Treatment of human hyperprolactinaemia with a new dopamine agonist: CU 32085 (mesulergin)

CU 38085 (mesulergin) was given at doses ranging from 0.5 to 5 mg/day to 37 patients with pathological hyperprolactinaemia of varying aetiology. The effectiveness of this drug on the suppression of hyperprolactinaemia and on the recovery of gonadal functions was equivalent to that of bromocriptine previously given to a different group of 83 hyperprolactinaemic patients. Tumour shrinkage during treatment with CU 32085 was ascertained in two cases of macroprolactinoma. Histological examination after adenomectomy revealed extensive peri-vascular fibrosis in both cases. In most patients, the efficient doses of CU 32085 were 5-fold lower than those of bromocriptine. After acute oral administration in 10 previously untreated patients, 0.5 mg of CU 32085 had a more prolonged suppressive effect on Prl levels than 2.5 mg of bromocriptine (approximately 18 vs 12 h). According to this, 0.5 mg CU 32085 once a day was sufficient to maintain Prl levels within the normal range in 16 patients. Side-effects were similar in nature and frequency to those induced by bromocriptine and seemed to be dose-dependent. They can be avoided by slowly increases of dose at initiation of treatment.