Spironolactone

Potassium-sparing Diuretic·Cardiovascular - Diuretics

HFrEF, ascites due to cirrhosis, primary hyperaldosteronism, resistant hypertension

PBSMRAAldactone, Spiractin25 mg tabletS4+1

Max Dose

400 mg/day

Half-life

1.4 h (Act: 16h)

Hyperkalemia

HIGH RISK

Gynecomastia

COMMON

Rapid Summary

Overview

Aldosterone antagonist. Provides powerful mortality benefits in heart failure by preventing cardiac fibrosis, and is the drug of choice for cirrhotic ascites.

Maximum Dose

Max 50 mg/day (Heart Failure) • Max 400 mg/day (Ascites).

Clinical Focus

Potassium levels must be meticulously monitored, especially when combined with ACE inhibitors.

Bottom Line

Spironolactone is the cornerstone MRA for heart failure and resistant hypertension with proven mortality benefit, but causes gynaecomastia in males and dangerous hyperkalaemia.

Formulation & Access

Brand Names

Aldactone, Spiractin

Oral Routes

Tablets (25 mg, 100 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

HFrEF, ascites due to cirrhosis, primary hyperaldosteronism, resistant hypertension.

Off-Label

OFF

Hormonal acne, PCOS, hirsutism.

Clinical Place

Fourth pillar of HFrEF management. Gold standard for managing portal hypertension/ascites.

Quick reference

Class & Role

Potassium-sparing Diuretic — Aldosterone antagonist.

Route / Formulation

Tablets (25 mg, 100 mg). (Aldactone, Spiractin)

Usual Dose & Max

PO 12.5–25 mg OD. Target Max 50 mg/day.

Key Indication Doses

Heart Failure (HFrEF): PO 12.5–25 mg OD. Target Max 50 mg/day. Ascites (Hepatic Cirrhosis): Start PO 100 mg OD. May titrate up to Max 400 mg/day (often paired with frusemide in a 100:40 ratio). Resistant Hypertension: PO 12.5-25 mg OD.

Best Uses

Spironolactone is the cornerstone MRA for heart failure and resistant hypertension with proven mortality benefit, but causes gynaecomastia in males and dangerous hyperkalaemia.

Avoid / Cautions

Baseline K+ > 5.0 mmol/L, severe renal impairment (eGFR < 30), Addison's disease. Pregnancy Category B3. Avoid due to potential feminisation of male fetus.

Key Risks

Electrolytes: Hyperkalemia. Hyponatremia. Endocrine: Gynecomastia (breast tissue growth in men), breast pain, menstrual irregularities (due to anti-androgenic effects). Renal: AKI (especially if combined with NSAIDs).

Key Interactions

ACEi, ARBs, potassium supplements (Massive hyperkalemia risk). May increase half-life of Digoxin. Monitor TDM.

Monitoring

Strict U&E monitoring. Check K+ and creatinine at 1 week, 4 weeks, and after any dose changes. Monitor Weight in ascites/HF.

Clinical Pearl

In liver cirrhosis with ascites, Spironolactone and Frusemide are typically prescribed in a 100 mg to 40 mg ratio. This precise balance maintains normokalemia while clearing the fluid.

Access

Aldactone, Spiractin25 mg tablet

Brand: Aldactone, Spiractin
Formulation: Tablets (25 mg, 100 mg)

Spironolactone

Potassium-sparing Diuretic·Cardiovascular - Diuretics

HFrEF, ascites due to cirrhosis, primary hyperaldosteronism, resistant hypertension

PBSMRAAldactone, Spiractin25 mg tabletS4+1

Max Dose

400 mg/day

Half-life

1.4 h (Act: 16h)

Hyperkalemia

HIGH RISK

Gynecomastia

COMMON

Rapid Summary

Overview

Aldosterone antagonist. Provides powerful mortality benefits in heart failure by preventing cardiac fibrosis, and is the drug of choice for cirrhotic ascites.

Maximum Dose

Max 50 mg/day (Heart Failure) • Max 400 mg/day (Ascites).

Clinical Focus

Potassium levels must be meticulously monitored, especially when combined with ACE inhibitors.

Bottom Line

Spironolactone is the cornerstone MRA for heart failure and resistant hypertension with proven mortality benefit, but causes gynaecomastia in males and dangerous hyperkalaemia.

Formulation & Access

Brand Names

Aldactone, Spiractin

Oral Routes

Tablets (25 mg, 100 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

HFrEF, ascites due to cirrhosis, primary hyperaldosteronism, resistant hypertension.

Off-Label

OFF

Hormonal acne, PCOS, hirsutism.

Clinical Place

Fourth pillar of HFrEF management. Gold standard for managing portal hypertension/ascites.

Quick reference

Class & Role

Potassium-sparing Diuretic — Aldosterone antagonist.

Route / Formulation

Tablets (25 mg, 100 mg). (Aldactone, Spiractin)

Usual Dose & Max

PO 12.5–25 mg OD. Target Max 50 mg/day.

Key Indication Doses

Best Uses

Spironolactone is the cornerstone MRA for heart failure and resistant hypertension with proven mortality benefit, but causes gynaecomastia in males and dangerous hyperkalaemia.

Avoid / Cautions

Baseline K+ > 5.0 mmol/L, severe renal impairment (eGFR < 30), Addison's disease. Pregnancy Category B3. Avoid due to potential feminisation of male fetus.

Key Risks

Key Interactions

ACEi, ARBs, potassium supplements (Massive hyperkalemia risk). May increase half-life of Digoxin. Monitor TDM.

Monitoring

Strict U&E monitoring. Check K+ and creatinine at 1 week, 4 weeks, and after any dose changes. Monitor Weight in ascites/HF.

Clinical Pearl

In liver cirrhosis with ascites, Spironolactone and Frusemide are typically prescribed in a 100 mg to 40 mg ratio. This precise balance maintains normokalemia while clearing the fluid.

Access

Aldactone, Spiractin25 mg tablet

Brand: Aldactone, Spiractin
Formulation: Tablets (25 mg, 100 mg)