Effect of treatment with bromocriptine on the size and activity of prolactin producing pituitary tumours

Abstract

Eleven patients with large prolactinomas were treated for 6 mo. with bromocriptine (7.5 mg/day). Nine had invasion of the sphenoidal sinus, one a visual field defect and one a secondary trigeminal neuralgia. At the end of the treatment period 8 of the first 9 patients showed radiographical signs of bone remodeling and/or actual reduction of the tumor size. The last 2 patients had complete disappearance of their symptoms. The remissions could be observed as early as 3 wk after the start of the treatment. Two patients suffered acute, reversible (partial in one case) episodes of loss of vision during the study. During the treatment the prolactin values decreased in all patients to an average of 1.7% of the baseline levels. There was a steep rise in the serum prolactin concentrations after withdrawal of the drug. After 1 mo. there was a plateauing at a high level, although lower than basal level. Libido and potency were restored in all 3 males studied. Two of the females experienced orgasm for the 1st time in their lives after some years of primary frigidity. It is concluded that bromocriptine reproducibly reduces the size of prolactinomas. This effect can be observed shortly after the beginning of the treatment and is at least partially reversible. Episodes of pituitary apoplexy may occur during the treatment of large tumors despite an otherwise favorable response.