FIGURE 1.

Mechanism of action of drugs for hyperkalemia. C, calcium; H, hydrogen; K, potassium; M, magnesium; N, sodium; S, sorbitol; TAL, thick ascending limb. (a) Shift K⁺ into cells. (1) Insulin and β₂ agonists both stimulate the Na+/K+ ATPase facilitating extracellular potassium exchange for intracellular sodium. (2) Sodium bicarbonate stimulates the HCO₃⁻/K⁺ cotransporter facilitating HCO₃⁻ and K⁺ cotransport in exchange for intracellular sodium. (b) Enhance K⁺ removal. (3) Via urine: Loop diuretics act on the thick ascending limb of the loop of Henle inhibiting the Na⁺–K⁺–2Cl⁻ cotransporter resulting in decreased sodium and potassium reabsorption. (4) Via gastrointestinal lumen: sodium zirconium cyclosilicate, patiromer and sodium polystyrene sulfate work by binding K⁺ in exchange for hydrogen, calcium and sodium (respectively) in the gastrointestinal lumen, allowing more potassium excretion.