All You Need to Know About Paracetamol: Uses, Dosage, and Safety Guide

Paracetamol — also known by its generic name acetaminophen — is one of the most widely used medicines in the UK. Sold under brand names including Panadol, Calpol, Hedex, and Dispril, it is a first-line treatment for mild to moderate pain and fever. Its accessibility and impressive safety record at recommended doses have made it a household staple for over 60 years. This guide covers everything you need to know: how it works, correct dosing, who should use caution, important drug interactions, and what to do in case of overdose.

How Does Paracetamol Work?

The precise mechanism by which paracetamol (acetaminophen) relieves pain and reduces fever is not fully understood — which is somewhat surprising given its decades of widespread use. The prevailing theories involve:

• Central nervous system action — paracetamol appears to block the synthesis of prostaglandins in the brain and spinal cord (central COX inhibition), reducing the brain’s perception of pain signals
• Endocannabinoid system — some evidence suggests paracetamol may be metabolised into a compound that activates cannabinoid-like receptors in the brain
• Antipyretic action — paracetamol reduces fever by acting on the hypothalamus (the brain’s temperature-regulating centre), resetting the “thermostat”

Unlike NSAIDs (ibuprofen, naproxen), paracetamol does not significantly reduce peripheral inflammation. This is why it is less effective for conditions where inflammation is the primary driver of pain — such as gout or acute arthritis. For inflammatory conditions, see our guides to naproxen and ibuprofen 600mg.

What Conditions Does Paracetamol Treat?

• Headache — one of the most common uses; effective for tension-type headache; can be combined with caffeine (as in some branded preparations) for added effect
• Migraine — effective for mild-moderate migraine, particularly when taken early in the attack
• Toothache
• Period pain (dysmenorrhoea) — less effective than NSAIDs for period pain due to absence of anti-inflammatory action; consider naproxen or ibuprofen first
• Cold and flu symptoms — relieves aches, fever, and sore throat
• Osteoarthritis — NICE recommends paracetamol as initial pain management; however, its modest effect size means it is often insufficient alone for moderate-severe osteoarthritis
• Post-operative pain — commonly used alongside stronger analgesics
• General muscle and joint aches

Paracetamol Dosage: Adults and Children

Paracetamol Overdose: A Medical Emergency

Paracetamol overdose is one of the most common causes of acute liver failure in the UK. Crucially, overdose does not always cause immediate, dramatic symptoms — you may feel relatively well for the first 24 hours, but irreversible liver damage can be occurring silently. Symptoms of liver damage appear 24–72 hours after overdose:

• Nausea and vomiting
• Abdominal pain (especially right upper quadrant)
• Jaundice (yellowing of skin and whites of eyes)
• Extreme fatigue
• Dark urine

Drug Interactions with Paracetamol

• Warfarin — regular high-dose paracetamol can enhance warfarin’s anticoagulant effect; regular INR monitoring is recommended
• Rifampicin, isoniazid (TB medications) — can increase the rate of formation of paracetamol’s toxic metabolite
• Carbamazepine, phenytoin, phenobarbital (epilepsy medications) — increase paracetamol metabolism, reducing its effectiveness and increasing toxic metabolite
• Alcohol — regular heavy drinking significantly increases the risk of paracetamol-induced liver damage; avoid large alcohol quantities while taking paracetamol

Paracetamol vs NSAIDs: Choosing the Right Painkiller

For stronger pain relief for inflammatory conditions, consider naproxen tablets or ibuprofen 600mg.