Sulfonamide-induced hypoglycemia in chronic renal failure.

Severe hypoglycemia with an inappropriately elevated insulin level occurred in a patient with chronic renal failure who was taking two tablets of sulfamethoxazole and trimethoprim twice a day for a urinary tract infection. Hypoglycemia was readily corrected with intravenous glucose and did not recur after discontinuation of the sulfonamide. Insulin and glucose determinations during a 48-hour fast while the patient was rechallenged with this compound, as compared with those obtained during a 72-hour fast performed 12 days after discontinuation of the therapy, suggest that the hypoglycemic episode was related to hyperinsulinemia probably induced by the sulfonamide. Other factors, including congestive heart failure, growth hormone deficiency, and hypoalaninemia might have contributed to the development of hypoglycemia in this patient.