Drug attributed alterations in potassium handling in congestive cardiac failure.

Information from a comprehensive drug surveillance programme has been reviewed to give details of the frequency of drug-related hypo- and hyperkalaemia in a group of 3879 patients admitted to hospital with cardiac failure. Hypokalaemia was commoner in females, was unrelated to blood area concentration on admission and was twice as common amongst recipients of potassium-losing diuretics who did not take potassium supplements than amongst those who received potassium retaining diuretics. By contrast hyperkalaemia was strongly related to blood urea concentration on admission. It was also related to in-hospital diuretic therapy; being thrice as frequent amongst recipients of aldosterone antagonists than amongst those receiving potassium-losing diuretics without additional supplements. Life-threatening hypo- and hyper-kalaemia were rare in this group of patients with heart failure, occurring with approximately equal frequencies of about 2 per 1000 patients treated.