Issues for Surgery
Inadvertent paracetamol overdose if continued due to risk of multiple paracetamol-containing medicines being administered.
Risk of fatality if weight, renal impairment, and risk of hepatotoxicity are not considered when prescribing intravenous (IV), and potentially oral, paracetamol (see Further Information).
Difficulties with post-operative weaning / deprescribing of opioids if combination analgesic preparations containing paracetamol and an opioid are used.
Advice in the Perioperative period
Combination products: -
Consider checking liver function tests (LFTs) if patient has risk factors for hepatotoxicity (see Further Information).
Consideration should be given to prescribing the components of combination products as separate medicines perioperatively, to facilitate review of their appropriateness and encourage deprescribing (see Opioids monograph).
If dose(s) taken on day of surgery, ensure theatre staff are aware of timing of last dose to avoid inadvertent overdosing.
If taken regularly, restart post-operatively as soon as next dose is due, otherwise restart when needed.
Check anaesthetic records prior to administering in case of intraoperative administration.
If IV paracetamol is required post-operatively (e.g. due to unreliable oral absorption or swallowing difficulties) it is essential to check the dose, frequency, and cumulative dose in 24 hours is appropriate for patient’s weight, renal function and risk of hepatotoxicity (see Further Information). This should also be reviewed if clinical condition changes.
Combination analgesics such as tablets containing paracetamol with an opioid (e.g. co-codamol) should be avoided post-operatively as the fixed doses do not allow for titration to patient need, or the flexibility required for weaning (see Opioids monograph).
Interaction(s) with Common Anaesthetic Agents
Interaction(s) with other Common Medicines used in the Perioperative Period
Consult product literature and / or British National Formulary for dosing advice.
Reducing Oral Paracetamol Doses in Adults (for IV route see above)
There are case reports of malnourished patients, frail elderly patients, and patients with a history of liver disease developing acute liver failure following administration of oral paracetamol at dose of 4g daily. A reduction of the cumulative dose of oral paracetamol to 3g in 24 hours should be considered for malnourished patients or patients with Child Pugh C cirrhosis, irrespective of weight5.
In addition, a reduction in clearance of paracetamol has been associated with increased age and frailty1, 5. If a patient has a low body weight, increased age and / or frailty the risks and benefits of oral paracetamol, including the risks of hepatotoxicity and the potential risks of alternative treatments (e.g. Non-Steroidal Anti-inflammatory Drugs [NSAIDs], opioids), should be considered.
If a reduced oral paracetamol dose is prescribed, pain control should be monitored, and alternative management strategies offered if needed5. Patients should also be advised of the rationale for the lower dose as this will differ from the dosing advice on over-the counter paracetamol-containing products.