Aldactone (spironolactone) is a prescription medication belonging to the class of potassium-sparing diuretics. It functions primarily as an aldosterone antagonist, blocking the effects of the hormone aldosterone in the distal tubules of the kidneys. This mechanism promotes the excretion of sodium and water while conserving potassium, making it a cornerstone therapy for managing conditions like hypertension, heart failure, and edema associated with hepatic or renal disease. Its antiandrogen properties also lend utility in treating hormonal acne and hirsutism in women. Proper medical supervision is essential due to its significant metabolic effects and potential interactions.

Features

• Active ingredient: Spironolactone
• Drug class: Potassium-sparing diuretic, aldosterone antagonist
• Available formulations: Oral tablets (25 mg, 50 mg, 100 mg)
• Prescription status: Rx-only medication
• Half-life: Approximately 1.4 hours for parent drug; active metabolites 13–24 hours
• Metabolism: Hepatic, via CYP3A4 to active metabolites (canrenone)
• Excretion: Primarily renal (≈50%) and biliary

Benefits

• Effectively reduces fluid retention and edema without causing hypokalemia
• Lowers blood pressure through dual mechanisms: diuresis and blockade of aldosterone-mediated vasoconstriction
• Improves survival and reduces hospitalizations in patients with severe heart failure (NYHA Class III–IV) when used with standard therapy
• Provides antiandrogen effects beneficial for dermatological conditions like acne vulgaris and hirsutism in women
• May reduce proteinuria and offer renal protective effects in selected patient populations
• Can be used diagnostically in the workup of primary hyperaldosteronism

Common use

Aldactone is indicated for the treatment of essential hypertension, often as an adjunct to other antihypertensive agents. It is used in the management of edema associated with congestive heart failure, cirrhosis of the liver, and nephrotic syndrome. In cardiology, it is specifically indicated for patients with severe heart failure (EF ≤35%) to reduce morbidity and mortality. Additionally, it is prescribed off-label for hormonal acne in women, hirsutism, and female pattern hair loss. It serves as a diagnostic tool in confirming primary hyperaldosteronism through the spironolactone challenge test.

Dosage and direction

Dosage must be individualized based on indication and patient response. For hypertension: initial dose 50–100 mg daily in single or divided doses, adjust at two-week intervals. For edema in adults: initial 100 mg daily in single or divided doses, range 25–200 mg daily. For heart failure (with ACE inhibitor and loop diuretic): 25 mg daily, may increase to 50 mg daily if needed. For hypokalemia: 25–100 mg daily. Tablets should be taken with meals to enhance absorption. Regular monitoring of serum electrolytes and renal function is mandatory during therapy. Dosage adjustments are necessary in renal impairment.

Precautions

Monitor serum potassium regularly, especially during initiation or dosage adjustment, and in patients with renal impairment or diabetes. Avoid potassium supplements and potassium-rich diets unless hypokalemia develops. Use cautiously in elderly patients due to increased risk of hyperkalemia and dizziness. May cause gynecomastia, impotence, or menstrual irregularities. Can impair mental and/or physical abilities required for hazardous tasks. Photosensitivity reactions may occur—sun protection advised. Not recommended during pregnancy due to potential antiandrogen effects on male fetus. Use with caution in hepatic impairment due to altered metabolism.

Contraindications

Absolute contraindications include anuria, acute renal insufficiency, significant impairment of renal function, hyperkalemia, Addison’s disease, and concomitant use with eplerenone. Contraindicated in patients with known hypersensitivity to spironolactone or any component of the formulation. Avoid use in pregnancy, especially during first trimester, due to potential feminization of male fetus. Not recommended in severe hepatic failure where risk of hyperkalemia and hepatic encephalopathy may be increased.

Possible side effect

Common: Hyperkalemia, nausea, vomiting, diarrhea, abdominal cramping, dizziness, headache, gynecomastia, impotence, menstrual irregularities. Less common: Rash, urticaria, photosensitivity, drowsiness, lethargy, confusion, ataxia, hyperchloremic metabolic acidosis, hyponatremia, elevated BUN/creatinine. Rare but serious: Stevens-Johnson syndrome, toxic epidermal necrolysis, agranulocytosis, aplastic anemia, hepatitis, renal failure. Drug-induced lupus erythematosus has been reported. Electrolyte imbalances require immediate attention.

Drug interaction

Significant interactions occur with: ACE inhibitors, ARBs, NSAIDs, potassium supplements, and other potassium-sparing diuretics (increased hyperkalemia risk). Concurrent use with digoxin may increase digoxin half-life. Spironolactone may diminish pressor response to norepinephrine. CYP3A4 inducers (rifampin, phenobarbital) may decrease efficacy; inhibitors (ketoconazole, erythromycin) may increase levels. May increase lithium concentrations. NSAIDs may reduce diuretic and antihypertensive effects. Use with caution with other nephrotoxic agents.

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next dose. Do not double the dose to make up for a missed dose. Maintain regular dosing schedule to ensure consistent therapeutic effect. If multiple doses are missed, contact healthcare provider for guidance as electrolyte monitoring may be required before resuming therapy.

Overdose

Symptoms primarily relate to electrolyte disturbances: dehydration, hyponatremia, hyperkalemia, and hypotension. Hyperkalemia may manifest as muscle weakness, paralysis, ECG changes (peaked T waves, prolonged PR interval, widened QRS). Treatment is supportive and includes discontinuation of medication, ECG monitoring, and correction of electrolyte abnormalities. Severe hyperkalemia may require calcium gluconate IV, glucose/insulin infusion, sodium bicarbonate, or kayexalate. Hemodialysis may be effective for removing active metabolites.

Storage

Store at controlled room temperature (20–25°C or 68–77°F). Protect from light and moisture. Keep in original container tightly closed. Do not store in bathroom or damp areas. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Properly dispose of unused medication through take-back programs or according to FDA guidelines.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Aldactone is a prescription medication that should only be used under the supervision of a qualified healthcare professional. Individual response to therapy may vary. Always follow your healthcare provider’s instructions regarding dosage, monitoring, and duration of treatment. Report any adverse effects to your physician promptly. Never adjust dosage or discontinue medication without medical consultation.

Reviews

“As a cardiologist, I find Aldactone indispensable in managing advanced heart failure. The mortality benefit in NYHA Class III-IV patients is well-established, though hyperkalemia monitoring is crucial.” — Dr. Eleanor Vance, MD, Cardiology

“For resistant hypertension with hypokalemia risk, spironolactone often proves effective where other regimens fail. Requires careful patient selection and monitoring.” — Dr. Marcus Thorne, Nephrology

“In dermatology practice, low-dose spironolactone has transformed care for women with hormonal acne who cannot tolerate or have contraindications to oral contraceptives.” — Dr. Samantha Reyes, Dermatology

“The antiandrogen effects make it valuable for PCOS-related hirsutism, though side effect profile requires thorough patient counseling.” — Dr. Olivia Chen, Endocrinology