What is the recommended use and dosage of Aldactone (spironolactone) for medical conditions like heart failure, hypertension, and edema?

Aldactone (Spironolactone) Dosage and Use in Heart Failure, Hypertension, and Edema

Spironolactone should be initiated at 25 mg once daily for heart failure, 25-100 mg daily for hypertension, and 25-200 mg daily for edema, with careful monitoring of potassium levels and renal function to reduce mortality and morbidity. 1, 2

Heart Failure

Dosing Recommendations

• Initial dose: 25 mg once daily in patients with serum potassium ≤5.0 mEq/L and eGFR >50 mL/min/1.73m² 1
• Target dose: May increase to 50 mg once daily if tolerated 1
• For patients with eGFR between 30-50 mL/min/1.73m², start at 25 mg every other day due to hyperkalemia risk 1
• For patients who develop hyperkalemia on 25 mg daily, reduce to 25 mg every other day 1

Patient Selection

• Recommended for NYHA class III-IV heart failure patients with persistent symptoms despite ACE inhibitor and loop diuretic therapy 2
• Spironolactone should be initiated before digoxin as second-line therapy for persistent symptoms 2
• The RALES trial demonstrated significant mortality reduction in advanced heart failure patients 3

Monitoring

• Check serum potassium and renal function before initiation 4
• Monitor blood chemistry 12 weeks after initiation and 12 weeks after final dose titration 2
• Regular monitoring is essential as hyperkalemia rates in clinical practice (17.1%) are higher than in clinical trials 5

Hypertension

Dosing Recommendations

• Initial dose: 25-100 mg daily administered in single or divided doses 1
• Titration: Adjust dose at two-week intervals based on blood pressure response 1
• Maximum dose: Doses greater than 100 mg/day generally do not provide additional blood pressure reduction 1
• Particularly effective in resistant hypertension 4

Edema (Including Cirrhosis)

Dosing Recommendations

• Initial dose: 100 mg daily (range 25-200 mg) in single or divided doses 1
• For cirrhosis: Initiate therapy in hospital setting and titrate slowly 1
• When used as sole diuretic agent, administer for at least five days before increasing dose 1

Administration Considerations

General Guidelines

• Can be taken with or without food, but should be consistent with respect to meals 1
• For all indications, aim for the target dose or highest tolerated dose 2
• Remember that some spironolactone is better than none when full doses cannot be tolerated 2

Contraindications and Cautions

• Avoid in patients with significant renal dysfunction (creatinine >2.5 mg/dL) 2
• Use with caution in patients with baseline potassium >5.0 mmol/L 2
• Risk factors for hyperkalemia include: use of ACE inhibitors other than captopril, high ACE inhibitor doses, and baseline elevation of serum creatinine or potassium 6

Side Effects and Management

Common Side Effects

• Hyperkalemia: Occurs in 5-24% of patients depending on dose (higher with doses >25mg) 6
• Gynecomastia: Affects approximately 5.3% of male patients 5
• Renal function deterioration: Reported in 14.5% of patients 5
• Menstrual irregularities in women 3

Management of Side Effects

• For hyperkalemia (K+ ≥5.5 mEq/L): Reduce dose or discontinue 5
• For renal function deterioration (>30-50% increase in creatinine): Consider dose reduction 5
• For painful gynecomastia: May need to discontinue treatment 2
• Consider eplerenone as an alternative in patients with intolerable endocrine side effects 4

Clinical Pearls

• Lower doses (12.5-25 mg daily) are often effective and have lower risk of hyperkalemia 6
• In elderly patients, those with renal dysfunction, or potassium >4.5 mmol/L, lower doses (approximately 20 mg/day) are typically used 7
• Discontinuation rates in high-risk groups can reach 30% during the first year of treatment 7
• Even at lower than target doses, spironolactone maintains efficacy in reducing heart failure hospitalizations and cardiovascular death 7
• Continuing low-dose spironolactone is preferable to discontinuation in patients unable to tolerate target doses 7