Megaloblastic Anemia Possibly Induced by Triamterene in Patients with Alcoholic Cirrhosis

Two patients are described who appeared to develop megaloblastic anemia during therapy with triamterene and hydrochlorothiazide, and both had low serum folate levels. One of these two patients was critically ill with this complication but survived when triamterene was stopped and folic and folinic acids were administered. Because triamterene has been shown to be a folic acid antagonist in vitro, we conclude that this drug may precipitate megaloblastic anemia in alcoholic cirrhosis by inhibiting the utilization of folic acid in the presence of low stores of folic acid.