Bromocriptine (CB-154) and the 8-alpha-ergoline
CU 32-085, two
dopamine receptor agonists, were administered at different times to two series of 22 patients with
Parkinson's disease, most of whom took
levodopa (plus
benserazide) at optimum dosage. The addition of
bromocriptine (mean daily dose 32 mg; after 6 months 40 mg) led to a 38.5% reduction of
levodopa, while
CU 32-085 (mean daily dose 15.2 mg; after 6 months 17.5 mg) permitted a 33.7% reduction in
levodopa. The mean dose in two patients on
CU 32-085 monotherapy was 55 mg/day. A total of 15 patients tolerated adequate doses of
bromocriptine (5-75 mg/day, mean
duration of treatment 7.5 months) and 15 patients long-term treatment up to 14 months with
CU 32-085 (dose range 1-60 mg/day; mean duration 8.8 months). Both groups showed a significant improvement of "total disability score' at 6 months by 56% and 67%, respectively, and after 6 months by 69% and 69.4%, respectively, with a significant decrease of all types of disability. All patients with fluctuations and "on-off' effects rapidly improved on both compounds.
Bromocriptine and
CU 32-085 were discontinued in seven patients each (32%) because of adverse effect including mental changes (for with
bromocriptine, two with
CU 32-085),
nausea and
vomiting (one and two, respectively),
hypotension (one each) and increased
tremor plus
vomiting (one with
CU 32-085). Although adverse effects were similar to those observed with
levodopa,
CU 32-085 in general showed less severe
dyskinesia and mental changes but more frequent
nausea than
bromocriptine and
levodopa. While the results of treatment with
bromocriptine and
CU 32-085 were comparable, the antitremor effect of the latter
drug developed more rapidly, even at low dosage. Both compounds were useful in the management of patients with advanced
Parkinson's disease,
CU 32-085 having a stronger effect on
tremor,
bradykinesia, fluctuations and "on-off' effects than
bromocriptine.