What is the recommended dose of spironolactone (aldosterone antagonist) for patients with heart failure?

Recommended Dosage of Spironolactone for Heart Failure

The recommended starting dose of spironolactone for heart failure is 25 mg once daily, with a target dose of 25-50 mg once daily, particularly for patients with NYHA class III-IV heart failure. 1

Dosing Guidelines

• Start with 25 mg once daily (or on alternate days in patients at higher risk of hyperkalemia) 1
• Target maintenance dose is 25-50 mg once daily 1
• For patients with severe heart failure (NYHA class III-IV), spironolactone is indicated as second-line therapy after ACE inhibitors and beta-blockers 1

Monitoring Requirements

• Check serum potassium and creatinine at the following intervals:

  • After 1,4,8, and 12 weeks of initiation 1
  • At 6,9, and 12 months 1
  • Every 6 months thereafter 1

• More frequent monitoring schedule recommended by European Society of Cardiology:

  • Check serum potassium and creatinine after 4-6 days of initiation 1
  • If increasing dose, recheck after 1 week 1

Dose Adjustment Based on Laboratory Values

• If potassium rises to between 5.0-5.5 mmol/L, reduce dose by 50% (to 25 mg on alternate days) 1
• If potassium rises to ≥5.5 mmol/L, stop spironolactone 1
• If creatinine rises to >221 μmol/L (>2.5 mg/dL), reduce dose and monitor closely 1
• If potassium rises to >6.0 mmol/L or significant renal dysfunction develops, seek specialist advice 1

Clinical Evidence Supporting These Recommendations

• The landmark RALES study demonstrated that low-dose spironolactone (25 mg daily) reduced mortality by 30% and hospitalizations by 35% in patients with severe heart failure (NYHA class III-IV) 2
• Spironolactone improves survival, reduces hospital admissions, and improves NYHA functional class when added to standard therapy (diuretics, ACE inhibitors, and in some cases beta-blockers) 1

Important Considerations

• Spironolactone is primarily indicated for patients with moderately severe to severe heart failure (NYHA class III-IV) 1
• Higher doses (50-200 mg) may be used in selected patients with advanced heart failure but require more careful monitoring 3
• Common side effects include gynecomastia or breast pain (reported in 10% of male patients) 2
• Major concern is hyperkalemia, though this was uncommon in the RALES trial at the recommended doses 1

Drug Interactions to Monitor

• Use caution when combining with:
  • ACE inhibitors, angiotensin receptor blockers, other potassium-sparing diuretics 1
  • Potassium supplements 1
  • NSAIDs (advise patients to avoid over-the-counter NSAIDs) 1
  • "Low salt" substitutes with high potassium content 1

Patient Instructions

• Explain that treatment improves symptoms, prevents worsening of heart failure, and increases survival 1
• Symptom improvement typically occurs within a few weeks to months of starting treatment 1
• Temporarily stop spironolactone during episodes of diarrhea or vomiting and contact physician 1
• Monitor for signs of hyperkalemia (weakness, fatigue, paresthesia) 1