Serum prolactin and ovarian function after discontinuation of drug treatment for hyper-prolactinaemia: 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 hyper-prolactinaemia only rarely results in permanent benefit.