacy of levodopa treatment, in patients with diurnal oscillations in motor performance, especially in patients with wearing-off phenomena, and in patients with onset and end-of-dose dyskinesias. The question of bromocriptine dosage, required to obtain an optimal benefit and a decreased rate of late adverse reactions, is quite controversial. The trend has been to lower daily dosage of bromocriptine, i.e., low doses suffice in patients with mild, early disease. Higher doses of bromocriptine seem to be required in patients with severe parkinsonian deficits. In this retrospective study of 8 years experience with high dosage of bromocriptine in levodopa response-losing parkinsonian patients, the adjunction of bromocriptine had a clear-cut but short-lasting beneficial effect on the disability scores.(ABSTRACT TRUNCATED AT 250 WORDS)