Hyperprolactinemia in patients with renal insufficiency and chronic renal failure requiring hemodialysis or chronic ambulatory peritoneal dialysis

Hyperprolactinemia is common in patients with renal failure. Because radiographic contrast material given during a computed tomographic (CT) scan of the sella as part of the evaluation for prolactinoma worsens renal insufficiency, we attempted to define the point at which hyperprolactinemia becomes an expected finding in patients with renal insufficiency in this study. Of 59 patients with serum creatinine levels of 1.5 to 12 mg/dL, 16 (27.1%) were hyperprolactinemic. Of these 16, nine were not taking medications known to raise prolactin levels and their prolactin levels were less than 100 ng/mL. In the eight patients taking medications prolactin levels were much higher. In one patient the prolactin level fell from 2,210 to 100 ng/mL when methyldopa was discontinued. In patients with chronic renal failure prolactin levels were similar regardless of the method of dialysis. We conclude that in the absence of medications known to affect prolactin secretion, hyperprolactinemia occurs infrequently (18.3%) and, when it occurs, is mild (less than 100 ng/mL). Marked hyperprolactinemia may occur in patients taking such medications. These should be stopped and the prolactin level rechecked before a CT scan is performed.