Serum prolactin and ovarian function after discontinuation of drug treatment for hyperprolactinaemia: a study with bromocriptine and metergoline.

Serum prolactin (PRL) was estimated for up to 2 months after discontinuation of therapy with either bromocriptine (n = 33; 15 with idiopathic disease, 12 with pituitary microadenoma, and six with macroadenoma) or metergoline (n = 23; 11 with idiopathic disease, and 12 with microadenoma) that had been administered for 8-30 months. Only five patients treated with bromocriptine and two treated with metergoline had PRL levels that remained normal or below 50% of pretreatment values. Among the patients followed-up for up to 12 months, four showed a fall in PRL at 3-4 months, but this was followed by a rise in one patient. Five patients showing persistently lower or normal PRL after drug withdrawal were retested with thyrotrophin-releasing hormone; the two responsive women also had a normal response before treatment. Of 10 patients followed for 9 months, three had persistently normal PRL levels. Amenorrhoea and anovulation recurred, with some delay, in all the patients showing PRL rebound except one. Medical treatment of hyperprolactinaemia only rarely results in permanent benefit.