A two-week-old 2.9 kg baby presented to a general hospital emergency department with acute bowel obstruction and underwent urgent laparotomy. Postoperatively the baby was given three doses of 290 mg intravenous paracetamol (instead of the prescribed 29 mg dose) over a 38-hour period. The error was detected 1–2 hours after the third dose, which was initially thought to be a single overdose. The preceding two overdoses were discovered six hours later and N-acetylcysteine was given, following the advice of a Poisons Information Centre toxicologist. The baby remained clinically stable and liver transaminases were normal throughout.
A 5.65 kg infant admitted to a general hospital was prescribed '80 mg paracetamol IV/PO/PR'. Poor legibility of the prescription led to interpretation of the dose as 280 mg. A 1000 mg vial of intravenous paracetamol was connected to an infusion pump set at 168 mL/hr for 10 minutes. The infusion continued beyond the intended duration and a total dose of 430 mg (75 mg/kg) was given.
- Reserve intravenous paracetamol for acute, short-term treatment of mild–moderate pain when enteral administration is not possible.
- Undertake a comprehensive risk assessment before treatment and review daily – exercise particular caution in infants less than six months of age. General risk factors for paracetamol hepatotoxicity in paediatric patients (see Box) and for underweight adults and frail older people less than 50 kg are described in relevant sections of NSW TAG's guidance.
- Follow general principles for safe paediatric prescribing,4 including:
- always write legibly – printing in capitals is strongly recommended
- check the basis for the dose calculation in a current paediatric prescribing reference or other up-to-date, evidence-based medicines information resource
- calculate the dose using the patient's current, accurate (or, for overweight children, ideal) body weight (advice on how to estimate ideal body weight using paediatric growth charts is provided in the guidance)
- independently double check the calculated dose (using a calculator) at the time of prescribing and at each administration
- prescribe the dose in milligram (mg) units. Additional specification of the volume in millilitres (mL) and the strength of the solution may maximise the clarity of the intended dose for liquid medicines, but the primary order should always be expressed in dose units.
Box - Key risk factors for paracetamol hepatotoxicity *
vomiting or dehydration
severe hepatic impairment
* adapted from reference 1
Conflict of interest: none declared
Acknowledgements: Thanks to Jared Brown, Senior Poisons Specialist, and Dr Naren Gunja, Medical Director, NSW Poisons Information Centre, for their help with case identification. The valuable contribution of the NSW TAG Paracetamol Expert Advisory Group and the NSW TAG Editorial Committee to the development of NSW TAG's guidance document is also gratefully acknowledged.
- NSW Therapeutic Advisory Group. Intravenous paracetamol use. 2012. Addendum to the 2008 'Paracetamol use' position statement of the NSW Therapeutic Advisory Group. www.ciap.health.nsw.gov.au/nswtag/documents/publications/position-statements/paracetamol-ivaddendum-dec-2012.pdf [cited 2014 Jan 7]
- Therapeutic Goods Administration. Medicines Safety Update: Accidental paracetamol poisoning. Aust Prescr 2012;35:122.
- Doherty C, McDonnell C. Tenfold medication errors: 5 years' experience at a university-affiliated pediatric hospital. Pediatrics 2012;129:916-24.
- Gazarian M, Graudins LV. 'Safe Prescribing' and 'Paracetamol' guidelines. In: Supplemental Information (SI 1-10). Long-term reduction in adverse drug events: an evidence-based improvement model. Pediatrics 2012;129:e1334.