Paracetamol (Acetaminophen)
Brand names: Panadol, Tylenol, Calpol, Adol
Analgesic / antipyretic
Paracetamol is the world's most widely used pain reliever and fever reducer. It is safe at recommended doses for most people — including pregnant women, children, and the elderly — but overdose is a leading cause of liver failure.
Drug Class
Analgesic / antipyretic
Category
Pain Relief
Forms Available
Tablets (500 mg, 1 g), Oral solution (paediatric)
How It Works
The exact mechanism is not fully understood. Paracetamol is thought to block the production of prostaglandins in the central nervous system and to modulate the endocannabinoid and serotonin systems, reducing the perception of pain and lowering the body's temperature set-point.
What It's Used For
- Mild to moderate pain — headache, toothache, muscle aches, period pain
- Fever (pyrexia) in adults and children
- Osteoarthritis pain (first-line by many guidelines)
- Post-operative pain (often combined with NSAIDs or opioids)
Available Forms
Side Effects
Common Side Effects
- Paracetamol is very well tolerated at therapeutic doses — side effects are rare
- Skin rash (uncommon)
- Nausea (usually if taken on an empty stomach)
Serious Side Effects
- Liver damage (hepatotoxicity) — the most serious risk, almost always from overdose or chronic excess
- Acute liver failure at doses above 7.5–10 g in adults
- Blood disorders (very rare at therapeutic doses)
Drug Interactions
- Warfarin — paracetamol in regular doses can slightly increase INR; monitor closely
- Alcohol — regular heavy alcohol consumption increases hepatotoxicity risk
- Enzyme-inducing drugs (rifampicin, carbamazepine, phenytoin) — increase production of the toxic metabolite NAPQI
When to Avoid
- Severe hepatic impairment or active liver disease — use with extreme caution or avoid
- Known allergy to paracetamol (rare)
Patient Tips
- The maximum dose for adults is 1 g (two 500 mg tablets) every 4–6 hours, up to 4 g per day
- Always check other medicines for hidden paracetamol — many cold/flu remedies contain it
- Do not exceed the recommended dose thinking more is more effective — it is not, and risks liver damage
- Take with food or milk if it upsets your stomach
- Store medications out of reach of children
Safe dosing: the critical rule
The standard adult dose is 500 mg–1 g (1–2 tablets) every 4–6 hours, to a maximum of 4 g (8 tablets of 500 mg) in 24 hours. This limit must not be exceeded.
Overdose — intentional or accidental from combining multiple paracetamol-containing products — is one of the most common causes of acute liver failure in the world. Symptoms of overdose may be delayed 24–72 hours; do not wait for symptoms before seeking emergency care after a suspected overdose.
Paracetamol in pregnancy
Paracetamol is the analgesic of choice during pregnancy — it does not carry the prostaglandin-inhibiting risks of NSAIDs, which can affect fetal kidney function and close the ductus arteriosus. It should still be used at the lowest effective dose for the shortest duration.
Recent epidemiological studies have raised questions about associations between prolonged prenatal paracetamol use and neurodevelopmental outcomes — discuss with your doctor if you need regular pain relief during pregnancy.
Is paracetamol better than ibuprofen for pain?
Neither is universally superior. Paracetamol is preferred when stomach, kidney, or cardiovascular safety is a concern. Ibuprofen (an NSAID) is often more effective for inflammatory pain — dental pain, muscle injuries, period pain — because it directly reduces inflammation. Combining the two at standard doses is safe and additive for moderate pain.
Related Medicines
Medical disclaimer
This page is for educational reference only. Always follow the dosage and instructions given by your prescriber or pharmacist. Do not start, stop, or change medicines without medical advice.
Reviewed 2026-06-01 · Looms Medical Team