Drug reference

Spironolactone

Potassium-Sparing Diuretic · Antihypertensive

Also known as Aldactone, Spiractin, Spironol, Canrenone (active metabolite)

START

12.5-25 mg PO once daily (HF) · 50-100 mg/day (HTN, ascites)

TYPICAL MAX

400 mg/day (cirrhosis ascites)

STOP IF

Hyperkalemia (>5.5) · severe CKD · Addison's · anuria

WATCH

K⁺ + Cr at 1 week then monthly · gynecomastia

CDSCO approvedJan AushadhiATC C03DA01

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 1d · natriuretic effect (1-2 days)
PEAK: 3d · max diuretic effect (3 days)
t½: 16h · active metabolite canrenone t½
DURATION: 2d · post-stop effect (slow off)

EXCRETION

Hepatic CYP3A4 to canrenone · renal/biliary metabolites

route + CYP

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

Category C — antiandrogenic risk, avoid

FDA category + note

Top interactionssee all 12 →

PotassiumContraindicatedDatabaseDDInter
DigoxinSevereTextbook-citedKDT 7e · p949
LithiumSevereTextbook-citedKDT 7e · p949
ImidaprilSevereTextbookKDT 7e

Available in India

20 branded formulations and 83 fixed-dose combinations. Look up specific brands in the Drugs workspace.

Jan Aushadhi — generic available at GoI pharmacies

Mechanism

Spironolactone acts as a competitive antagonist of aldosterone at mineralocorticoid receptors primarily in the distal renal tubules and collecting ducts. This blockade inhibits aldosterone's effects, leading to increased excretion of sodium and water, while conserving potassium and hydrogen ions. It also possesses antiandrogenic activity by inhibiting androgen synthesis and binding to androgen receptors.

Indications

Heart failure (NYHA Class III-IV)Hypertension (especially resistant hypertension)Edema associated with heart failureEdema associated with cirrhosis (with ascites)Edema associated with nephrotic syndromePrimary hyperaldosteronism (Conn's syndrome)Hypokalemia (prevention/treatment)Hirsutism (off-label)Acne (off-label)Polycystic Ovary Syndrome (PCOS) (off-label)edema (coadministered with thiazide or loop diuretics)hypertension (coadministered with thiazide or loop diuretics)primary hyperaldosteronismrefractory edema associated with secondary aldosteronism (cardiac failure, hepatic cirrhosis, nephrotic syndrome, severe ascites)hepatic cirrhosis (diuretic of choice)heart failure with reduced ejection fraction (as adjunct to standard therapy)proteinuria in chronic kidney diseaseheart failurehypertensionhyperaldosteronismhypokalemiaasciteshirsutism (blocking androgen action)antiandrogen in male-to-female gender transitionResistant hypertensionadd-on therapy to ACE inhibitors + other drugs in moderate-to-severe CHFretard disease progression in CHFreduce episodes of decompensation and death due to heart failurereduce sudden cardiac deathshelp restoration of diuretic response to furosemide when refractoriness has developedTo counteract K+ loss due to thiazide and loop diureticsEdema (cirrhotic and nephrotic edema, refractory edema)Hypertension (as adjuvant to thiazide, attenuate renal fibrosis and ventricular/vascular hypertrophy)Moderate to severe CHF (retard disease progression, lower mortality)Long-term mineralocorticoid receptor inhibition for STEMI patients already receiving therapeutic ACE inhibitor doses, with LV ejection fraction ≤40%, and either symptomatic HF or diabetes mellitus.

Dosing

Adult: Heart Failure: Initial 12.5-25 mg PO daily, titrate up to 50 mg daily based on patient response and potassium levels. Hypertension: Initial 25-50 mg PO daily, may be increased up to 100 mg daily. Edema (cirrhosis/ascites): Initial 50-100 mg PO daily, can be gradually increased up to 400 mg/day, often with a loop diuretic.…
Pediatric: Edema/Hypertension: Initial 1-3 mg/kg/day PO in 1-2 divided doses. Maximum 100 mg/day.
Renal adjustment: CrCl 30-50 mL/min: Consider starting at lower doses (e.g., 12.5 mg every other day or 12.5 mg daily) and monitor potassium and renal function closely. CrCl <30 mL/min or serum creatinine >2 mg/dL: Contraindicated due to high risk of severe hyperkalemia.
Hepatic adjustment: Use with caution in severe hepatic impairment, as it may exacerbate hepatic encephalopathy. No specific dose adjustment guidelines, but consider lower starting doses and vigilant monitoring.
Geriatric: Start with lower doses (e.g., 12.5 mg daily) due to increased risk of hyperkalemia and age-related decline in renal function. Monitor serum potassium and renal function closely.
Max dose: For heart failure, typically 50 mg/day. For hypertension, typically 100 mg/day. For severe edema/hyperaldosteronism, up to 400 mg/day.

Pharmacokinetics

Onset

Diuretic effect: 2-3 days. Antihypertensive effect: 2-3 weeks. Aldosterone antagonism: 24-48 hours.

Peak effect

Peak plasma concentration for spironolactone: 1-2 hours. For active metabolites (e.g., canrenone): 2-4 hours.

Duration

Diuretic effects persist for 2-3 days due to active metabolites.

Half-life

Spironolactone: 1.3 hours. Canrenone (active metabolite): 13-24 hours.

Bioavailability

60-90% (variable, increased with food)

Protein binding

Spironolactone: >90%. Canrenone: >95%.

Metabolism

Rapidly and extensively metabolized in the liver to active metabolites including canrenone, 7-alpha-thiomethylspironolactone, and 6-beta-hydroxy-7-alpha-thiomethylspironolactone.

Excretion

Primarily renal (metabolites) and biliary/fecal.

Contraindications

Hyperkalemia (serum potassium >5.0 mEq/L)
Addison's disease
Anuria
Acute renal insufficiency
Significant renal impairment (e.g., CrCl <30 mL/min or serum creatinine >2 mg/dL)
Concomitant use with eplerenone or other potassium-sparing diuretics
Known hypersensitivity to spironolactone or any component
hyperkalemia
patients at increased risk of developing hyperkalemia (e.g., renal failure)
peptic ulcers
renal insufficiency with creatinine clearance <30 mL/min
combination with other K+-sparing diuretics
pregnancy (for hirsutism, due to potential impaired virilization of male fetus)
Serum creatinine >2.5 mg/dL in men
Serum creatinine >2.0 mg/dL in women
renal insufficiency
Peptic ulcer
K+ supplements
Toxaemia of pregnancy
Significant renal dysfunction (creatinine ≥2.5 mg/dL in men and ≥2.0 mg/dL in women)
Hyperkalemia (potassium ≥5.0 mEq/L)

Side effects

Common

GynecomastiaBreast pain/tendernessHyperkalemiaNauseaVomitingDiarrheaAbdominal crampsHeadacheDizzinessFatigueMenstrual irregularitiesPost-menopausal bleedingImpotenceDecreased libidogastritisgastric bleedingdrowsinesslethargyataxiaconfusionskin rashesgynecomastia (10% of men)dysmenorrhea (in women)Erectile dysfunction (in men)Gynecomastia (in men)Benign prostatic hyperplasia (in men)gynaecomastiaMental confusionEpigastric distressLoose motionsBreast tendernessErectile dysfunctionLoss of libidohyponatremiapainful gynecomastiaHyperkalemia, especially in CKD and with potassium-sparing agentsTender breastsErectile dysfunction in men

Serious

Severe hyperkalemia (potentially fatal)
Acute renal failure
Hyponatremia
Metabolic acidosis
Agranulocytosis
Leukopenia
Thrombocytopenia
Steven-Johnson Syndrome (SJS)
Toxic Epidermal Necrolysis (TEN)
Drug reaction with eosinophilia and systemic symptoms (DRESS)
Gastrointestinal bleeding
Gastric ulceration
hyperkalemia
metabolic acidosis (in cirrhotic patients)
peptic ulcers
Stevens-Johnson syndrome
toxic epidermal necrolysis
drug rash with eosinophilia and systemic symptoms (DRESS)
blood dyscrasias
Hyperkalaemia (especially if renal function inadequate)
Acidosis (especially in cirrhotics)

Pregnancy & lactation

Pregnancy

Category C — antiandrogenic risk, avoid

Lactation

Spironolactone metabolites are excreted in breast milk. Due to the potential for serious adverse effects on the infant, including electrolyte disturbances and antiandrogenic effects, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother. Generally not recommended during breastfeeding.