Drugs and Pituitary Function

Many drugs, both prescription and illicit, can affect pituitary function. Drug withdrawal sometimes reverses these effects, but pituitary hypo- or hyperfunction may persist for the long term. Several therapies used in an acute setting can also impact the hypothalamic-pituitary axis. The list of potential "culprit" drugs is large and expanding; drugs such as opiates, anti-CTLA-4 antibody therapy, and tyrosine kinase inhibitor (TKI) inhibitors have been recently found to have profound effects on the pituitary axes. Many therapies, including antidepressants, antipsychotics, antihistamines, and proton-pump inhibitors can raise prolactin levels and a complete drug history is essential in the differential diagnosis of hyperprolactinemia, especially when it coincides with the presence of a small pituitary adenoma. Increased awareness of drug effects on the pituitary should prompt early screening, or, in the presence of suggestive symptoms and/or abnormal laboratory values, expeditious treatment for hypopituitarism. Familiarity with the spectrum of pituitary dysfunction attributed to acute and chronic drug therapies is paramount to endocrinologists, oncologists, pain specialists, psychiatrists, intensivists, and internal medicine specialists.