Definition:

• Potassium is considered to be a “nutrient of public health concern” according to the 2015-2020 Dietary Guidelines for Americans since its underconsumption in the US population is associated with adverse health effects (hypertension and cardiovascular disease).
• Normal body function depends on tight regulation of potassium concentrations both inside and outside of cells.
• Low potassium concentration in the blood (hypokalemia) can result in muscular paralysis or abnormal heart rhythms and can be fatal. Hypokalemia is usually due to excessive loss of potassium as with prolonged vomiting or diarrhea, use of diuretics, or kidney disease.
• Chronic hypertension damages the heart, blood vessels, and kidneys, thereby increasing the risk of cardiovascular disease. Increasing dietary potassium intake may help lower blood pressure in normotensive and hypertensive individuals.
• Results from observational studies reported higher dietary potassium intakes to be associated with lower risks of stroke and kidney stone formation. Evidence of the role of potassium intake in promoting bone health remains weak.
• Good dietary sources of potassium include fruit and vegetables, some nuts and seeds, and dairy products.
• Safety concerns with consuming potassium are limited in healthy people because the kidneys adjust urinary potassium excretion to potassium intake. Concomitant use of potassium supplements with certain drugs can increase the risk of potassium toxicity.
• Magnesium is required for the uptake of potassium from serum into cells, and intracellular potassium deficiency cannot be adequately corrected when magnesium deficiency is also present.

Drug interactions

• Amphotericin B: Treatment with amphotericin B has been reported to cause hypomagnesemia and hypokalemia.
• Certain antibiotics including carbenicillin, polymyxin B, nafcillin, and penicillin; combination therapy with carbenicillin, gentamicin, and methicillin or nafcillin; and combination therapy with gentamicin and cephalexin have been reported to cause hypokalemia.
• Beta-2 agonists: Administration of the beta-2 agonists, salbutamol and rimiterol, decreased plasma potassium and magnesium levels in healthy volunteers. The combination of a beta-2 agonist and theophylline may produce a greater degree of potassium and magnesium deficiency than would a beta-2 agonist alone. Deficiencies of potassium and magnesium might increase the risk of cardiac arrhythmias and sudden death in asthmatic patients treated with beta-2 agonists.
• Deficiencies of potassium or magnesium increase the toxic effects of digoxin.
• Thiazide diuretics (e.g., hydrochlorothiazide, chlorthalidone) and loop diuretics (e.g., furosemide, bumetanide) increase urinary excretion of potassium. Potassium depletion resulting from long-term diuretic use may be a contributing factor to some of the adverse effects of diuretics, such as muscle cramps, cardiac arrhythmias, and impaired glucose tolerance. In contrast, potassium-sparing diuretics (e.g., triamterene, spironolactone) decrease urinary potassium excretion, potentially leading to hyperkalemia. The addition of a potassium-sparing diuretic may prevent potassium depletion in patients taking a thiazide or loop diuretic; however, the effect of combining these drugs can vary from one patient to another. The effects of various diuretics on urinary magnesium excretion are similar to their effects on potassium excretion. Magnesium is required for the uptake of potassium from serum into cells, and intracellular potassium deficiency cannot be adequately corrected when magnesium deficiency is also present. Because both deficiency and excess of potassium and magnesium can have deleterious consequences, potassium and magnesium levels should be monitored in patients taking diuretics.
• Circumstantial evidence suggests that suboptimal potassium status can contribute to the development of drug-induced myalgia in patients taking statin drugs.
• Administration of theophylline may deplete potassium and magnesium, which might increase the risk of certain adverse effects of theophylline, including cardiac arrhythmias. The combination of theophylline and a beta-2 agonist may produce a greater degree of potassium and magnesium depletion than would either of these drugs alone.

Dosage and administration

• The adequate intake (AI) for potassium is 2,600 mg/day for women and 3,400 mg/day for men. The AI for each age/life stage group was set based on the level of intake reported in apparently healthy populations.
• Safety concerns with consuming potassium are limited in healthy people because the kidneys adjust urinary potassium excretion potassium intake. Concomitant use of potassium supplements with certain drugs can increase the risk of potassium toxicity.