Moduretic-induced metabolic acidosis and hyperkalaemia.

A patient who developed significant metabolic acidosis and severe hyperkalaemia while taking Moduretic (amiloride and hydrochlorothiazide) is reported. During the period of hyperkalaemia (maximum potassium 7-6 mmol/l) the patient's whole body potassium content was normal. His acid-base balance and serum potassium returned to normal some 10 days after stopping the drug. The possible mechanism of acidosis and hyperkalaemia in this patient is discussed.