An older person with short, grey hair lays in a hospital bed. They have an unhappy look on their face.

Unintentional overdose of paracetamol in adults with low bodyweight

HSIB legacy content

HSIB legacy content

This investigation was carried out by the Healthcare Safety Investigation Branch (HSIB). Find out more about HSIB legacy.

Investigation summary

This investigation explores the prescription of oral paracetamol in adult inpatients who, on admission to hospital, have low bodyweight (less than 50kg).

It specifically focuses on the dose of oral paracetamol prescribed and given to this group of patients while in hospital, and the processes for ensuring weight is accurately recorded.

Paracetamol is one of the most commonly prescribed painkillers in the world. It’s often used as first-line management for mild to moderate pain. When taken appropriately it has a low risk of toxic effects. However, it is known that paracetamol in large amounts is toxic to the liver and therefore the maximum dose must never be exceeded.

Our findings and safety observations aim to increase awareness of the potential for paracetamol toxicity in adults with low bodyweight. Some of the findings and conclusions may also be applicable to other medications that have the potential to cause harm in patients with low bodyweight.

As an example, which is referred to as ‘the reference event’, the investigation considered the experience of Dora, an 83-year-old woman who weighed less than 50kg on admission and lost further weight in hospital.

While in hospital Dora was prescribed oral paracetamol 1g four times a day.

Towards the end of her admission, Dora developed multiorgan failure due to sepsis and was diagnosed with paracetamol-induced liver toxicity.

This investigation looks at:

  • the contextual factors surrounding the prescription of paracetamol in adult inpatients
  • the systemic factors influencing unintentional overdose of paracetamol in adult inpatients
  • opportunities to mitigate the risk of prescribing paracetamol in adult inpatients.
Investigation report