Drug treatment of hyperprolactinemia

Abstract

Medical treatment of hyperprolactinemia is based upon use of dopamine agonists (DA): bromocriptine, lisuride, quinagolide and cabergoline. In over 80% of cases, these drugs induce normal prolactinemia and ovulatory cycles. In resistant cases, the DA should be changed. Tolerance may occasionally be poor, particularly with bromocriptine, which appears less well-tolerated than quinagolide and than cabergoline above all. In the event of intolerance to a given DA, another should be tried. In patients with macroprolactinoma treated with DA, MRI monitoring should be carried out after 3 months of treatment to verify tumor size reduction, then after 1 year, yearly for the next 5 years and once every 5 years if adenoma size is stable. In cases of microprolactinoma, control under treatment is pointless. MRI may be performed after 1 year and then after 5 years. Once normal prolactin levels have been achieved, attempts may be made to stop the treatment. When a prolonged treatment is interrupted, especially with cabergoline, progressive increase in serum prolactin and return of hyperprolactinemia symptoms are seen in only around 20-30% of cases, particularly when residual adenoma exists after prolonged treatment. Nevertheless, prolactin levels should continue to be monitored after discontinuation of DA, possibly with MRI monitoring, since prolactin levels may rise again after a number of months or years. When normal prolactin levels have been achieved with DA, another solution consists in reducing the dose or dosing frequency of DA in steps to the lowest effective dose consistent with maintenance of normal prolactin levels and stable adenoma size. For drug-induced hyperprolactinemia, where the causative medication cannot be withdrawn, it is often pointless and possibly even dangerous to administer a DA. It is therefore necessary to check for absence of pituitary adenoma and where necessary, begin treatment with sex steroids so as to ensure satisfactory impregnation with sex steroids and avoid osteoporosis. For macroprolactinoma, the first-line treatment is drug therapy with DA. At present, there is no evidence to suggest that prior treatment with DA can modify the outcome of surgery. With microprolactinoma, DA treatment offers a good first-line therapeutic option but surgery may also be useful. DAs for microprolactinoma may be withdrawn after menopause.