Carbamazepine-related hyponatremia following cardiopulmonary bypass.

A 67-year-old man on long-term carbamazepine therapy underwent elective coronary artery bypass grafting. Following an initially uncomplicated recovery, he developed symptomatic hyponatremia. The symptoms and biochemical abnormality improved after gradual discontinuation of carbamazepine. We discuss the association between carbamazepine and hyponatremia and the causes of hyponatremia after cardiopulmonary bypass. Surgeons should consider stopping carbamazepine before operations with cardiopulmonary bypass.