HSIB: Unintentional overdose of paracetamol in adults with low bodyweight (24 February 2022)

Summary

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

Paracetamol is a common painkiller often used as first-line management for mild to moderate pain. Although it is safe if taken at the right dose, paracetamol in large amounts is toxic to the liver and therefore the maximum dose must never be exceeded.

As its 'reference case', the investigation used the case 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 and towards the end of her admission, she developed multiorgan failure due to sepsis and was diagnosed with paracetamol-induced liver toxicity.

Content

Findings

• Oral paracetamol is a widely used medication that has few side effects for most people.
• There is limited data on how oral paracetamol affects adults with low bodyweight.
• Although liver toxicity is a recognised risk with oral paracetamol, evidence regarding the relationship between low bodyweight and the risk of liver toxicity is unclear.
• Two independent bodies are contracted to provide oral paracetamol prescribing guidance for clinicians. The information provided is not consistent.
• There is potential for electronic prescribing and medication administration systems to prompt healthcare providers to record a patient’s weight and consider liver toxicity in those who weigh less than 50kg.
• Environmental and other factors create challenges to the timely weighing of patients on a ward.

Safety observations

1. It may be beneficial for electronic prescribing and medication administration systems to include an alert for oral paracetamol that prompts documentation of a patient’s weight and consideration of the risk of liver toxicity when their weight is less than 50kg.
2. It may be beneficial for the evidence on oral paracetamol and low bodyweight to be reviewed by the relevant national bodies to reach a consensus and agree standardised prescribing guidance.
3. It may be beneficial for available technological solutions, such as beds with built-in scales, to be used to weigh patients. However, the cost of such equipment makes its widespread adoption within the NHS challenging.