Drug Associations in Hypokalemia

To the Editor.—  In their recent article in the Archives (139:978-980,1979), Dr Lawson and his colleagues suggest that hypokalemia is unusually frequent in patients with acute myeloblastic leukemia (AML). At present, the most common form of therapy for this disease includes daunorubicin hydrochloride, thioguanine, and cytarabine. None of these drugs is associated with abnormal potassium metabolism or affects renal function.¹ On the other hand, most patients with AML are treated with broad-spectrum antibiotics for febrile episodes occurring during the period of granulocytopenia that follows chemotherapy. Carbenicillin disodium and amphotericin B are among the antibiotics frequently used when severe infections develop. Both substances are associated with hypokalemia, caused by increased sodium load and metabolic alkalosis in the case of carbenicillin,² and distal renal tubular lesions in the case of amphotericin B.³ Before theorizing the existence of an idiopathic mechanism for hypokalemia in AML, I believe the authors should indicate whether