D1.48 - Challenging decisions: Feasibility and safety of multiple low-risk drug challenges in a single clinic visit during peri-operative anaphylaxis investigation

During the perioperative period, patients are administered a wide variety of medications, often in short succession, making it difficult to discern the causative agent in the event of anaphylaxis. Investigation involves document review, skin and blood testing, followed by provocation challenges. Traditionally drug provocation has been limited to a single medication per clinic visit, resulting in multiple visits over several months, which is resource intensive, disruptive to patients and can delay further surgery. 

A policy of identifying patients that skin test negative to multiple agents that were of low likihood to be the culprit cause of anaphylaxis was adapted. For select patients multiple provocation tests were performed in one day. If the patient reacted it would necessitate returning for individual challenges as per the traditional approach, however if no reaction then a large burden of investigation has been lifted from both patient and clinical team.

We retrospectively reviewed data from patients attending from March 2023 to September 2024. Patients underwent single or multiple drug challenges based on prior triage of low-risk medications. Outcomes, safety and efficiency metrics, were analysed.

A total 56 patients attended and 36 supervised drug challenges were performed; 64% (23/36) single and 36% (13/36) had multiple agents in one clinic visit. The majority single challenges were negative (87%, 20/23). Similarly, those undergoing multiple-agent challenges (92%, 12/13) had no reaction, one was inconclusive, and there were no severe symptoms.

Multiple low-risk drug challenges in a single clinic visit were demonstrated to be safe and effective, resulting in reduced patient attendances and increased clinic efficiency. This approach provides reassurance to patients and clinicians, facilitating access to surgical procedures. Further data collection is ongoing to refine patient selection for multi-drug challenges. This study highlight the need for updated clinical guidelines to support multiple drug challenge approach.