Weight a minute - iatrogenic paracetamol toxicity is preventable by utilisation of well-designed drug charts

Abstract

Iatrogenic Paracetamol toxicity is a potentially life-threatening yet avoidable cause of acute liver failure. Unfortunately, several cases have recently been reported nationally (1,2). The impetus behind our project was a recent case of iatrogenic Paracetamol induced hepatotoxicity within our trust, a London-based District General Hospital. According to the British National Formulary, for adults weighing 10-50kg the intravenous (IV) dose is 15mg/kg every 4-6hours (max. 60mg/kg daily), not the usual 1 gram QDS oral dose which is applied irrespective of weight (3). We audited 100 adult patients in April 2013 and re-audited in July 2013. Both of the randomly selected samples consisted of an equal number of surgical and medical patients, with an equal gender ratio. Data of interest included whether patients were on IV Paracetamol, appropriately dosed; if and when patients had been weighed during admission; and whether the WHO pain ladder of analgesia was followed. Identified shortcomings included patient weight on admission not being recorded, and IV Paracetamol dose adjustment not being made in patients <50kg. 3 months were spent raising awareness of the importance to record patient weights and to dose-adjust IV Paracetamol when indicated. Patients weighed on admission improved from 37% to 68% (p<0.0001) and those on the inappropriate dose of Paracetamol fell from 18 (25% of the patients on Paracetamol) to 5 (5.75% of the patients on Paracetamol) p=0.0013. There was a marked improvement in the number of patients with the weight written on their drug chart from 27% to 53% post-intervention. (p=0.0003) In conclusion, every patient should be weighed on admission. In order to prevent potential hepatotoxicity, staff should document patient weights on the drug charts and be aware of the fact that patients who weigh <50 kg should be on a 15 mg/kg/dose of IV Paracetamol, not 1 gram QDS.