Failure of bromocriptine to suppress prolactin in majeptil-induced hyperprolactinemia

A case of hyperprolactinemic anovulation with amenorrhea and galactorrhea, due to Phenothizine derivative (Majeptil) is presented. Treatment with bromocriptine, 2.5 mg b.i.d., p.o., or L-Dopa, 500 mg, p.o., did not suppress serum prolactin and menstrual cycle was not resumed. Pituitary prolactin response to TRH and Pituitary LH and FSH response to LHRH were found to be normal. It seems that at the dose used, bromocriptine (a dopaminergic agonist) cannot counteract the phenothiazine induced hyperprolactinemia. Hence, it is not effective in induction of ovulation while the patient is under phenothiazine treatment.