Verapamil-induced hyperprolactinemia complicated by a pituitary incidentaloma

To describe a patient with an incidental pituitary lesion who experienced verapamil-induced hyperprolactinemia.

A patient experiencing impotence was found to have increased prolactin and low testosterone concentrations. Verapamil as a cause for his increased prolactin concentration was not considered initially. The patient underwent extensive testing to rule out a pituitary tumor. Magnetic resonance imaging showed a 6-mm lesion consistent with a pituitary microadenoma that had remained unchanged for 6 months. Verapamil therapy was discontinued and within 1 month the patient's prolactin concentration decreased from 46.8 to 14.4 micrograms/L, and has remained within normal limits.

We reviewed reports of verapamil-induced hyperprolactinemia. This case was unique as this patient had an incidental pituitary lesion that was not responsible for increasing the prolactin concentration in our patient, but rather complicated the identification of a drug-induced disorder.

The failure to identify the hyperprolactinemic effect of verapamil may have resulted in performing unnecessary radiologic procedures in this patient. This case highlights the importance of obtaining a medication history in patients with hyperprolactinemia.