Cabergoline: A first-choice treatment in patients with previously untreated prolactin-secreting pituitary adenoma

Cabergoline (CAB) treatment is an effective, safe and well tolerated approa ch for hyperprolactinemia. We investigated the efficacy of 24-month treatme nt with CAB in 37 patients with previously untreated PRL-secreting pituitar y adenoma and evaluated the hormonal and neuroradiological changes after th e discontinuation of long-term therapy. Eleven patients with macroprolactin oma (1M/10F) and 26 with microprolactinoma (4M/22F) started treatment takin g 0.25 mg CAB twice a week for 4 weeks. The dose was increased stepwise in 0.5 mg increments until reaching lowest maximally effective and tolerated d ose. CAB was withdrawn before the end of the study in 6 women who became pr egnant and in one patient who showed a slight increase of the macroadenoma at MRI. During treatment, PRL levels decreased significantly in macro (11.1 +/-1.1 vs 407.8+/-98.3 mu g/l, p<0.001) and microprolactinomas (11.1+/-1.6 vs 193.8+/-23.4 mu g/l, p<0.05) and normalized in all macro and in 23/26 mi croprolactinomas. In 3 cases PRL levels decreased but did not normalize bec ause the appearance of side effects, such as nausea or hypotension, prevent ed the increase of the dose of CAB. The effective dose of drug correlated s ignificantly with basal serum PRL levels (p<0.05) and with the pituitary tu mor size (p<0.05). A significant decrease of the mean adenoma size was evid ent for macro (6.9+/-1.8 vs 16.0+/-1.8 mm, p<0.001) and microprolactinomas (3.0+/-0.5 vs 6.5+/-0.4 mm, p<0.001) at MRI. The tumor disappeared in 4 mac roadenomas and in 11 microadenomas after 12 months of treatment. CAB withdr awal was followed by serum PRL increase in 13 cases after 3 months, in 6 af ter 6 months, in 2 after 9 months, and in one patient at the 12(th) month. Five patients showed normoprolactinemia with negative MRI after one year. R egular menses were restored in 7/10 macroprolactinomas and in all oligo-ame norrhoic patients with microadenoma; serum testosterone levels normalized i n 2/3 hypogonadic men. Five out of 6 women become pregnant and had uneventf ul pregnancies which resulted in deliveries of normal babies. In conclusion , this study confirms the effectiveness and safety of CAB for patients with PRL-secreting pituitary adenoma and suggests that it can be considered a f irst choice treatment. (C) 1999, Editrice Kurtis.