Paracetamol

How it works

Its precise mechanism is incompletely understood but is thought to involve central inhibition of prostaglandin synthesis, with little peripheral anti-inflammatory effect.

Prescribing in practice

• Overdose causes potentially fatal hepatotoxicity; counsel patients not to exceed the recommended maximum daily intake and to check that other combination products do not also contain paracetamol.
• Dose reduction or extended dosing intervals are advised in hepatic impairment, chronic alcohol use, low body weight and other risk factors for liver injury.
• Acute overdose is managed urgently with acetylcysteine guided by serum paracetamol levels and a treatment nomogram; refer to current poisoning guidance.

Monitoring

Routine monitoring is not required at therapeutic doses, but liver function and paracetamol levels are checked after suspected overdose.

Counselling the patient

• Do not take more than the stated dose, and do not combine multiple paracetamol-containing products.
• Seek urgent medical help after any overdose even if you feel well.
• Tell a clinician if you drink alcohol regularly or have liver problems.

Evidence & guidelines

Paracetamol is a long-established first-line agent for pain and fever recommended across UK and international guidelines.