Comparative efficacy of pergolide and bromocriptine in patients with advanced Parkinson's disease

Treatment with pergolide was compared with bromocriptine in 25 patients, all of whom were also receiving levodopa and in all of whom the response to levodopa had diminished. All 25 patients had "on-off" phenomena. At the time bromocriptine was added to levodopa, the mean age of the patients was 61.8 years, mean duration of disease was 9.0 years, and mean duration of levodopa treatment was 6.1 years. For the group as a whole, disability as determined in the "on" period decreased by 36%, from 28.7 to 18.5; and 11 patients improved at least one stage. Disability as determined in the "off" period decreased by 25%, from 59.5 to 44.4. The number of hours in which patients were "on" increased by 62%, from 7.1 to 11.5. All of these changes were significant (p less than or equal to 0.05). Bromocriptine had to be discontinued in nine patients (eight because of mental changes). In the remaining 16 patients, bromocriptine was eventually discontinued because of diminishing efficacy. Mean dose of bromocriptine was 50 mg (range, 10-100 mg), and mean duration of treatment was 23 months (range, 2-65 months). At the time of their treatment with pergolide, the patients were older, 65.5 years, had the disease longer, 12.7 years, and were more disabled. Nonetheless, for the group as a whole, disability score as determined in the "on" period decreased significantly by 40%, from 43.5 to 26.3, and 14 patients improved at least one stage. Disability as determined in the "off" period decreased significantly by 21%, from 69.0 to 54.8. The number of hours in which patients were "on" increased significantly by 224%, from 3.4 to 11.0 hr. The mean dose of pergolide was 2.1 mg (range, 0.1-10.0 mg), and the mean duration of treatment was 6.2 months (range, 0.5-20 months). Pergolide was discontinued in eight patients: three because of asymptomatic tachyarrhythmias of unknown clinical significance (detected only by Holter monitoring); two because of orthostatic hypotension; and two because of mental changes. Although pergolide appears to be more potent than bromocriptine because of its greater effect in a larger number of patients at a more advanced stage of their disease, both drugs are useful, and both enhance our ability to manage patients with PD.