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# Aldactone (spironolactone) ## Overview Spironolactone is a potassium-sparing diuretic and a competitive aldosterone receptor antagonist. It acts primarily in the distal renal tubules to increase sodium/water excretion while conserving potassium. ## Primary Indications * Heart failure (NYHA Class II–IV with reduced ejection fraction) * Edematous conditions (cirrhosis, nephrotic syndrome) * Essential hypertension * Primary hyperaldosteronism (diagnostic and treatment) ## Adult Dosing * **Heart failure:** Start 12.5–25 mg once daily. Target dose 25 mg daily based on potassium levels and tolerance. * **Hypertension:** 25–100 mg daily in single or divided doses. * **Edema (Cirrhosis/Nephrotic Syndrome):** 100 mg daily; titration range 25–200 mg daily. * **Primary hyperaldosteronism:** 100–400 mg daily prior to surgery; use lowest effective dose for long-term maintenance. ## Pediatric Dosing * **Heart failure:** 1–3 mg/kg/day divided once or twice daily. * **Hypertension/Diuretic:** 1–3.3 mg/kg/day divided once or twice daily (Max: 200 mg/day). * *Note: Dosing is highly dependent on institutional protocols; verify via pediatric references (e.g., Harriet Lane).* ## Dose Adjustments * **Renal Impairment:** Avoid or use with extreme caution if eGFR <30 mL/min/1.73m². Contraindicated in acute renal insufficiency or anuria. * **Hepatic Impairment:** Adjust dose cautiously in cirrhosis; monitor for fluid/electrolyte imbalances that may precipitate hepatic encephalopathy. ## Contraindications * Hypersensitivity to spironolactone. * Hyperkalemia (>5.0–5.5 mEq/L). * Addison’s disease. * Concomitant use of eplerenone or potassium supplements. * Anuria or acute renal failure. ## Adverse Effects * **Common:** Hyperkalemia, gynecomastia (dose-dependent), breast tenderness, menstrual irregularities, erectile dysfunction. * **Serious:** Severe hyperkalemia (risk of cardiac arrhythmias), hyponatremia, metabolic acidosis, gastrointestinal hemorrhage. ## Key Drug Interactions * **Potassium-elevating agents:** ACE inhibitors, ARBs, NSAIDs, aliskiren, and potassium supplements significantly increase risk of life-threatening hyperkalemia. * **Digoxin:** May decrease clearance and increase plasma levels; monitor for toxicity. * **Lithium:** May reduce renal clearance and increase lithium toxicity risk. ## Monitoring * **Serum Potassium:** Check baseline, 1 week after initiation, 1 week after dose adjustment, and at least monthly for the first 3 months. * **Renal Function (SCr/eGFR):** Monitor at the same intervals as potassium to detect worsening renal function. * **Blood Pressure/Volume Status:** Evaluate for clinical improvement or dehydration. ## Clinical Pearls * **Monitoring frequency:** Once patients are stable on a dose, potassium and renal function monitoring can typically be conducted q3–6 months. * **Anti-androgen effects:** Gynecomastia is more common with higher, long-term doses. It is often reversible upon discontinuation. * **Administration:** May be taken with or without food, but consistency is recommended to reach steady-state absorption. *** *Disclaimer: This information is for educational purposes only. Always consult current, evidence-based clinical databases (e.g., Lexicomp, Clinical Pharmacology) and institutional prescribing guidelines before administering medication.*