Potassium supplements are used as a source of potassium cation for treatment or prevention of potassium depletion in patients in whom dietary measures are inadequate. Conditions which may indicate or result in potassium deficiency include vomiting, diarrhea, drainage of GI fluids, hyperadrenalism, malnutrition, debilitation, prolonged negative nitrogen balance, prolonged parenteral alimentation without addition of potassium, dialysis, metabolic alkalosis, metabolic or diabetic acidosis, GI tract abnormalities which result in poor absorption, certain renal diseases, and familial periodic paralysis characterized by hypokalemia. Potassium should be included in long-term electrolyte replacement regimens and has been recommended for routine prophylactic administration following surgery after adequate urine flow has been established. Administration of certain drugs including thiazide diuretics, carbonic anhydrase inhibitors, furosemide, ethacrynic acid, some corticosteroids, corticotropin, aminosalicylic acid, and amphotericin B may sometimes result in potassium depletion which may warrant potassium replacement therapy. Ingestion of potassium-rich foods and/or use of potassium-containing salt substitutes may prevent potassium depletion in patients receiving potassium-depleting drugs; however, judicious prophylactic administration of potassium may be advisable in selected patients during prolonged diuretic or corticosteroid therapy, especially if they are digitalized.
Potassium chloride is usually the salt of choice in the treatment of potassium depletion, since the chloride ion is required to correct hypochloremia which frequently accompanies potassium deficiency. In addition, hypochloremia may develop if the citrate, bicarbonate, gluconate, or another alkalinizing salt of potassium is administered, particularly in conjunction with chloride-restricted diets. In the rare instances in which metabolic acidosis exists concurrently with potassium depletion (e.g., renal tubular acidosis), alkalinizing salts of potassium are preferred.
Inadequate dietary intake of potassium may play an important role in the development of hypertension, and high dietary intake of potassium (e.g., with supplementation) may protect against the development of high blood pressure and improve blood pressure control in patients with hypertension. As a result, most experts currently recommend that an adequate intake of potassium (about 50-90 mEq daily) be maintained in hypertensive patients as part of lifestyle modifications, particularly in those unable to adequately reduce their sodium intake. Adequate intake of potassium also should be considered as a means of preventing the development of hypertension. Food sources high in potassium such as fruits and vegetables preferably should be used. Alternatively, potassium supplements or salt-substitutes or potassium-sparing diuretics can be used, particularly in patients receiving kaliuretic diuretics. In pooled analysis of data from 33 randomized controlled trials in which potassium supplementation was the only difference between intervention and control groups, such supplementation was associated with a reduction in mean systolic blood pressure of 3.11 mm Hg and a reduction in mean diastolic blood pressure of 1.97 mm Hg. The effects of potassium supplementation appeared to be particularly evident in patients exposed to high sodium intake.
Potassium salts may be used cautiously to abolish arrhythmias of cardiac glycoside toxicity precipitated by a loss of potassium. It has been reported that elevation of plasma potassium concentrations by 0.5-1.5 mEq/L or to the upper limits of normal may be useful in the management of tachyarrhythmias following cardiac surgery. This regimen should not be used in patients with atrioventricular block, however, since potassium may further impair nodal conduction.
Limited data suggest that potassium may be useful in the treatment of thallium poisoning; however, such treatment is limited by the amount of thallium that can be released into the blood without worsening cerebral symptoms.