Evaluation of a pharmacist-led penicillin allergy testing service in a community health system

Unpacking Oral Challenge Protocols: A Descriptive Epidemiologic Study of Reactions, Predictors, and Practices for Delabeling Low-Risk Penicillin Allergies Leveraging Data from a Systematic Review and Meta-Analysis

Background: Oral challenges with amoxicillin or other penicillins are safe and effective for delabeling low-risk penicillin allergy histories. While approximately 90% of reported penicillin allergies can be safely delabeled, detailed data on reaction frequency, types, and timing during and after delabeling interventions remain limited. Such data are crucial to optimizing protocols and integrating oral challenges into routine practice. This study aims to characterize the interventions commonly used for oral challenge, classify reported reactions, and identify reported predictors of hypersensitivity reactions in randomized controlled trials and quasi-experimental studies involving an oral challenge for patients with low-risk penicillin allergies. Methods: This study leverages data from a systematic review and meta-analysis assessing the effectiveness of oral challenge interventions in patients with low-risk penicillin allergies. This descriptive analysis summarizes the adverse reactions experienced among patients in published studies who received oral challenge. Participant demographics, intervention protocols, frequency, type, and timing of post-challenge adverse reactions are reported. Reactions are categorized as immediate, delayed, or other, with frequencies summarized using descriptive statistics. A random effects meta-analysis quantifies a pooled adverse reaction rate. Predictors of hypersensitivity reactions were synthesized narratively. Results: Across 26 studies (2 randomized trials, 24 quasi-experimental studies) evaluating an oral challenge for patients with a low-risk penicillin allergy, the average participant age was 56 years, with a predominance of females (61%) and limited ethnic diversity with 88% reported or identifying as White. Amoxicillin was the most frequenty used oral challenge agent, typically administered as a single 250 mg oral dose. The incidence of reaction or non-delabeling was 4% (95% Confidence Interval 3%, 6%), I 2 = 43%, P = .0001. Cutaneous manifestations, such as rashes, were the most frequent reactions. Delayed reactions, primarily mild maculopapular rashes, were uncommon and managed with antihistamines or topical steroids. Risk factors for oral challenge reactions included higher baseline allergy burden and shorter intervals to oral challenge since the index reaction. Conclusion: Oral challenge strategies to delabel low-risk penicillin allergies can involve single doses of amoxicillin or other penicillins with monitoring protocols that can be managed in ambulatory settings. However, although these delabeling strategies are becoming more prevalent, continued study of standardized protocols and follow-up are essential for effective and replicable delabeling strategies. Future research should prioritize diverse populations and equity-driven frameworks to improve generalizability to all individuals and to resource limited settings.

Implementation of a pharmacist-led outpatient penicillin allergy testing clinic

BACKGROUND

Penicillin allergies affect approximately 10% of the population, leading to increased health care costs, treatment failures, and multidrug resistant organisms.

OBJECTIVE

To determine the feasibility of implementing a pharmacist-led outpatient penicillin allergy testing program.

METHODS

This single-site, retrospective cohort study was conducted from July 2022 through December 2023. The study site consisted of an outpatient clinic within a nonacademic community hospital. The primary outcome was the percentage of patients who had their penicillin allergy delabeled. Secondary outcomes included percentage of patients who received appropriate antibiotics following allergy delabeling, incidence and type of immunoglobulin E mediated penicillin reactions, number of patients who were relabeled with a penicillin allergy, number of orthopedic patients with a postoperative surgical site infection, average reimbursement per patient, and average appointment time.

RESULTS

A total of 457 outpatients received penicillin allergy testing during the study period. Physician specialties who referred patients were orthopedics, obstetrician-gynecologists, infectious disease, urology, urogynecology, cardiothoracic surgeons, and primary care providers. For the primary outcome, 439 patients (96%) were successfully delabeled. All delabeled patients received appropriate antibiotics following testing. There were 17 patients who developed minor itching with or without a localized rash following the amoxicillin challenge, and one patient had a delayed reaction of rash 12 hours after the amoxicillin that resolved with an antihistamine. One patient had their penicillin allergy relabeled. Of the 192 orthopedic patients, 0 patients had a postoperative surgical site infection. The average reimbursement was $423 per patient with the average appointment lasting 96 minutes.

CONCLUSION

Pharmacists, in collaboration with multiple physician specialties, successfully implemented an outpatient penicillin allergy testing service to safely delabel patients and support antimicrobial stewardship.

A systematic review and meta-analysis of interventions to delabel low-risk penicillin allergies with consideration for sex and gender

AIMS

Sex and gender may influence penicillin allergy label (PAL) prevalence and outcomes. This review evaluates the effectiveness and safety of direct delabelling (DD) and oral challenge (OC) for low-risk patients and examines sex and gender differences in reporting and outcomes.

METHODS

We searched PubMed, Database of Abstracts of Reviews and Effects, ClinicalTrials.gov, Cochrane Database of Systematic Reviews, International Pharmaceutical Abstracts, medRxiv, Ovid MEDLINE, and Ovid EMBASE until February 2024 for studies including DD or OC compared to no intervention, skin testing or other methods. Two reviewers assessed quality. Meta-analyses were conducted, and subgroup analyses were carried out if I2 >   75%. Descriptive data was analysed using NVivo 14 and reported narratively.

RESULTS

From 1046 screened studies, 28 met inclusion criteria (two RCTs, 26 quasi-experimental studies). Sex at baseline was reported in 86% of studies, with 61% females: 18% disaggregated outcomes by sex with a female mean delabelling rate of 66%. Gender variables were not reported. OC was not found to be more or less as effective comparaed to skin testing in RCTs (risk ratio [RR] 1.04; 95% confidence interval [CI] 0.95, 1.13, I2 = 74%). DD interventions had a 27% delabelling rate (95% CI 10%, 50%, I2 = 96%), with nursing staff achieving 29% (95% CI 15%, 47%, I2 = 63%) and allergists/immunologists 6% (95% CI 0.00, 0.00, I2 = 20%). Quasi-experimental studies reported 90% delabelling for OC, with 59% by allergists/immunologists and 90% by pharmacists. Adverse events averaged 4% and were non-severe.

CONCLUSIONS

DD and OC are effective for delabelling low-risk penicillin allergies. Comprehensive data is lacking on sex and gender differences, indicating a need for further research.

Impact of a drug allergy education course for non-specialists: Findings from ADAPT-A randomized crossover trial

BACKGROUND

The consequences of drug allergy remain a global health concern. Drug allergy is often a neglected topic and many non-specialists lack sufficient knowledge or confidence in evaluating or managing this common condition. Evidence-based interventions to better equip non-specialists to tackle drug allergy are needed. The aim of the study is to evaluate the effectiveness of an intensive educational course on drug allergy knowledge and practice of non-specialists.

METHODS

A randomized crossover trial (NCT06399601) was conducted among practicing physicians and nurses participating in an intensive drug allergy course-Advances in Drug Allergy & Penicillin Testing (ADAPT). Participants' baseline knowledge and self-reported practices were assessed with standardized questionnaires (scored from 0 to 100, with "satisfactory" defined as ≥60/100). Participants were randomized into two cohorts and attended ADAPT at different time points. Serial responses before and after the course were compared within and between cohorts.

RESULTS

Seventy participants (25 physicians, 45 nurses) randomized into two groups completed the course. Baseline drug allergy knowledge (58.0 ± 19.9) and self-reported practice (36.9 ± 24.3) were unsatisfactory among non-specialists, with significantly lower scores from nurses than physicians in both domains (knowledge: 49.0 ± 17.4 vs. 74.0 ± 12.7; practice: 32.1 ± 21.3 vs. 53.3 ± 23.1; all p < 0.001). Following completion of ADAPT, participants demonstrated significant improvements in knowledge (58.0 ± 19.9 vs. 77.7 ± 15.9, p < 0.001) and self-reported practice (36.9 ± 24.3 vs. 71.0 ± 20.2, p < 0.001). All participants (100%) and 99% of participants agreed that the course improved their clinical knowledge and practice, respectively.

CONCLUSIONS

ADAPT, an intensive drug allergy educational course was effective in improving drug allergy knowledge and practice for non-specialists. Further longitudinal studies are required to evaluate long-term impact.

Leveraging Quality Improvement Tools to Improve Administration of First-line Surgical Antibiotic Prophylaxis in Patients Labeled as Penicillin Allergic

Introduction

A reported penicillin allergy reduces the likelihood that the patient will receive first-line surgical antibiotic prophylaxis (SAP), which can increase the risk of developing a surgical site infection (SSI). This project aimed to increase the use of first-line SAP agents in orthopedic and pediatric surgery patients with a reported penicillin allergy.

Methods

The Institute for Healthcare Improvement quality improvement methodology was followed. Key drivers included patient and family awareness of true penicillin allergies, standardization for ordering antibiotics, staff buy-in, electronic medical record utilization, and staff comfort with ordering first-line SAP. Initial plan-do-study-act cycles focused on provider education. Subsequent plan-do-study-act cycles focused on the antibiotic delivery process, antibiotic selection, screening tool development for severe delayed hypersensitivity reactions, education, and data transparency. The outcome measure was the percentage of orthopedic and pediatric surgery patients with a reported penicillin allergy that received first-line SAP per month.

Results

Since the start of the project in December 2022, there were 2 statistically significant changes in the outcome measure's mean, shifting the mean from 25% to 84% in orthopedic and pediatric surgery patients with a reported penicillin allergy who received first-line SAP. There were no adverse medication reactions and no statistically significant change in SSIs.

Conclusions

The mean has been at 84% for 9 months showing a sustainable process and culture change regarding first-line SAP usage for orthopedic and pediatric surgery patients. This was achieved through targeting the antibiotic delivery processes without relying on hard stops within the medical record.

Comparing pharmacists versus allergists in low-risk penicillin allergy delabelling: The Hong Kong Penicillin Allergy Pharmacist Initiative (HK-PAPI)

Background

Mislabelled penicillin allergies are associated with a myriad of adverse outcomes and development of anti-microbial resistance. With the overwhelming need for specialist allergy services, pharmacist initiatives such as the Hong Kong Penicillin Allergy Pharmacist Initiative (HK-PAPI) have been advocated. However, evidence of their effectiveness, safety and impact on health-related quality-of-life (HR-QoL) are lacking.To assess and compare the effectiveness, safety and improvements on HR-QoL of pharmacists vs allergists in a pilot low-risk penicillin allergy delabelling initiative.

Methods

All adult patients referred for low-risk penicillin allergy were randomized and evaluated by either pharmacists or allergists in a 1:3 ratio. Outcomes and changes in Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q) scores were compared.

Results

Of 323 patients referred, 96.3% (311/323) completed penicillin allergy evaluation (pharmacists: 83 [24.3%] vs allergists: 228 [66.7%]). Overall, 93.6% (291/311) were delabelled with no difference between evaluations by pharmacists and allergists (92.8% vs 93.9%, p = 0.729). There were no severe or systemic reactions in either cohort. Patients evaluated by either pharmacists (43.4 [SD:29.1] to 10.5 [SD:5.93], p < 0.001) or allergists (37.2 [SD:22.2] to 29.1 [SD:22.4], p < 0.001) reported improved HR-QoL as reflected by DrHy-Q scores. However, absolute changes in DrHy-Q scores were significantly greater among patients evaluated by pharmacists compared to those by allergists (-24.6 [SD:25.1] vs -9.19 [SD:13.7], p < 0.001).

Conclusions

Evaluations and delabelling by pharmacists (vs allergists) were comparably effective and safe among patients with low-risk penicillin allergy. Moreover, patients evaluated by pharmacists even reported significantly greater improvements in HR-QoL, highlighting the potential of multidisciplinary allergy initiatives.

Prospective, Multicenter, Head-to-Head Comparison Between Allergists Versus Nonallergists in Low-Risk Penicillin Allergy Delabeling: Effectiveness, Safety, and Quality of Life (HK-DADI2)

BACKGROUND

Penicillin "allergy" labels are prevalent but frequently misdiagnosed. Mislabelled allergies are associated with adverse outcomes and increased antimicrobial resistance. With an urgent need to delabel the overwhelming number of mislabeled allergies, nonallergist evaluations have been advocated for low-risk individuals. Despite growing interest in non-allergist-led initiatives, evidence on their effectiveness, safety, and impact by direct comparisons is lacking.

OBJECTIVE

To assess the comparative outcomes of penicillin allergy evaluations conducted by allergists versus nonallergists.

METHODS

A prospective, multicenter, pragmatic study was conducted at 4 tertiary hospitals (1 allergist- vs 3 non-allergist-led) for low-risk penicillin allergy patients in Hong Kong-the Hong Kong Drug Allergy Delabelling Initiative 2 (HK-DADI2).

RESULTS

Among 228 low-risk patients who underwent testing (32.9% by allergists, 67.1% by nonallergists), only 14 (6.1%) had positive penicillin allergy testing results. Delabeling rates (94.1% vs 93.3%; P = .777), positive skin test results (2.6% vs 2.7%; P > .99), and drug provocation test results (3.3% vs 2.7%; P = 1.000) were similar between allergists and nonallergists. There were no systemic reactions in either cohort. All patients had significant improvements in health-related quality of life (Drug Hypersensitivity Quality of Life Questionnaire scores -5.00 vs -8.33; P = .072). Nonallergist evaluations had shorter waiting times (0.57 vs 15.7 months; P < .001), whereas allergists required fewer consultations with higher rate of completing evaluations within a single visit (odds ratio, 0.04; P < .001).

CONCLUSIONS

With training and support, nonallergists can independently evaluate low-risk penicillin allergies. Compared with allergists, evaluation of low-risk penicillin allergy by nonallergists can be comparably effective, safe, and impactful on quality of life. More multidisciplinary partnerships to empower nonallergists to conduct allergy evaluations should be encouraged.

Low-risk penicillin allergy delabeling: a scoping review of direct oral challenge practice, implementation, and multi-disciplinary approaches

INTRODUCTION

Penicillin allergy is common, and there is increased clinician interest in direct oral challenge (DOC) as a testing strategy for low-risk penicillin allergy. To aid wider implementation of DOC, consensus definitions of low-risk penicillin allergy phenotypes, and standardized approaches to assessment, DOC procedures, and evaluation, are required.

AREAS COVERED

This review systematically reviews studies that have utilized penicillin DOC in healthcare settings to identify heterogeneity in implementation approaches and synthesize low-risk definitions, procedures, and evaluation.

EXPERT OPINION

Opportunity exists to standardize penicillin DOC procedures in patients with a low-risk penicillin allergy to optimize antimicrobial prescribing and reduce the burden of penicillin allergy. Standardizing the definitions of 'low-risk' and 'positive challenge,' and improving the evaluation of patient safety, alongside the development of a unified approach to the structure of undertaking an oral challenge, is likely to increase uptake and confidence among non-allergist clinicians.

A new clinical opportunity: Rechallenging penicillin allergy in an outpatient pharmacy

In the United States, approximately 27 million people have a documented penicillin allergy, but 90% of the allergies are falsely labeled. By rechallenging suspected allergies, a pharmacist can optimize patient care, fulfill antimicrobial stewardship objectives, and educate patients on true allergies. We suggest a protocol that allows pharmacists to investigate the presence of an allergy and conduct a challenge when indicated. The protocol consists of a patient interview, a risk assessment, an oral rechallenge, and the potential for a skin test. The testing and delabeling of penicillin allergies will enhance the practice of antimicrobial stewardship in the outpatient setting. In the changing landscape of pharmacy, community pharmacists can increase their services and improve patient care. Owing to limited documented experience in the outpatient pharmacy, an opportunity to set the standard and be a leader in the field is present.