1. Clinical & Scientific Overview
Paracetamol (Acetaminophen) (TIP-MED-000103, Reference Code [7.1]) is classified under
Pain, Inflammation, Rheumatology & Gout Medicines (Ch 07) as a Non-Opioid Central Analgesic & Antipyretic (Central COX/Prostaglandin & Endocannabinoid/TRPV1 Modulator).
Within the Indian regulatory and compendial framework, it is governed under Non-Schedule / OTC (Standard packs) • CDSCO FDC Dosage Cap Regulated.
Crocin (GSK), Dolo 650 (Micro Labs), Calpol (GSK), Pacimol (Ipca)
Oral Uncoated Tablets: 500 mg, 650 mg; Sustained-Release (SR/ER) Bilayer Tablets: 1000 mg; Paediatric Syrup/Suspension: 120 mg/5 mL, 250 mg/5 mL; Drops: 100 mg/mL; IV Infusion: 1000 mg/100 mL (10 mg/mL)
3. Mechanism of Action & Pharmacodynamics
Inhibits prostaglandin H2 synthase (COX-1/COX-2 peroxidase active site) selectively within the central nervous system where peroxide tone is low, reducing hypothalamic PGE2 synthesis to reset the thermoregulatory set-point (antipyresis). Also metabolized in the brain by FAAH to AM404, which activates endocannabinoid CB1/TRPV1 pathways and descending serotonergic pain inhibition. Weakly active in inflamed peripheral tissues (high peroxide levels neutralize Paracetamol), explaining its lack of peripheral anti-inflammatory or antiplatelet effects.
4. Therapeutic Indications & Evidence-Supported Uses
- Symptomatic relief of fever (antipyretic of choice across all age groups)
- Mild-to-moderate acute and chronic pain (headache, dental pain, osteoarthritis, post-vaccination pyrexia)
5. Educational Dosage Context, Formulations & Administration
Educational Dosing & Regimen Summary: Adults: 500–1000 mg orally every 4–6 hours as needed (Strict maximum: 4,000 mg/24 hr in healthy adults; 2,000–3,000 mg/24 hr in chronic alcohol use, malnutrition, or low body weight <50 kg). Children: 15 mg/kg/dose q6h (max 60 mg/kg/day).
Administration & Meal Timing: Oral, Rectal, or Intravenous infusion over 15 minutes.
6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Contraindicated in acute liver failure; in stable compensated cirrhosis or chronic alcohol use, restrict maximum daily dose to <=2,000 mg/day.
Safe analgesic of choice in CKD; extend dosing interval to q6h (CrCl 10–50 mL/min) or q8h (CrCl < 10 mL/min).
Contraindicated in acute liver failure; in stable compensated cirrhosis or chronic alcohol use, restrict maximum daily dose to <=2,000 mg/day.
7. Contraindications, Precautions & High-Risk Warnings
- Severe active hepatic insufficiency or acute hepatitis
- Hypersensitivity to Paracetamol
Key Clinical Precautions: Contraindicated in acute liver failure; in stable compensated cirrhosis or chronic alcohol use, restrict maximum daily dose to <=2,000 mg/day.
8. Adverse Effects Profile
- Well tolerated at therapeutic doses (virtually zero GI ulceration, zero platelet inhibition, and zero renal afferent vasoconstriction)
- Acute or staggered overdose (>7.5–10 g or >150 mg/kg) causes centrilobular (Zone 3) hepatic necrosis, acute liver failure, and renal tubular necrosis (treated with N-Acetylcysteine within 8 hours using the Rumack-Matthew nomogram)
- Rare severe cutaneous reactions (SJS/TEN/AGEP)
- Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.
9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions
- Chronic Alcohol, Isoniazid, Phenytoin, Carbamazepine: induce hepatic CYP2E1 and deplete glutathione stores, increasing toxic NAPQI generation
- Warfarin: regular intake >2 g/day for >3–5 days inhibits Vitamin K epoxide reductase and elevates INR
- Multiple OTC cold/pain FDC products: accidental supratherapeutic overdose due to duplicate hidden Paracetamol
10. Clinical Monitoring, Patient Counselling & Storage
Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.
Pharmacist Patient Counselling Points:
- Check all other cold, flu, and pain medicines to ensure total Paracetamol intake from all sources NEVER exceeds 4,000 mg (six 650 mg tablets or eight 500 mg tablets) in 24 hours.
- Verify paediatric strength carefully (drops 100 mg/mL vs suspension 125 mg/5 mL vs 250 mg/5 mL) and dose strictly by child's weight in kg.
- Avoid alcohol while taking Paracetamol.
Storage, Stability & Dispensing Safeguards: Store below 30°C protected from light and moisture.
11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)
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.