Embedding penicillin de-labelling in the AMU: a feasibility and safety pilot study with exploratory economic and environmental analysis.

BACKGROUND

Penicillin allergy labels affect 6-10% of the UK population, yet over 95% are inaccurate. These labels drive unnecessary broad-spectrum antibiotic use, antimicrobial resistance, healthcare costs, adverse patient outcomes and carbon emissions.

METHODS

This pilot study embedded a penicillin allergy de-labelling (PADL) clinic within an Acute Medical Unit, using a direct oral amoxicillin challenge for patients identified as low-risk for a true allergy to penicillin according to BSACI guidelines and PEN-FAST scoring. Primary outcomes were feasibility and safety. Secondary outcome was subsequent antibiotic prescribing patterns. Exploratory outcomes included retrospective economic, antimicrobial resistance and environmental impact modelling.

RESULTS

Sixty patients (mean age 56 years) were included in the study, of whom 59 (98%) were successfully de-labelled with one delayed type IV reaction but no anaphylaxis. Following de-labelling, 35% received subsequent antibiotic therapy and all were prescribed penicillin-based therapy. Retrospective analysis revealed antibiotic costs were approximately tenfold higher (£19,364 versus £2,092) due to allergy labels. Multidrug-resistant organisms were present in 47% of patients and 37% received unnecessary intravenous antibiotics.

CONCLUSION

This pilot suggests that AMUembedded penicillin delabelling is safe and feasible, and may be associated with important clinical, economic, antimicrobial stewardship and environmental benefits that warrant confirmation in larger studies.