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# Aldactone (spironolactone)
## Overview
Potassium-sparing diuretic and aldosterone antagonist. Structurally similar to corticosteroids, with antiandrogenic and progestational effects.
## Primary Indications
- Heart failure (NYHA class III–IV, with reduced ejection fraction)
- Resistant hypertension (as add-on therapy)
- Primary hyperaldosteronism (diagnosis and treatment)
- Edema due to cirrhosis, nephrotic syndrome, or heart failure
- Acne vulgaris and hirsutism (off-label in females)
## Adult Dosing
- **Heart failure**: 12.5–25 mg once daily; max 50 mg/day
- **Hypertension**: 25–50 mg once daily; max 100 mg/day (often in divided doses)
- **Primary hyperaldosteronism**: 100–400 mg/day in divided doses
- **Edema**: 25–200 mg/day in 1–2 divided doses
## Pediatric Dosing
- **Edema/hypertension**: Initial 1 mg/kg/day (max 3.3 mg/kg/day) in 1–2 divided doses; max 100 mg/day
- **Heart failure**: 1 mg/kg once daily (max 3 mg/kg/day, usual max 50 mg/day); use only if eGFR >30 mL/min/1.73m²
- Exact dosing depends on local protocol for specific indications
## Dose Adjustments
- **Renal impairment**: CrCl 30–50: reduce dose; CrCl <30: contraindicated (risk of hyperkalemia)
- **Hepatic impairment**: Use with caution; no specific dose reduction established but monitor closely
- **Elderly**: Start at low end of dosing range (12.5–25 mg/day)
## Contraindications
- Anuria, acute or chronic renal insufficiency (CrCl <30)
- Hyperkalemia (serum K⁺ >5.5 mEq/L)
- Addison’s disease
- Concomitant use with eplerenone or other potassium-sparing diuretics
## Adverse Effects
- Hyperkalemia (dose-related; highest risk with renal impairment, ACEi/ARB use)
- Gynecomastia, breast tenderness (dose-related; reversible)
- Menstrual irregularities, impotence, hirsutism reduction
- Gastrointestinal upset, drowsiness, ataxia (less common)
- Increased risk of gastrointestinal bleeding (especially with NSAIDs)
## Key Drug Interactions
- **ACE inhibitors/ARBs**: Additive hyperkalemia risk
- **Potassium supplements, salt substitutes**: Avoid unless hypokalemia documented
- **Digoxin**: Can increase digoxin levels (monitor)
- **NSAIDs**: Reduced diuretic effect, increased potassium
- **Lithium**: Increased lithium toxicity risk
- **CYP3A4 inhibitors/inducers**: Affect metabolism (clinically minor)
## Monitoring
- Serum potassium and creatinine: baseline, within 1 week of starting/increasing dose, then periodically (more frequently if risk factors)
- Blood pressure, weight, volume status
- Heart failure: monitor for signs of worsening renal function or hyperkalemia
## Clinical Pearls
- Take with food to improve absorption
- Onset of action is slow (2–4 days); full effect may take 2 weeks
- For heart failure, add only after optimizing ACEi/ARB and beta-blocker; ensure baseline K⁺ <5.0 mEq/L and CrCl >30
- Gynecomastia is dose- and duration-dependent; consider eplerenone if problematic
- Spironolactone can interfere with cortisol and androgen assays
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*Educational disclaimer: This information is for educational purposes and does not replace professional judgment. Always verify current prescribing information, local protocols, and the most recent product monograph before making clinical decisions.*
