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# Aldactone (spironolactone)
## Overview
Spironolactone is a potassium-sparing diuretic and an aldosterone antagonist.
## Primary Indications
* Heart failure (NYHA Class II-IV) with reduced ejection fraction
* Edema associated with cirrhosis
* Edema associated with nephrotic syndrome
* Essential hypertension (adjunctive therapy)
* Primary hyperaldosteronism
## Adult Dosing
* **Heart Failure:** Initiate at 25 mg once daily. May titrate to 50 mg once daily within 4 weeks. If needed and tolerated, may further increase to a maximum of 100 mg once daily.
* **Cirrhosis (with edema/ascites):** Initiate at 100 mg once daily. May adjust dose based on response and tolerance, typically between 25 mg and 400 mg daily in divided doses.
* **Nephrotic Syndrome:** Typically 25 mg to 200 mg daily in divided doses. Dosing is highly individualized.
* **Essential Hypertension:** Initiate at 25 mg to 100 mg once daily, in combination with other antihypertensives. May be adjusted to achieve target blood pressure. Maximum dose is generally 400 mg daily.
* **Primary Hyperaldosteronism:** Preoperative: 100 mg to 400 mg daily in divided doses. Postoperative: individualized.
## Pediatric Dosing
Dosing in pediatric patients is variable and depends on the indication and patient weight. Exact dosing often requires consultation with a pediatric specialist or adherence to local protocols. A common starting dose for edema or hypertension may be 1 mg/kg/day divided every 12-24 hours, with a maximum of 3.3 mg/kg/day or 100 mg/day, whichever is less.
## Dose Adjustments
* **Renal Impairment:** Use with caution. May require dose reduction or discontinuation in severe renal impairment. See Contraindications.
* **Hepatic Impairment:** Use with caution. May require dose reduction. See Contraindications.
* **Electrolyte Imbalances:** Dose adjustment or discontinuation may be necessary based on potassium levels.
## Contraindications
* Hyperkalemia (serum potassium >5.5 mEq/L)
* Addison's disease
* Concomitant use with eplerenone
* Anuria
* Serious or progressive renal impairment (CrCl <30 mL/min or serum creatinine >2.5 mg/dL)
* Hypersensitivity to spironolactone or any component of the formulation
## Adverse Effects
* **Common:** Hyperkalemia, hyponatremia, fatigue, headache, dizziness, gastrointestinal upset, gynecomastia, menstrual irregularities.
* **Less Common/Serious:** Hypotension, dehydration, renal dysfunction, Stevens-Johnson syndrome, toxic epidermal necrolysis, rash, fever, confusion.
## Key Drug Interactions
* **ACE inhibitors, ARBs, other potassium-sparing diuretics, potassium supplements, NSAIDs, heparin, trimethoprim/sulfamethoxazole:** Increased risk of hyperkalemia. Monitor potassium closely.
* **Digoxin:** Spironolactone may increase digoxin levels, increasing the risk of toxicity.
* **Lithium:** Spironolactone may decrease lithium clearance, increasing lithium levels.
* **Norepinephrine:** Spironolactone may reduce the vascular responsiveness to norepinephrine.
## Monitoring
* **Serum potassium:** Frequently, especially at initiation, dose changes, or in patients with risk factors for hyperkalemia.
* **Renal function (serum creatinine, BUN):** Frequently.
* **Blood pressure:** Regularly.
* **Electrolytes (sodium):** As clinically indicated.
* **Signs and symptoms of hyperkalemia, hyponatremia, and fluid/electrolyte imbalance.**
## Clinical Pearls
* Spironolactone's anti-androgenic effects can cause gynecomastia in men and menstrual irregularities in women.
* Diuresis may be delayed for several days.
* Avoid concurrent use with other potassium-sparing diuretics or high-dose potassium supplements unless specific indication and close monitoring are in place.
* May cause drowsiness; caution patients regarding driving or operating machinery.
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*Disclaimer: This information is intended for educational purposes and does not substitute for professional medical advice. Always consult the most current prescribing information and your healthcare provider for any medical decisions.*
