Conversion of Eplerenone to Spironolactone

Dosing Equivalence

• The American College of Cardiology recommends a 2:1 ratio when converting from eplerenone to spironolactone, with 50 mg of eplerenone being equivalent to 25 mg of spironolactone 1
• For patients previously on eplerenone, the standard maintenance dose is equivalent to spironolactone, with 50-100 mg of eplerenone once daily being equivalent to 25-50 mg of spironolactone once daily 1

Monitoring Requirements After Conversion

• The European Society of Cardiology recommends checking renal function and serum electrolytes before initiating spironolactone, and rechecking at 1 and 4 weeks after conversion 2, 3
• Continue monitoring at 1, 2, 3, and 6 months after achieving maintenance dose, then every 6 months thereafter 2, 3

Side Effect Considerations

• Spironolactone causes breast discomfort and enlargement in approximately 10% of male patients compared to minimal occurrence with eplerenone 2, 3

Precautions When Converting

• Avoid spironolactone in patients with serum potassium >5.0 mmol/L or severe renal impairment (eGFR <30 mL/min/1.73 m²) 1
• For patients with moderate renal impairment (eGFR 30-49 mL/min/1.73 m²), reduce the starting dose to 12.5-25 mg once daily 1
• Monitor for hyperkalemia - if potassium rises to >5.5 mmol/L, halve the dose of spironolactone 2, 3
• If potassium rises to >6.0 mmol/L, stop spironolactone immediately 2, 3

Clinical Pearls

• Consider patient-specific factors when converting, such as sex (males more prone to gynecomastia with spironolactone) and renal function 2, 3