Hyperprolactinemia and impotence: why, when and how to investigate.

The contribution of hyperprolactinemia to erectile disorders has not been clarified. Modest elevations of serum prolactin occur after administration of drugs that by themselves affect erectile function. Prolactinomas produce marked elevations of the hormone and invariably are accompanied by hypogonadotropic hypogonadism. Among 1,236 consecutive impotent patients investigated at our center 5.3% had serum levels of prolactin greater than normal. Only 34 of the 66 hyperprolactinemic patients were available for analysis. The etiology of the hyperprolactinemia in this group was pituitary adenoma in 14.7%, drug-induced in 29%, chronic renal failure in 6%, laboratory error in 2.9% and idiopathic in 47.1%. Medical management has a high degree of success but simply lowering the levels of prolactin is not invariably accompanied by restoration of function.