Paracetamol (Acetaminophen)
Dose Calculator
India's most used medicine — correct weight-based dosing for children and adults. Fever, pain, post-vaccination. Crocin · Calpol · Dolo · Metacin · Pyrigesic · Febrex. Oral, drops, suspension and IV covered.
Paracetamol Dose Calculator
🍺 Alcohol users: max 2g/day
🏥 Liver disease: max 2g/day, avoid in severe hepatic failure
⚖️ Weight <50 kg: 15 mg/kg per dose (same rule)
👴 Elderly: max 3g/day, watch for accumulation
💊 Combo products: Check for paracetamol in cold/cough syrups — easy to double-dose accidentally
Toxic dose: >150 mg/kg (adult) or >7.5g single dose
Do NOT wait for symptoms — liver damage is silent for 24–48h
Treatment: N-acetylcysteine (NAC) IV — most effective within 8h
Helpline: AIIMS Poison Control 1800-116-117
Paracetamol Dosing Reference Table — India
| Age / Weight group | Single dose (mg) | Drops 100mg/ml | Syrup 120mg/5ml | Syrup 250mg/5ml | Tablet | Max/day |
|---|---|---|---|---|---|---|
| 0–3 months (3–5 kg) Specialist | 30–50 mg | 0.3–0.5 ml | 1.25–2 ml | — | — | 4 doses |
| 3–6 months (6–7 kg) | 60–70 mg | 0.6–0.7 ml | 2.5 ml | — | — | 4 doses |
| 6–12 months (7–10 kg) | 70–100 mg | 0.7–1.0 ml | 3–4 ml | 1.5–2 ml | — | 4 doses |
| 1–3 years (10–15 kg) | 100–150 mg | 1.0–1.5 ml | 4–6 ml | 2–3 ml | — | 4 doses (max 60 mg/kg) |
| 3–6 years (15–20 kg) | 150–200 mg | 1.5–2 ml | 6–8 ml | 3–4 ml | ½ × 500mg (older) | 4 doses |
| 6–9 years (20–28 kg) | 200–280 mg | 2–2.5 ml | 8–10 ml | 4–5.5 ml | ½ × 500mg tab | 4 doses |
| 9–12 years (28–40 kg) | 280–400 mg | — | 10–15 ml (large volume) | 5.5–8 ml | ½–1 × 500mg tab | 4 doses |
| 12–16 years (40–50 kg) | 400–500 mg | — | — | 8–10 ml | 1 × 500mg tab | 4 doses |
| Adult / ≥16 yr (≥50 kg) | 500–1000 mg | — | — | — | 1–2 × 500mg or 1 × 650mg or 1 × 1000mg | 4g/day (3g in practice) |
Paracetamol in India — The Complete Clinical Guide
Paracetamol (acetaminophen, Crocin, Dolo, Calpol) is India's most widely used and most purchased medicine — sold in over 10 billion tablets annually. It is the first-line drug for fever and mild-to-moderate pain recommended by the WHO, Indian Academy of Pediatrics (IAP), and BNF. Despite its widespread use, paracetamol is one of the most commonly overdosed drugs in India, and incorrect dosing (both under-dosing and over-dosing) remains a significant problem — particularly in paediatric practice where weight-based dosing is frequently not followed.
How paracetamol works
Paracetamol reduces fever and pain through central mechanisms — it is believed to inhibit a variant of cyclooxygenase (COX-3) within the brain and spinal cord, reducing prostaglandin synthesis centrally without the peripheral anti-inflammatory activity of NSAIDs. This means it is effective for fever and mild-to-moderate pain but does not reduce joint inflammation (unlike ibuprofen or diclofenac). Its lack of platelet inhibition makes it safe after surgery and in dengue fever, where NSAIDs are dangerous.
Why weight-based dosing is essential in children
The correct paracetamol dose for children is always based on body weight — not age alone. The standard dose is 10–15 mg per kg body weight per dose, given every 4–6 hours, with a maximum of 4 doses in 24 hours. Using age-based "teaspoon" instructions printed on many Indian syrup bottles is inaccurate because children's weight varies enormously for any given age. A 3-year-old may weigh anywhere from 10 to 18 kg — the dose difference is almost double. Always weigh the child and calculate the dose.
💡 The most common paediatric dosing error in India
- Under-dosing: Giving "half a teaspoon" to all infants regardless of weight. A 10 kg infant needs 100–150 mg per dose — half a teaspoon of Crocin 120mg/5ml is only 60 mg (sub-therapeutic). The fever does not come down → parents give ibuprofen too → unnecessary dual NSAID use.
- Over-dosing: Giving adult tablets (500mg) to a 15 kg child — this is 33 mg/kg, well above the 15 mg/kg maximum per dose.
- Frequency errors: Giving paracetamol every 2–3 hours when fever does not come down → exceeds maximum 4 doses/day → accumulation and liver risk.
- Combination products: Giving Crocin syrup + Febrex Plus (which also contains paracetamol) simultaneously → double dose of paracetamol.
Paracetamol for fever — what temperature to treat?
Paracetamol should be used to relieve fever-related discomfort, not simply to normalise the temperature number. The IAP and WHO advise treating fever with antipyretics when the child is uncomfortable, distressed, or unable to sleep — not as a reflex response to any reading above 37.5°C. A fever of 38.5°C in a playful, comfortable child does not require medication. Antipyretics should be given when temperature is above 38.5°C (axillary) or above 38°C (rectal/tympanic) and the child appears unwell, irritable, or unable to feed/sleep. Treating fever does not prevent febrile seizures — the IAP has explicitly removed this as an indication for routine antipyretic use.
Paracetamol vs ibuprofen for fever — when to use which
Both paracetamol and ibuprofen are effective antipyretics. Key differences:
- Paracetamol: Safe from birth, safe in dengue fever (does not affect platelet function), safe in asthma (most asthmatics tolerate it), safe with food or without, no GI irritation. Duration: 4–6 hours.
- Ibuprofen: Stronger anti-inflammatory, slightly longer duration (6–8 hours), more effective for musculoskeletal and dental pain. Contraindicated in dengue, chickenpox, significant dehydration, renal impairment, and children under 6 months. Give with food.
- Alternating: Some paediatric guidelines permit alternating paracetamol and ibuprofen (giving one, then the other after 2–3 hours) for prolonged fever — this can provide smoother temperature control. However, it risks parental confusion about total dosing and accidental overdose. Not routinely recommended by IAP as a first-line strategy.
Adult dosing — Dolo 650, Crocin 650, and the Indian 650mg tablet
India has developed a strong preference for 650 mg paracetamol tablets (Dolo 650, Crocin 650, Calpol 650) over the 500 mg tablets used in most other countries. The 650 mg strength provides a dose that is intermediate between the 500 mg and 1000 mg options — one tablet four times daily delivers 2.6g/day, comfortably within the safe limit. The maximum adult dose remains 1g (1000 mg) per dose and 4g (4000 mg) per day, but the practical recommended limit for regular use is 3g per day. Dolo 650 became enormously popular during the COVID-19 pandemic in India, to the point where it became the subject of significant public attention and regulatory scrutiny of its marketing practices.
Paracetamol in liver disease and alcohol use
Contrary to widespread belief, paracetamol is NOT contraindicated in patients with stable liver disease — in fact, it is the preferred analgesic for patients with chronic liver disease precisely because NSAIDs are harmful to the kidneys and carry GI bleeding risk in cirrhosis. However, the maximum dose must be reduced: 2g per day (four doses of 500 mg) for patients with significant liver disease or regular alcohol use. Paracetamol is contraindicated only in acute liver failure (fulminant hepatic failure) or when the patient is actively drinking heavily and malnourished (which depletes glutathione, increasing toxic metabolite accumulation).
IV paracetamol (Perfalgan) — when and how
Intravenous paracetamol (Perfalgan 10 mg/ml in 100 ml glass vial) is used in hospital settings when oral or rectal administration is not possible — post-operative patients, patients with severe vomiting, or in the ICU. The bioavailability of IV paracetamol is 100% (vs ~85% oral), so the IV dose is the same as the oral dose, not higher. Adult dose: 1g IV every 4–6 hours, maximum 4g/day. For adults weighing less than 50 kg: 15 mg/kg IV every 4–6 hours, maximum 60 mg/kg/day. Infuse over 15 minutes. IV paracetamol is significantly more expensive than oral — restrict to genuinely appropriate indications.
🚨 Paracetamol overdose — what every Indian doctor and parent needs to know
- Toxic dose: Above 150 mg/kg body weight (adult: above 7.5g single ingestion; child: above 150 mg/kg)
- The deceptive danger: In the first 24 hours after overdose, the patient may feel only mild nausea and appear well. Liver damage develops silently between 24–96 hours. By the time jaundice and liver failure are obvious, it may be too late for effective treatment.
- Treatment — N-acetylcysteine (NAC): IV NAC (Parvolex) is the specific antidote. Most effective within 8 hours of ingestion (nearly 100% effective). Still useful up to 24 hours. Requires paracetamol blood level measured at 4+ hours post-ingestion to guide treatment decision (Rumack-Matthew nomogram).
- Act immediately: Any patient who has taken >7.5g paracetamol (adult) or >150mg/kg (child), regardless of symptoms → A&E immediately. Poison helpline: AIIMS 1800-116-117.
- Do not give paracetamol again until the situation is assessed.
Paracetamol during pregnancy and breastfeeding
Paracetamol has been the analgesic of choice during pregnancy for decades, considered safe across all trimesters at standard therapeutic doses for short-term use. Recent observational studies have suggested a possible association between prolonged paracetamol use in pregnancy and neurodevelopmental outcomes in children, but this evidence is contested and does not change the recommendation that short-term use (1–3 days) at standard doses for genuine pain or fever is appropriate and safe. For chronic pain management in pregnancy, obstetric specialist input is needed. NSAIDs are contraindicated in the third trimester (premature ductus arteriosus closure). Paracetamol is safe during breastfeeding — only minimal amounts pass into breast milk.
Drug interactions with paracetamol
Paracetamol has few clinically significant drug interactions compared to NSAIDs, but important ones include:
- Warfarin: Regular paracetamol (≥4 doses/week) increases INR. Monitor INR closely in anticoagulated patients on regular paracetamol. NSAIDs are more dangerous with warfarin due to GI bleeding risk, but paracetamol's INR effect is still clinically significant.
- Alcohol (chronic heavy use): Induces CYP2E1, which metabolises paracetamol to the toxic NAPQI metabolite — increasing hepatotoxicity risk at even standard doses. Limit to 2g/day maximum in heavy drinkers.
- Isoniazid: Similarly induces CYP2E1 — patients on TB treatment need to be cautious about paracetamol dose and duration.
- Combination products: Check all other medications for hidden paracetamol content — many Indian cold preparations, combination pain tablets, and cough syrups contain paracetamol. Total daily intake from all sources must stay below maximum.