Authors (including presenting author) :
Wong VKC (1), Chan CC (1), Li AWT (1), Hooi JKY (2), Chu GKH (2), Wong JCY (2), Mak RWM (1), Chui WCM (1), Li PH (2) , Ho CTK (3), Lau CS (2)
Affiliation :
1 Department of Pharmacy, Queen Mary Hospital, Hong Kong 2 Division of Rheumatology and Clinical Immunology, Department of Medicine, Queen Mary Hospital, Hong Kong 3 Department of Medicine, Tung Wah Hospital, Hong Kong
Introduction :
Penicillins are the most commonly prescribed class of antibiotics and serve as first line therapy for numerous acute infections. Meanwhile, penicillin allergy is also the most commonly reported drug allergy. Nevertheless, more than 95% of patients labelled with penicillin allergy ultimately are able to tolerate penicillins. Incorrect allergy labels bring significant negative impacts on clinical outcomes. Removal or modification of penicillin allergy labels reduces second-line antibiotic use, acquisition of multi-resistant organisms, prolonged hospitalizations and readmissions. However, due to the tremendously increasing new cases, the waiting time for a routine penicillin allergy consultation at Queen Mary Hospital was over 7 years. To reduce waiting time, Clinical Pharmacists were trained to perform penicillin allergy delabelling service under the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI).
Objectives :
This pilot study aims to assess the effectiveness and safety of a Pharmacist-led, protocol-driven penicillin allergy delabelling service.
Methodology :
From February 2022 to November 2022 (10 months), referrals of suspected penicillin allergy cases from various clusters or private sectors to QMH Allergists were further referred to the pilot Pharmacist-led allergy de-labelling service. Enrolled patients received clinical assessment of their true allergy status by Pharmacists and were stratified into various risk categories. Low-risk patients would then receive Skin Prick Test, Intradermal Skin Test (IDT), Patch Test (PT), or Drug Provocation Test (DPT) by Pharmacists according to the HK-DADI protocol. The results were then evaluated by Pharmacists in clinic. Those who passed the tests would have their allergy status delabelled by Allergist subsequently. The impact on their quality of life by the delabelling service was evaluated by performing questionnaires before and after the skin tests.
Result & Outcome :
Of 66 patients recruited, the median years of allergy label per patient is 12. After the first screening, 18 patients refused for further testing and 7 were excluded due to their high risk status.The median time from the date of referral to the first consultation is 55 days compared with 6 years as per usual waiting time. 41 patients (both low risk and non-low risk referrals) have been successfully delabelled. Only one had a positive drug challenge with minimal reaction and did not require hospitalization. Among those completed questionnaires, their quality of life were all improved with average score reduction by 51.3%. Our study demonstrates that penicillin allergy de-labelling by Pharmacist is practical and safe. Clinical outcomes of the patients were improved by increasing choice of antibiotics while the waiting time from referral to delabelling was shortened, which altogether can translate into considerable financial savings and improvement in patient care.
