Spironolactone: Clinical Overview
Primary Indications
Spironolactone is indicated for heart failure with reduced ejection fraction (HFrEF), primary aldosteronism, and resistant hypertension, with off-label use for acne in women. 1
Heart Failure with Reduced Ejection Fraction (HFrEF)
- NYHA class II-IV symptoms with LVEF ≤35% 1
- Requires optimal beta-blocker and ACE inhibitor (or ARB) therapy first 2
- Reduces mortality by 30% and HF hospitalizations by 35% 2
Primary Aldosteronism
- Drug of choice for medical management 3
- Controls BP in approximately 50% as monotherapy 3
- Maximum dose up to 400 mg/day 4
Acne (Off-Label)
- Effective for women of all ages with acne, not limited to adult women or lower facial distribution 5
- Starting dose typically 100 mg/day in evening 5
- Several months required for full effectiveness 5
Dosing Regimen
Heart Failure
Start with 12.5-25 mg once daily, titrate to target of 25-50 mg daily 1
- Initial dose: 25 mg once daily (or 12.5 mg if eGFR 30-49 mL/min/1.73 m²) 6
- Check potassium and renal function at 1 and 4 weeks after initiation 2
- Increase to 50 mg daily after 4-8 weeks if tolerated 2
- For marginal renal function (eGFR 30-49), consider every-other-day dosing initially 6
Primary Aldosteronism
Start 12.5-25 mg once daily, titrate gradually to maximum 100 mg/day 3
- In elderly or reduced kidney function: start 12.5 mg/day 4
- Maximum dose can reach 400 mg/day for resistant cases 4
- Single daily dosing due to prolonged pharmacological action 4
Acne
Start 100 mg once daily in evening, may increase to 200 mg/day 5
- Doses of 25-200 mg daily used 5
- Higher doses increase side effects 5
- Full effectiveness requires several months 5
Monitoring Parameters
Heart Failure Patients
Check potassium and creatinine at 3 days, 1 week, then monthly for 3 months, then every 3 months 6
- More frequent monitoring with dose changes or clinical instability 1
- Monitor volume status and renal function periodically 7
Acne Patients (Young, Healthy Women)
Routine potassium monitoring NOT required in young healthy women without cardiac/renal disease or interacting medications 5
- Monitor only if risk factors for hyperkalemia present 5
- No monitoring needed with concomitant drospirenone-containing oral contraceptives 5
Primary Aldosteronism
Regular monitoring of potassium and renal function, especially with stage 3 CKD 4
Contraindications
Absolute contraindications per FDA label: 7
- Hyperkalemia
- Addison's disease
- Concomitant use of eplerenone
Clinical contraindications from guidelines:
- Significant renal impairment (eGFR <30 mL/min/1.73 m²) 1
- Baseline serum potassium >5.0 mEq/L 6
- Serum creatinine >2.5 mg/dL in men or >2.0 mg/dL in women 6
- Pregnancy (Category C - risk of feminization of male fetus) 5
Common Adverse Effects
Dose-Dependent Effects
Menstrual irregularities (15-30%) - most common in acne patients 5
- Relative risk 4.12 at 200 mg/day vs lower doses 5
- Minimize with concomitant oral contraceptive or hormonal IUD 5
Gynecomastia in males (dose-dependent) 3
Other Common Effects
- Breast tenderness: 3-5% 5
- Dizziness: 3-4% 5
- Nausea: 2-4% 5
- Headache: 2% 5
- Polyuria: 1-2% 5
- Fatigue: 1-2% 5
Serious Adverse Effects
Hyperkalemia - most dangerous complication 7
- 2-5% in clinical trials 6
- Up to 24-36% in real-world practice 6
- Higher risk with renal insufficiency, heart failure, ACE inhibitors/ARBs 5
Management of hyperkalemia: 2
- K+ 5.5-6.0 mEq/L: Halve dose to 25 mg alternate days
- K+ ≥6.0 mEq/L: Stop immediately, monitor closely, treat hyperkalemia
Worsening renal function 2
- Creatinine >220 μmol/L (2.5 mg/dL): Halve dose
- Creatinine >310 μmol/L (3.5 mg/dL): Stop immediately
Critical Clinical Pitfalls
Avoid Triple Therapy
Do NOT combine ACE inhibitor + ARB + spironolactone 6
- Significantly increases hyperkalemia risk
- Routine triple combination should be avoided 6
Patient Counseling
- Stop spironolactone during diarrhea or dehydration 6
- Avoid high-potassium foods 6
- Avoid NSAIDs 8
- Discontinue or reduce potassium supplements 6
Real-World vs Trial Data
Hyperkalemia occurs more frequently in clinical practice than trials, especially in elderly patients 2
Special Populations
Pregnancy and Lactation
- Pregnancy Category C - avoid due to risk of male fetus feminization 5
- Compatible with breastfeeding - minimal risk to infant 5