Comparison of the effects of cabergoline and bromocriptine on prolactin levels in hyperprolactinemic patients.

OBJECTIVE It is well known that bromocriptine has a suppressive effect on the prolactin release in hyperprolactinemic patients. But it also has some adverse effects. The new, long-acting dopaminergic drug, cabergoline, has been reported to be an effective agent in these patients. However, there are relatively few reports comparing the beneficial and adverse effects of these drugs in the treatment of hyperprolactinemic patients. Therefore, here we studied and compared the efficacy and tolerability of cabergoline with bromocriptine in hyperprolactinemic patients. PATIENTS Seventeen patients (7 with microprolactinoma, 4 with macroprolactinoma, 6 with idiopathic hyperprolactinemia) were given bromocriptine at a dose of 2.5 mg (or 5 mg for macroprolactinomas) twice daily, and 17 patients (8 with microprolactinoma, 4 with macroprolactinoma, 5 with idiopathic hyperprolactinemia) were given cabergoline at a dose of 0.5 mg twice weekly for 12 weeks. RESULTS At the end of the study, the prolactin reduction was significantly greater in the cabergoline group than in the bromocriptine group (-93 vs. -87.5 %, respectively, p < 0.05). Normalization of prolactin levels was achieved in 10 of 17 patients (59%) in the bromocriptine group, and in 14 of 17 patients (82%) in the cabergoline group (p = 0.13). Two patients (50%) with macroprolactinoma in the bromocriptine group and three patients (75%) with macroprolactinoma in the cabergoline group demonstrated a normalization of their serum prolactin levels. Adverse events were noted in 53% of bromocriptine patients and in 12% of cabergoline patients (p < 0.01). CONCLUSION These data indicate that cabergoline is a very effective agent for lowering the prolactin levels in hyperprolactinemic patients and that it appears to offer considerable advantage over bromocriptine in terms of efficacy and tolerability.