The role of a clinical pharmacist in spurious Penicillin allergy: a narrative review

Background A label of penicillin allergy is held by 6–10% of the general population and 15–20% of inpatients. > 90% of these labels are found to be spurious after formal allergy assessment. Carrying an unnecessary label of penicillin allergy is not benign. Such patients may receive second line, more expensive antibiotics, representing a significant impediment to antimicrobial stewardship. Aim of the review To (a) Explain the burden of spurious penicillin allergy, and evaluate the safety of direct oral penicillin challenge in ‘low risk’ patients (b) appraise the place for a clinical pharmacist-led penicillin allergy de-labelling programme. Method Narrative review. Search engines: PubMed, Google Scholar and Cochrane reviews. Search criteria: English language; search terms: penicillin allergy, antimicrobial stewardship, antimicrobial resistance, clostridium difficile, vancomycin resistant enterococci, risk stratification, clinical pharmacist and direct oral provocation test Results Penicillin allergy labels are associated with: longer hospital stay, higher readmission rates, enhanced risk of surgical site infections, risk of Clostridioides difficile infection and Methicillin resistant Staphylococcus aureus infection, a delay in the first dose of an antibiotic in sepsis and higher healthcare costs. A direct oral penicillin challenge in ‘low risk’ patients has proven to be safe. Discussion Recent studies including those led by a clinical pharmacist have demonstrated safety of a direct oral penicillin challenge in ‘low risk’ patients. This intervention needs validation within individual health services. Conclusion Direct oral penicillin challenge reduces the adverse impact of spurious penicillin allergy. A pharmacist-led penicillin allergy de-labelling program needs further validation in prospective multi-centre studies.