Decrease of prolactin by methysergide in amenorrheic hyperprolactinemic women.

The effect of methysergide (MES), a serotoninergic antagonist on prolactin (PRL) blood levels was studied in five hyperprolactinemic amenorrheic women. The drug was administered for five days at a daily dosage of 11.2 mg. MES decreased significantly the PRL blood levels in all subjects (p less than 0.01). Since the MES has been shown to have antiserotoninergic effects and since serotonin has been thought to be involved in the control of PRL release, the effects of MES in lowering PRL might be due to a decrease of serotonin tone.