4CPS-192 Transforming drug shortages into opportunities for optimal use of aztreonam

<h3>Background and Importance</h3> Aztreonam serves as a valuable alternative for patients with documented beta-lactam hypersensitivity. However, many patients are incorrectly labelled as beta-lactam allergic, leading to an inappropriate use. Due to the national drug shortage, an opportunity arose to ensure the suitable utilisation of the antibiotic. <h3>Aim and Objectives</h3> The main aim is to develop a utilisation protocol for aztreonam and evaluate the outcomes of that implementation. <h3>Material and Methods</h3> The protocol was developed by a multidisciplinary team, including pharmacists, allergists, infectious disease specialists, and microbiologists. This team established an action plan to evaluate allergy status, identify therapeutic alternatives, and ensure the proper use of aztreonam through centralised preparation carried out by the pharmacy department. The implementation period was from April to August 2024. To assess the impact of the protocol, data of defined daily doses (DDD) were compared with the same period in 2023. Moreover, we evaluated the outcomes of the protocol implementation by identifying patients whose treatments were optimised and whose beta-lactam allergy status was clarified. <h3>Results</h3> During the study period, aztreonam was prescribed to 68 patients; however, only 25 patients (36.7%) ultimately received aztreonam with a consumption of 232.5 DDD. In contrast, the same period in 2023 had 106 patients with aztreonam, resulting in 454.25 DDD. Notably, 76.3% of patients labelled with a beta-lactam allergy had their allergy confirmed by the interdisciplinary team, compared to only 55.7% in the same period of the previous year. Among those patients who did not receive aztreonam, 31 (45.6%) were given alternative therapies to beta-lactams, while eight patients (11.8%) had their false allergy disproven and were switched to other beta-lactams. Additionally, four patients (5.9%) underwent desensitisation to beta-lactams. Within the 25 patients who received aztreonam, the median age was 72 years (IQR 62–93). The main indications were pneumonia (44%), sepsis (20%) and empiric coverage (20%). Five patients (20%) required aztreonam for infections caused by multidrug-resistant <i>K. pneumoniae.</i> The pharmacy department prepared 445 aztreonam admixtures, consisting of 268 of 1g and 177 of 2g. <h3>Conclusion and Relevance</h3> The implementation of the protocol during the shortage effectively reserved aztreonam for patients who needed it and demonstrated how supply crises can enhance antibiotic stewardship through multidisciplinary collaboration. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest