A team of Monash University researchers have successfully piloted an algorithm to identify incorrect penicillin allergy labels and educate patients presenting to community pharmacies.
Patients are often inappropriately labelled as allergic to penicillin because they've experienced common side effects such as nausea or headache, as opposed to a true immune-mediated penicillin allergy which impacts less than one per cent of the population.
These incorrect penicillin labels are known as 'Type A' (a non true allergy) or 'non-immune mediated' penicillin reactions, which means reactions not triggered by the immune system.
The goal behind identifying and de-labelling incorrect penicillin allergy labels is to reduce inappropriate prescribing of antibiotics to improve patient safety and, ultimately, help in the fight against antimicrobial resistance (AMR) - which is largely driven by the overuse and misuse of antibiotics in healthcare.
The algorithm for identifying incorrect penicillin allergy labels took place across five pharmacies in metropolitan Victoria over seven weeks in 2024. Of the 18,646 patients who presented to the pharmacies during this time, 163 had a penicillin allergy label, of which 18.4 per cent were identified as having a Type A or non-immune mediated penicillin reaction history.
The study was led by Monash's Faculty of Pharmacy and Pharmaceutical Sciences (FPPS) and conducted by a team specialising in antibiotic allergy de-labelling programs and the role pharmacists play in supporting education of patients about incorrect antibiotic allergy labels.
One of the study's lead authors, Sharmila Khumra, who is a Monash University graduate now working as an Antimicrobial Stewardship pharmacist in a hospital setting, said incorrect penicillin allergy labels significantly increases the risk of patients being prescribed less effective broad-spectrum antibiotics.
"When a patient is incorrectly labelled as penicillin-allergic they may get prescribed a broader-spectrum antibiotic, which has several drawbacks including AMR," Ms Khumra said.
"While broad-spectrum antibiotics can be effective against a range of bacteria, their widespread use can lead to AMR, whereby bacteria becomes less susceptible to treatment. Addressing incorrect allergy labels provides prescribers and patients the opportunity to utilise first-line and appropriate antibiotics in lieu of second-line or inappropriate antibiotic choices."
Elise Mitri, also a lead author on the study and Monash University pharmacy graduate, is now working as a Drug Allergy and Immunology hospital pharmacist, while simultaneously undertaking a PhD in low-risk penicillin allergy de-labelling through the Doherty Institute.
"The impact of antibiotic allergy labels is well documented in the Australian setting. Ensuring community pharmacists have the appropriate tools to offer a standardised antibiotic allergy assessment and identify patients with an incorrect allergy label is imperative," Ms Mitri said.
Dr Angelina Lim, FPPS academic and Deputy Course Director said teaching pharmacists to de-label incorrect allergies in the community is an important part of antimicrobial stewardship.
"As medicine experts and frontline healthcare workers who are readily accessible to the community, we believe community pharmacists are well placed to provide penicillin allergy de-labelling support that will improve antibiotic prescribing for patients. We recognise that community pharmacies are busy and having a simple algorithm to follow may help support them make interventions day to day," Dr Lim said.
The algorithm itself comprises integration of adult and paediatric antibiotic allergy assessment tools, with all patients presenting to one of the community pharmacies within the seven-week period to ask advice or have their prescription fulfilled included in the study. All patients were asked a series of validated antibiotic allergy questions by the pharmacy students who had been trained to implement the algorithm by the clinical and research team.
More than three-quarters (77 per cent) of those with a Type A or non-immune mediated allergy label were receptive to education and de-labelling, whilst 23 per cent were hesitant or non-receptive due to various reasons, including disbelief that their allergy label is incorrect.
The authors concluded the algorithm can support everyday community pharmacy practice and reduce the risk of incorrect antibiotic allergy labels in the community.
The study was published in Infection, Disease and Health and is titled Implementation of a proposed algorithm to assess and de-label false penicillin allergy labels in the community.
DOI: https://doi.org/10.1016/j.idh.2025.04.002
