Aldactone (Spironolactone) Should Be Held When GFR is Below 30 mL/min/1.73 m²
Spironolactone should be held when the glomerular filtration rate (GFR) is less than 30 mL/min/1.73 m² due to significantly increased risk of hyperkalemia and renal insufficiency 1.
Evidence-Based Recommendations for Spironolactone Use Based on GFR
Contraindications
- GFR < 30 mL/min/1.73 m²: Spironolactone is contraindicated due to high risk of life-threatening hyperkalemia 1
- Serum creatinine > 2.5 mg/dL in men or > 2.0 mg/dL in women: These levels typically correspond to GFR < 30 mL/min/1.73 m² and indicate contraindication 1
- Baseline serum potassium > 5.0 mEq/L: Regardless of GFR, spironolactone should not be initiated 1
Dosing Recommendations Based on GFR
- GFR ≥ 50 mL/min/1.73 m²: Standard dosing (25 mg once daily initially) 1, 2
- GFR 30-49 mL/min/1.73 m²: Reduced dosing (12.5-25 mg once daily or every other day) 1, 2
- GFR < 30 mL/min/1.73 m²: Hold medication 1
Monitoring Recommendations
When initiating spironolactone in patients with acceptable renal function:
- Check potassium and renal function within 2-3 days of initiation 1
- Recheck again at 7 days after initiation 1
- Monitor at least monthly for the first 3 months 1
- Continue monitoring every 3 months thereafter 1
- Implement more frequent monitoring when adding or increasing doses of ACE inhibitors or ARBs 1
Management of Hyperkalemia During Treatment
- Potassium 5.0-5.5 mEq/L: Continue spironolactone but monitor closely 1
- Potassium > 5.5 mEq/L: Reduce dose by half and monitor closely 1
- Potassium > 6.0 mEq/L: Discontinue spironolactone 1
Special Considerations
- Discontinue potassium supplements when initiating spironolactone 1
- Counsel patients to avoid high-potassium foods and NSAIDs 1
- Instruct patients to temporarily stop spironolactone during episodes of:
- Avoid triple therapy with ACE inhibitors, ARBs, and spironolactone due to extremely high hyperkalemia risk 1
Clinical Pearls and Pitfalls
- Despite the benefits of spironolactone in heart failure, the risk of hyperkalemia increases significantly when GFR falls below 30 mL/min/1.73 m² 3, 4
- In elderly patients or those with low muscle mass, serum creatinine may not accurately reflect GFR; direct GFR measurement is recommended to confirm it is > 30 mL/min/1.73 m² 1
- The risk of hyperkalemia increases progressively when serum creatinine is > 1.6 mg/dL 1
- While some studies suggest potential benefits of spironolactone in CKD patients 5, 6, the risk of adverse events is significantly amplified with declining renal function 7
The evidence is clear that spironolactone should be held when GFR falls below 30 mL/min/1.73 m² to prevent potentially life-threatening hyperkalemia and worsening renal function.