Hyperprolactinemia and galactorrhea associated with marijuana use

A 23-year-old woman presented with breast tenderness and bilateral nipple discharge. She was found to have a prolactin level of 136.9 ng/mL, negative serum pregnancy test, normal pituitary anatomy on imaging, and no other discernible cause for the hyperprolactinemia. Bromocriptine treatment normalized the prolactin and considerably reduced the galactorrhea. After 3 months of therapy, the patient revealed that she had been a heavy weekend marijuana user for more than 1 year but had stopped completely recently. Bromocriptine was discontinued while the patient abstained from further marijuana smoking. One month later, the prolactin level was normal and no breast abnormalities or nipple discharge was evident. In conclusion, periodic, heavy, and regular marijuana use can cause clinically significant hyperprolactinemia over the long term that can present a diagnostic dilemma and lead to unnecessary medical therapy. It should be considered as a reversible cause of elevated prolactin and should be kept in mind in the differential diagnosis of galactorrhea in women.