Management overview for unintentional paracetamol poisoning

For paracetamol poisoning presenting in primary care, see Paracetamol poisoning: advice for primary care providers.

Ingestion of paracetamol with the intention of harm is outside the scope of this monograph. See:

Paracetamol is widely available and responsible for a large proportion of accidental and deliberate cases of poisoning. Paracetamol poisoning is common, but rarely causes severe liver injury or death. Children younger than 6 years are less susceptible to paracetamol toxicity (see Paracetamol poisoning: liquid formulations in a child younger than 6 years).

This monograph discusses paracetamol poisoning due to unintentional supratherapeutic doses (also referred to as repeated supratherapeutic ingestion [RSTI]). In this scenario, patients do not intentionally take an overdose, but may take more frequent, or higher than recommended doses for a number of consecutive days for a therapeutic purpose (eg pain, viral illness). An important feature of unintentional paracetamol poisoning is that there is a higher risk of poor outcomes compared with cases of intentional poisoning, because commencement of acetylcysteine therapy is usually delayed. For this reason, the threshold for treatment with acetylcysteine is much lower in patients with unintentional paracetamol poisoning.

This monograph also covers the management of patients who have symptoms of acute liver injury (eg abdominal pain, nausea, vomiting) following therapeutic doses of paracetamol. Certain individuals are at greater risk of toxicity due to advanced age, comorbidities, alcohol use, nutritional status (eg prolonged fasting), concurrent drugs, and genetics.

If the patient meets the criteria for unintentional paracetamol poisoning (see Toxic dose), measure the:

  • serum paracetamol concentration
  • serum alanine aminotransferase (ALT) concentration.

If the investigation results indicate a toxic paracetamol concentration and acute liver injury1, acetylcysteine therapy is indicated2.

For advice on the management of acute paracetamol poisoning presenting to rural and remote facilities lacking pathology services, refer to the 2019 Australian and New Zealand guidelines for the management of paracetamol poisoning3.

Gastrointestinal decontamination with activated charcoal is not indicated in the setting of unintentional paracetamol poisoning because the paracetamol has been ingested over a long period.

1 Liver injury has various definitions; the Toxicology and Toxinology Expert Group uses a definition of a serum alanine aminotransferase (ALT) concentration of 50 U/L or higher.Return
2 Acetylcysteine is also commonly known as N-acetylcysteine, and the abbreviation ‘NAC’ is used in many texts and local protocols.Return
3 Chiew AL, Reith D, Pomerleau A, Wong A, Isoardi KZ, Soderstrom J, et al. Updated guidelines for the management of paracetamol poisoning in Australia and New Zealand. Med J Aust 2019. [URL] Return