Hyponatremia Due to Sulfonylurea Compounds

Abstract

In a 68-yr-old female with diabetes mellitus and idiopathic cerebral atrophy, therapeutic doses of chlorpropamide or tolbutamide induced a hyponatremic syndrome identical with that of inappropriate secretion of ADH (serum Na 117 mEq/1). Metabolic studies revealed that the hyponatremia was due in part to negative sodium balance. There was no evidence of acute fluid retention since body weight, free water clearance and isotopic extracellular fluid volume were identical during control and drug periods. Diuresis was also absent, indicating inappropriate ADH activity during sulfonylurea-induced hyponatremia. Physicians using sulfonylurea drugs in the management of diabetes mellitus must be alert to the possible complication of hyponatremia.