Effect of amiloride on metabolic alkalosis and hypokalaemia after cardiopulmonary bypass surgery.

This study was undertaken to investigate the effects of the potassium-retaining diuretic, amiloride, on the potassium balance and on the alkalosis which occurs in patients after open-heart surgery. Patients who had had valve replacement operations were divided randomly into two groups, one of which received Io mg amiloride daily in the postoperative period. Patients who were given amiloride needed less potassium supplementation than those in the control group (P< o oo5) and yet maintained significantly higher plasma potassium levels (P< o os). This small dose of amiloride also appeared to have some effect in reducing the alkalosis. It is concluded that amiloride is a potentially useful drug after cardiac surgery.