Reducing financial and environmental impact of medication use is an NHS priority. Paracetamol, a commonly prescribed critical care drug, can be given enterally (PO, NG, NJ or PEG) or intravenously (IV). Despite comparable efficacy, a 1g IV dose costs £1.51 versus £0.01 for oral (local pharmacy data), with 652g vs 38g CO2e [1, 2]. Our ICU, like most UK trusts, had no formal guideline for appropriate IV paracetamol use. This project aimed to characterise prescribing, develop guidance and re-audit impact.

Methods

Two retrospective audit cycles of four seven-day periods were undertaken on the adult ICU: cycle one (November 2024) and cycle two one year later. From the electronic patient record, for each administration we recorded route, indication and (for IV) clinical justification. After cycle one, a literature review and consensus discussions with ICU consultants, the pain lead and pharmacy team agreed indications for appropriate IV paracetamol use, presented to the ICU department and then formulated into a novel quick reference guideline (QRG). IV use was restricted to three main indications (further detail in the QRG): urgent pain in paracetamol-naive patients; urgent pyrexia (acute neurological injury, out-of-hospital cardiac arrest <72 h, ≥39 °C, or physiological distress); or enteral route contraindicated. Doses outside these criteria were classified as inappropriate. Daily review and step-down were encouraged. Cycle two used identical methodology.

Results

In cycle one, 1064 administrations were captured (50% IV, 50% enteral); 78% were for pain (60% enteral) and 22% for pyrexia (87% IV). In cycle two, 1570 administrations were captured (52% IV, 48% enteral). Indications for IV doses by cycle are shown in Table 1. Inappropriate IV use approximately halved (27% to 14%) despite a 47% rise in overall use, with estimated annual savings of £1,000 and 530kg CO2e.

Table 1. Indications for IV paracetamol administration by cycle.

Discussion

Our project halved inappropriate IV paracetamol use despite rising volume, suggesting genuine behaviour change. Its novelty is that no widely-adopted national guideline exists and most UK ICUs lack one; the QRG is portable for other units. Limitations include the single-centre retrospective design and the absence of patient-level outcome data. Next steps include incorporation into induction for new staff, EPR prompts, posters and re-audit at one year.

Acknowledgements

We thank the ICU pharmacy team for their support.