What electrolyte abnormality is a key safety concern with MRA therapy in HF?

• A. Hyperkalemia.
• B. Hypernatremia.
• C. Hypokalemia.
• D. Hypercalcemia.

Answer: (A)

The key idea is that mineralocorticoid receptor antagonists raise the risk of high potassium. Blockade of aldosterone in the kidney reduces potassium excretion in the distal nephron, so potassium can accumulate, especially in patients with reduced kidney function or those already on other potassium-raising drugs like ACE inhibitors, ARBs, or ARNI. This hyperkalemia can be dangerous because it can disrupt heart conduction and trigger dangerous arrhythmias. That’s why monitoring is essential: check baseline potassium and creatinine, recheck potassium (often within a few days to a week after starting or adjusting the dose), and continue periodic monitoring. Manage risk by avoiding concurrent potassium supplements or other potassium-sparing meds when possible, and adjust therapy if potassium rises or kidney function worsens. Other electrolyte shifts can occur in HF, but hyperkalemia is the primary safety concern with MRAs.