Eplerenone Dosage
Start eplerenone at 25 mg once daily and titrate to a target of 50 mg once daily within 4 weeks, with dose adjustments based on serum potassium levels and renal function. 1
Initial Dosing Strategy
The starting dose depends on clinical context:
- Standard initiation: 25 mg once daily for most patients 2, 1
- Alternative initiation: 25 mg twice daily or 50 mg twice daily for severe primary aldosteronism with profound hypokalemia 2
- Hypertension: May start at 50 mg once daily 1
For patients with eGFR 30-49 mL/min/1.73 m²: Maximum dose should not exceed 25 mg daily, as this lower dose is equally effective as 50 mg in patients with normal renal function but carries lower risk of adverse events 3
Titration Protocol
Target dose: 50 mg once daily, achieved within 4 weeks as tolerated 1
For hypertension with inadequate response at 50 mg daily, increase to 50 mg twice daily. Do not exceed 100 mg total daily dose - higher doses provide no additional blood pressure benefit but increase hyperkalemia risk 1
For primary aldosteronism, titrate in 25-100 mg increments every 8-12 weeks based on blood pressure control and renin suppression 2
Potassium-Based Dose Adjustments
Follow this algorithm strictly 1:
| Serum Potassium (mEq/L) | Action |
|---|---|
| <5.0 | Increase: 25 mg every other day → 25 mg daily → 50 mg daily |
| 5.0-5.4 | No adjustment needed |
| 5.5-5.9 | Decrease: 50 mg daily → 25 mg daily → 25 mg every other day |
| ≥6.0 | Withhold immediately; restart at 25 mg every other day only when K+ <5.5 |
Monitoring Requirements
Critical monitoring schedule 1:
- Before initiation: Measure serum potassium and creatinine
- Within first week: Recheck potassium
- At 1 month: Recheck potassium after any dose adjustment
- Every 2-3 months: During titration phase 2
- Annually: Once stable dose achieved 2
Additional monitoring needed within 3-7 days if patient starts moderate CYP3A4 inhibitors (erythromycin, verapamil, fluconazole) or ACE inhibitors/ARBs 1
Special Populations and Contraindications
Renal impairment considerations:
- eGFR ≥50 mL/min/1.73 m²: Standard dosing up to 50 mg daily
- eGFR 30-49 mL/min/1.73 m²: Maximum 25 mg daily 3
- eGFR <30 mL/min/1.73 m²: Avoid use - contraindicated due to severe hyperkalemia risk 4
Drug interactions: When taking moderate CYP3A4 inhibitors, do not exceed 25 mg once daily (heart failure) or 25 mg twice daily maximum (hypertension) 1
Baseline potassium >4.35 mmol/L: Higher risk of developing hyperkalemia; consider dietary sodium restriction and more frequent monitoring 5
Maximum Dosing
- Heart failure post-MI: 50 mg once daily maximum 1
- Hypertension: 100 mg daily (50 mg twice daily) maximum 1
- Primary aldosteronism: 200-300 mg daily in divided doses maximum 4
Critical Safety Points
Discontinue potassium supplements at days 2-4 after starting eplerenone in most patients, as normokalemia typically occurs within 3-5 days 2. Only continue supplements in severe hypokalemia with very frequent monitoring.
GFR may decrease in the first days to weeks after initiation - this usually represents treatment efficacy rather than adverse effect and typically stabilizes long-term 2. However, if progressive decline occurs, discontinue ACE inhibitors/ARBs and consider nephrology referral.
Dietary sodium restriction to <5 g/day is essential - high salt intake is the most common reason for apparent treatment failure 2