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MEDICINE MONOGRAPH CODE: [7.16] ID: TIP-MED-000118

Mefenamic Acid

Active Ingredient / Scientific Identity: Mefenamic Acid • Class: Anthranilic Acid (Fenamate) COX-1 / COX-2 Inhibitor & Prostaglandin Receptor Antagonist (Schedule H)

⚖️ Compare Profile
Generic / Entity NameMefenamic Acid ([7.16])
Verified Indian Brands / RefGeneric Compendial Entry (No Commercial Brand Claimed)
Pharmacological ClassAnthranilic Acid (Fenamate) COX-1 / COX-2 Inhibitor & Prostaglandin Receptor Antagonist (S
Available Dosage FormsTablets: 250 mg, 500 mg; Paediatric Suspension: 100 mg/5 mL
Regulatory ClassificationSchedule H Prescription Drug (To be sold by retail on the prescription of a Registere
Key Warning & Review DateRenal: Contraindicated if eGFR <30–45 mL/min or in dehydrated febrile children. Hepatic: Avoid in active liver disease
Reviewed: 2026-11-10
Safety Matrix:⚖️ Legal Status: Schedule H Prescription Drug (To be sold by retail o✔️ Standard Clinical Dispensing Precautions

1. Clinical & Scientific Overview

Mefenamic Acid (TIP-MED-000118, Reference Code [7.16]) is classified under Pain, Inflammation, Rheumatology & Gout Medicines (Ch 07) as a Anthranilic Acid (Fenamate) COX-1 / COX-2 Inhibitor & Prostaglandin Receptor Antagonist (Schedule H). Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug (To be sold by retail on the prescription of a Registered Medical Practitioner only — Drugs Rules 1945).

Verified Indian Market Examples / Compendial Status:
Representative Indian Market Examples (Edition 2.7 Ch 07 [7.16], p. 86): Meftal-250 / Meftal-500 / Meftal-P (Blue Cross), Ponstan (Pfizer); FDCs: Meftal-Spas (+ Dicyclomine 10 mg), Trapic-MF (+ Tranexamic Acid 500 mg) — Strengths & Dosage Forms: Tablets: 250 mg, 500 mg; Paediatric Suspension: 100 mg/5 mL
Representative Indian Market Examples (Edition 2.7 Ch 07 [7.16], p. 86): Meftal-250 / Meftal-500 / Meftal-P (Blue Cross), Ponstan (Pfizer); FDCs: Meftal-Spas (+ Dicyclomine 10 mg), Trapic-MF (+ Tranexamic Acid 500 mg) — Strengths & Dosage Forms: Tablets: 250 mg, 500 mg; Paediatric Suspension: 100 mg/5 mL
Dosage Forms & Available Strengths:
Tablets: 250 mg, 500 mg; Paediatric Suspension: 100 mg/5 mL
Routes: Oral / Parenteral / Topical as specified by formulation

3. Mechanism of Action & Pharmacodynamics

Anthranilic Acid (Fenamate) COX-1 / COX-2 Inhibitor & Prostaglandin Receptor Antagonist (Schedule H) acting on target receptor/enzyme pathways in Pain, Inflammation, Rheumatology & Gout Medicines (Ch 07): clinical efficacy is mediated via Anthranilic Acid (Fenamate) COX-1 / COX-2 Inhibitor & Prostaglandin Receptor Antagonist (Schedule H) for Primary dysmenorrhoea (uniquely blocks both prostaglandin synthesis AND uterine myometrial PGE2/PGF2a receptors!), heavy menstrual bleeding (with Tranexamic Acid), acute dental/musculoskeletal pain, refractory pyrexia.

4. Therapeutic Indications & Evidence-Supported Uses

  • Primary dysmenorrhoea (uniquely blocks both prostaglandin synthesis AND uterine myometrial PGE2/PGF2a receptors!), heavy menstrual bleeding (with Tranexamic Acid), acute dental/musculoskeletal pain, refractory pyrexia

🇮🇳 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: Adults: 500 mg PO initial dose, then 250–500 mg TDS after meals for 3–5 days (Max 1500 mg/day for <=7 days)

Administration & Meal Timing: Take immediately AFTER meals with a full glass of water | Three times daily after Meals for 3–5 Days during menstruation or acute pain

6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment

Absorption & Disposition:
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Metabolism & Biotransformation:
Renal: Contraindicated if eGFR <30–45 mL/min or in dehydrated febrile children. Hepatic: Avoid in active liver disease
Elimination & Renal Adjustment:
Renal: Contraindicated if eGFR <30–45 mL/min or in dehydrated febrile children. Hepatic: Avoid in active liver disease
Hepatic Impairment Considerations:
Renal: Contraindicated if eGFR <30–45 mL/min or in dehydrated febrile children. Hepatic: Avoid in active liver disease

7. Contraindications, Precautions & High-Risk Warnings

Contraindications & Red-Flag Precautions:
  • IPC / CDSCO PvPI SAFETY ALERT (2023): Mefenamic acid carries a documented alert for DRESS Syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms)! Contraindicated in peptic ulcer, inflammatory bowel disease, CKD (eGFR <45 mL/min), Heart Failure, post-CABG, and 3rd trimester of pregnancy

Key Clinical Precautions: Renal: Contraindicated if eGFR <30–45 mL/min or in dehydrated febrile children. Hepatic: Avoid in active liver disease

8. Adverse Effects Profile

Common & Mechanism-Related Adverse Effects:
  • Diarrhoea (very characteristic of fenamates — if diarrhoea occurs, STOP Mefenamic Acid immediately!), dyspepsia, nausea, dizziness
  • DRESS syndrome (fever, widespread morbilliform rash, facial oedema, lymphadenopathy, eosinophilia, hepatitis/nephritis 2–8 weeks after exposure — PvPI Alert!), haemolytic anaemia, seizures in overdose, GI bleeding, AKI
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

  • Potentiates Warfarin and DOAC bleeding; increases Lithium and Methotrexate toxicity; Triple Whammy AKI with ACEi/ARB + Diuretic; avoid combining with other NSAIDs

10. Clinical Monitoring, Patient Counselling & Storage

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

Pharmacist Patient Counselling Points:

  • Patient Counselling Checklist: Take after food for a maximum of 5–7 days; stop immediately if you develop diarrhoea, skin rash, fever, or swollen glands (CDSCO PvPI safety alert); never give to a dehydrated child
  • Meal & Clock Timing Instruction: Take immediately AFTER meals with a full glass of water (Three times daily after Meals for 3–5 Days during menstruation or acute pain)
  • Missed Dose Protocol: Use PRN during painful menses; do not exceed 7 days
  • Geriatric Dispensing Pearl: Avoid in older adults due to high GI diarrhoea/ulcer and renal toxicity risk

Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Tablets: 250 mg, 500 mg; Paediatric Suspension: 100 mg/5 mL

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 Pharmacist Desk Reference — Professional Edition 2.7 (2026–27) • Ch 07 [7.16] (p. 86)

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: HANDBOOK_SOURCE_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.