Paracetamol

How it works

It produces analgesia and antipyresis through poorly characterised central inhibition of prostaglandin synthesis and modulation of central pain pathways, with little peripheral anti-inflammatory effect.

Prescribing in practice

• Hepatotoxicity in overdose is the key hazard; total intake from all combination products must be counted and the maximum daily dose not exceeded, with lower ceilings considered in low body-weight or chronic-malnutrition states.
• It is the preferred analgesic in pregnancy and breastfeeding, with NSAIDs avoided in the third trimester and opioids reserved for severe pain.
• Effective for many obstetric and gynaecological pains but inadequate alone for severe procedural or post-operative pain, where multimodal analgesia is needed.

Monitoring

Routine monitoring is not required at therapeutic doses, but in suspected overdose timed plasma paracetamol concentrations and liver function guide acetylcysteine treatment.

Counselling the patient

• Do not take other products containing paracetamol at the same time, as accidental overdose can seriously damage the liver.
• It is considered safe in pregnancy and breastfeeding when taken at the recommended dose for the shortest time needed.
• Seek urgent help after any overdose even if you feel well, because liver injury can be delayed.

Evidence & guidelines

Paracetamol is endorsed by NICE and UK obstetric guidance as the analgesic and antipyretic of choice in pregnancy.