Aldactone%252525252525252525252520%252525252525252525252528spironolactone%252525252525252525252529

# Aldactone (spironolactone) ## Overview Spironolactone is a potassium-sparing diuretic and a competitive aldosterone receptor antagonist. It acts primarily in the distal convoluted tubule and collecting duct to inhibit sodium reabsorption and potassium excretion. ## Primary Indications * Heart failure (NYHA Class II–IV, HFrEF) * Edema associated with cirrhosis or nephrotic syndrome * Primary hyperaldosteronism (diagnosis and management) * Essential hypertension * Off-label: Hirsutism, acne, hormonal therapy for gender affirmation. ## Adult Dosing * **Heart Failure (HFrEF):** Start 12.5–25 mg once daily; titrate to target 25 mg daily based on potassium levels and renal function. Maximum: 50 mg/day. * **Edema (Cirrhosis/Nephrosis):** 25–200 mg daily in single or divided doses. * **Hypertension:** 25–100 mg daily in single or divided doses. * **Primary Hyperaldosteronism:** 100–400 mg daily prior to surgery; use lowest effective dose for maintenance. ## Pediatric Dosing * **Heart Failure:** 1–3 mg/kg/day divided once or twice daily. Maximum: 2 mg/kg/dose or 50 mg/day (varies by institutional protocol). * **Edema/Hypertension:** 1–3.3 mg/kg/day divided once or twice daily. Maximum: 200 mg/day (or 3.3 mg/kg/day). ## Dose Adjustments * **Renal Impairment:** If eGFR < 30 mL/min/1.73m², avoid initiation or exercise extreme caution due to high risk of hyperkalemia. * **Hepatic Impairment:** Use with caution; monitor for fluid and electrolyte imbalances frequently. ## Contraindications * Hypersensitivity to spironolactone. * Anuria or acute renal insufficiency. * Significant renal impairment (eGFR < 30 mL/min/1.73m² or serum Cr > 2.5 mg/dL in men/2.0 mg/dL in women). * Addison’s disease. * Concomitant use of eplerenone or potassium supplements. ## Adverse Effects * **Common:** Hyperkalemia, gynecomastia, breast tenderness, cramping, GI disturbance. * **Serious:** Severe hyperkalemia (cardiac arrhythmias), metabolic acidosis, agranulocytosis, Stevens-Johnson syndrome (rare). ## Key Drug Interactions * **Potassium-sparing agents/supplements/salt substitutes:** High risk of lethal hyperkalemia. * **ACE Inhibitors/ARBs/Aliskiren:** Increased risk of hyperkalemia. * **Digoxin:** May decrease renal clearance; monitor for digitalis toxicity. * **Lithium:** May reduce renal clearance, increasing risk of toxicity. * **NSAIDs:** May reduce diuretic efficacy and increase risk of renal impairment. ## Monitoring * **Potassium:** Baseline, within 1 week of initiation/dose change, and then periodically (standard: at least monthly for the first 3 months or as clinically indicated). * **Renal Function:** Baseline BUN/Creatinine/eGFR; assess periodically. * **Blood Pressure:** Monitor for orthostasis, especially in elderly patients. ## Clinical Pearls * **Hyperkalemia Risk:** Greatest in the first 4 weeks of therapy. Patients should be counseled to avoid potassium-rich diets and salt substitutes containing KCl. * **Anti-androgen effects:** Due to its structure, spironolactone can cause menstrual irregularities and decreased libido; this is dose-dependent. * **Timing:** Administer in the morning to prevent nocturia. * **Absorption:** Take consistently with or without food to minimize variability. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical practice and institutional protocols vary. Always verify specific dosing, safety warnings, and drug interactions via current prescribing information (e.g., DailyMed, Lexicomp, or UpToDate) before administering medication.