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MEDICINE MONOGRAPH CODE: [3.15] ID: TIP-MED-000015

Spironolactone

Active Ingredient / Scientific Identity: Spironolactone • Class: Potassium-Sparing Diuretic; Mineralocorticoid (Aldosterone) Receptor Antagonist (MRA)

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THE INDIAN PHARMACIST — Educational Reference Sheet
Profile: Spironolactone ([3.15] | ID: TIP-MED-000015) • Last Reviewed: 2026-11-10
Source URL: https://theindianpharmacist.com/medicine/3-15-spironolactone/
Generic / Entity NameSpironolactone ([3.15])
Verified Indian Brands / RefArkamin (Unichem), Catapres (Boehringer)
Pharmacological ClassPotassium-Sparing Diuretic; Mineralocorticoid (Aldosterone) Receptor Antagonist (MRA)
Available Dosage FormsOral Film-Coated Tablets: 25 mg, 50 mg, 100 mg
Regulatory ClassificationSchedule H Prescription Drug • NLEM 2022 Core Essential Medicine
Key Warning & Review DateDrug of choice in cirrhotic ascites (hyperaldosteronism state); monitor electrolytes to prevent hepatic encephalopathy.
Reviewed: 2026-11-10
Safety Matrix:⚖️ Legal Status: Schedule H Prescription Drug • NLEM 2022 Core Essent✔️ Standard Clinical Dispensing Precautions

1. Clinical & Scientific Overview

Spironolactone (TIP-MED-000015, Reference Code [3.15]) is classified under Cardiovascular & Antithrombotic Medicines (Ch 03) as a Potassium-Sparing Diuretic; Mineralocorticoid (Aldosterone) Receptor Antagonist (MRA). Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug • NLEM 2022 Core Essential Medicine.

Verified Indian Market Examples / Compendial Status:
Arkamin (Unichem), Catapres (Boehringer)
Representative Indian Market Examples (Edition 2.7 Ch 03 [3.15], p. 28): Aldactone (RPG Life Sciences), Spironolactone in Lasilactone (Sanofi) and Dytor Plus (Cipla) — Strengths & Forms: Oral Film-Coated Tablets: 25 mg, 50 mg, 100 mg
Dosage Forms & Available Strengths:
Oral Film-Coated Tablets: 25 mg, 50 mg, 100 mg
Routes: Oral / Parenteral / Topical as specified by formulation

3. Mechanism of Action & Pharmacodynamics

Competitively binds cytoplasmic Mineralocorticoid Receptors (MR) in the principal cells of the late distal convoluted tubule and cortical collecting duct (working from the basolateral blood side, independent of luminal filtration). Blocks aldosterone-induced transcription of luminal Epithelial Sodium Channels (ENaC) and basolateral Na+/K+-ATPase pumps, promoting mild natriuresis (2%–3% of filtered Na+) while conserving K+ and H+ and preventing aldosterone-mediated myocardial fibrosis and ventricular remodelling.

4. Therapeutic Indications & Evidence-Supported Uses

  • HFrEF (Heart Failure with Reduced Ejection Fraction, NYHA II–IV, LVEF <=35% — RALES trial 30% mortality reduction)
  • Ascites and oedema secondary to hepatic cirrhosis (diuretic of first choice, alone or in 100:40 ratio with Furosemide)
  • Resistant hypertension (4th-line add-on — PATHWAY-2 trial) and Primary Hyperaldosteronism (Conn's syndrome)

🇮🇳 Jurisdiction & Indication Note: Indications and schedules reflect Indian compendial and regulatory records (CDSCO / Indian Pharmacopoeia & NFI / NLEM 2022). Where international reference labels (US FDA DailyMed / NCBI StatPearls) are cited for pharmacokinetic or mechanistic parameters, international approvals do not automatically imply CDSCO approval in India.

5. Educational Dosage Context, Formulations & Administration

Educational Dosing & Regimen Summary: HFrEF / Resistant Hypertension: 25 mg orally once daily (may increase to 50 mg once daily if serum K+ <=5.0 mEq/L). Cirrhotic Ascites: 100 mg/day (titrated up to 400 mg/day in a 100 mg Spironolactone : 40 mg Furosemide ratio).

Administration & Meal Timing: Oral; take once daily with breakfast or lunch.

6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment

Absorption & Disposition:
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Metabolism & Biotransformation:
Drug of choice in cirrhotic ascites (hyperaldosteronism state); monitor electrolytes to prevent hepatic encephalopathy.
Elimination & Renal Adjustment:
CONTRAINDICATED if eGFR < 30 mL/min, serum creatinine > 2.5 mg/dL (men) or > 2.0 mg/dL (women), or baseline serum K+ > 5.0 mEq/L.
Hepatic Impairment Considerations:
Drug of choice in cirrhotic ascites (hyperaldosteronism state); monitor electrolytes to prevent hepatic encephalopathy.

7. Contraindications, Precautions & High-Risk Warnings

Contraindications & Red-Flag Precautions:
  • Hyperkalaemia (serum K+ > 5.0 mEq/L) or Addison's disease
  • Severe renal insufficiency (eGFR < 30 mL/min) or anuria
  • Concomitant Eplerenone or routine potassium supplements

Key Clinical Precautions: Drug of choice in cirrhotic ascites (hyperaldosteronism state); monitor electrolytes to prevent hepatic encephalopathy.

8. Adverse Effects Profile

Common & Mechanism-Related Adverse Effects:
  • Hyperkalaemia (risk of peaked T waves, sine-wave QRS, and fatal cardiac arrest if K+ not monitored when combined with ACEi/ARBs)
  • Endocrine anti-androgenic and progestogenic cross-reactivity: painful gynaecomastia and impotence in men (10% dose-dependent; switch to selective Eplerenone if this occurs), menstrual irregularities/breast tenderness in women
  • Hyperchloraemic normal-anion-gap metabolic acidosis
Serious / Dose-Limiting Adverse Effects:
  • Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.

9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions

  • ACE Inhibitors, ARBs (Telmisartan), Aliskiren, Trimethoprim-Sulfamethoxazole, NSAIDs, Heparin, & K+ supplements / salt substitutes: life-threatening hyperkalaemia (check K+ and Cr at 1 week, 4 weeks, and periodically)
  • Digoxin: Spironolactone reduces renal tubular clearance of Digoxin and its metabolites cross-react with older Digoxin immunoassays
  • Aspirin (high-dose): inhibits tubular secretion of canrenone and blunts natriuretic efficacy

10. Clinical Monitoring, Patient Counselling & Storage

Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

Pharmacist Patient Counselling Points:

  • Take with food. Avoid high-potassium salt substitutes (LoSalt) and excessive potassium supplements unless instructed after a blood test.
  • Attend scheduled blood tests for serum potassium and kidney function 1 week and 4 weeks after starting or increasing the dose.
  • Men experiencing breast tenderness or enlargement (gynaecomastia) should consult their physician, as selective Eplerenone can be substituted.

Storage, Stability & Dispensing Safeguards: Store below 30°C protected from light.

11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)

THE 12-STEP ORAL DRUG JOURNEY THROUGH THE HUMAN BODY (LADME) Note: IV bolus enters Step 6 directly (F = 100%); Sublingual & Transdermal routes bypass Step 4–5 Portal First-Pass Metabolism 1. Oral Administration • Tablet / Capsule swallowed • Gastric emptying to duodenum pH 1.5–3.5 (Stomach) 2. Disintegration & Dissolution • Tablet breaks into granules • API dissolves in GI fluid Noyes-Whitney Dissolution Rate 3. GI Epithelial Absorption • Crosses intestinal villi • Passive / Active / P-gp efflux Small Intestine (Large Surface Area) 4. Portal Circulation • Mesenteric veins → Portal vein • Delivers blood to liver sinusoids Pre-systemic Venous Conduit 5. First-Pass Metabolism • Gut & hepatic CYP450 extraction • High: GTN, Propranolol, Morphine Determines Bioavailability (F = f_a × (1-E_H)) 6. Systemic Circulation • Hepatic vein → IVC → Heart • Unbound vs Albumin-bound drug Only FREE drug is active 7–8. Tissue Distribution (Vd) • Capillary permeation to organs • Blood-Brain & Placental barriers Vd = Dose / C_0 (L or L/kg) 9. Target Site of Action • Receptors (GPCR, Ion channel) • Enzymes & Carrier Transporters Pharmacodynamic Effect (E_max, EC50) 10. Hepatic Biotransformation • Phase I (CYP450 Oxidation/Hydrolysis) • Phase II (Glucuronidation/Sulfation) Converts lipophilic drug → hydrophilic metabolite 11. Renal & Biliary Elimination • Nephron: Filtration + Secretion − Reabsorption • Biliary excretion & Enterohepatic recycling Total Clearance CL_tot = CL_renal + CL_hepatic 12. Excretion from the Body • Urine (Primary polar metabolite route) • Bile/Faeces, Expired Air, Sweat, Milk Elimination Half-Life t1/2 = (0.693 × Vd) / CL
svg-v339-01-adme-12-step-journey — 8.1 Complete 12-Step Journey of an Orally Administered Drug (ADME): Figure 8.1: The 12-step physiological journey of a typical orally administered solid dosage form through Liberation, Absorption, Distribution, Metabolism, and Excretion (LADME). Note: Parenteral (IV), sublingual, and inhalational routes bypass gastrointestinal absorption and/or hepatic first-pass metabolism.

12. Authoritative References, Regulatory Sources & Editorial Disclaimer

Primary Compendial & Guideline Reference: Indian Pharmacopoeia (IP 2026) • NLEM 2022 (MoHFW) • CDSCO Approved Prescribing Information

Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)

Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: VERIFIED_EDUCATIONAL_CONTENT

Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.

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Educational Reference Notice: This printout from THE INDIAN PHARMACIST (https://theindianpharmacist.com/medicine/3-15-spironolactone/, Last Reviewed: 2026-11-10) is an educational reference sheet for students and healthcare learners. It is NOT an official prescribing guideline or patient-specific treatment order.