Which medication class can cause hyperkalemia and requires potassium monitoring in heart failure?

• A. Aldosterone Antagonists (Spironolactone or Eplerenone)
• B. ACE Inhibitors
• C. Loop Diuretics
• D. Calcium Channel Blockers

Answer: (A)

Aldosterone antagonists raise potassium because they block aldosterone’s effect in the collecting ducts, where aldosterone normally promotes potassium secretion. In heart failure, this blockade reduces sodium reabsorption and water retention but preserves or increases potassium, leading to hyperkalemia. Because of this risk, these medications require regular potassium (and kidney function) monitoring, especially after starting therapy or adjusting the dose or when used with other potassium-raising drugs. While ACE inhibitors can also cause hyperkalemia, the class identified here is the one most characteristically associated with potassium-sparing effects in heart failure and thus requires ongoing potassium checks. Loop diuretics tend to cause low potassium, and calcium channel blockers don’t typically cause hyperkalemia in this context.