What is a key safety consideration when adding spironolactone or eplerenone to therapy in HF?

• A. Hyperkalemia; monitor potassium and renal function.
• B. Hypernatremia; monitor sodium.
• C. Hypokalemia; monitor calcium.
• D. Hypotension; monitor liver enzymes.

Answer: (A)

Spironolactone and eplerenone are aldosterone antagonists used in heart failure to reduce mortality, but their key safety risk is hyperkalemia. By blocking aldosterone, these drugs reduce potassium wasting in the distal nephron, leading to potassium retention. In heart failure patients, especially those also on ACE inhibitors or ARBs or with impaired kidney function, potassium can rise quickly. That’s why monitoring serum potassium and renal function (creatinine/eGFR) and adjusting therapy as needed is essential. Hypernatremia isn’t the primary concern here, and while hypotension can occur, the most important safety consideration to watch for is elevated potassium.