Switching from High-Dose Spironolactone to Eplerenone in Idiopathic Hyperaldosteronism

Introduction to Switching Strategy

The American College of Cardiology recommends switching from spironolactone to eplerenone in patients with idiopathic hyperaldosteronism, with a conversion ratio of approximately 1:1 for total daily dose, and discontinuing concomitant potassium supplementation immediately, with monitoring of serum potassium and creatinine at 1 week and 4 weeks post-switch 1

The FDA indicates that eplerenone often requires twice-daily dosing for adequate blood pressure lowering, making BID dosing appropriate for high total daily requirements 3, 4
If eGFR is 30-49 mL/min/1.73m², consider starting at 50mg BID and titrating up 1

Intensive early monitoring is recommended to detect hyperkalemia or renal dysfunction, with checks of potassium and creatinine at 1 week and 4 weeks after the switch 1
If potassium rises to >5.5 mmol/L, reduce eplerenone dose by 50% (to 50mg BID), and if potassium reaches >6.0 mmol/L, stop eplerenone immediately and monitor closely 1, 5
Never combine eplerenone with ACE inhibitor + ARB together, as this dramatically increases hyperkalemia risk 3, 6

The European Society of Cardiology notes that eplerenone eliminates the anti-androgenic side effects that occur with spironolactone, such as gynecomastia, erectile dysfunction, and menstrual irregularities 5
Avoid NSAIDs and COX-2 inhibitors, which worsen renal function and increase hyperkalemia risk with aldosterone antagonists 6