Diuretics and potassium metabolism: A reassessment of the need, effectiveness and safety of potassium therapy

Abstract

In the past decade approximately forty-eight billion milliequivalents of a single oral potassium chloride preparation have been produced and sold by a single pharmaceutical manufacturer (WETTER MS, Ciba Pharmaceutical Co., June, 1976, personal communication). Precise figures for the total quantity of potassium prescribed annually are not available, but an estimate of 20 to 30 billion milliequivalents is probably reasonably accurate. It is also a reasonable assumption that a substantial fraction of this electrolyte supplement is prescribed to prevent or to treat the hypokalemia and potassium deficiency generally thought to result from diuretic therapy. The conclusion seems inescapable, considering the enormous amounts of potassium prescribed, that the majority of physicians feel confident that routine treatment with an oral potassium preparation is warranted in patients receiving diuretic therapy. This opinion is maintained even though several recent studies have raised serious question about the need for such therapy and have also pointed out the potential risk of treatment [1–6]. Indeed, the casual approach to the administration of potassium contrasts sharply with the cautious approach to the use of a drug such as chloramphenicol, even though the ratio of risk to benefit is probably considerably higher for potassium salts as compared to the antibiotic. The purpose of this review is to discuss the magnitude of potassium deficiency in patients receiving diuretics, the influence of diuretic-induced acid-base derangements on potassium balance, the necessity and effectiveness of therapy with potassium salts and potassium conserving drugs and, finally, the benefits and costs of therapy.