Background and importance An inadequate antimicrobial prescription is often associated with an increase in antimicrobial costs and, as a result, the antimicrobial stewardship programme (ASP) includes an absolute reduction of 9% in antimicrobial costs.

Aim and objectives To describe the economic impact of antimicrobial shortages in a hospital ASP.

Material and methods Descriptive observational study, that included all drug shortage alerts published in the Spanish Agency of Medicines between March 2020 and April 2021.

An analysis was performed for the drug alerts in pharmacological groups J01 (Antibacterials for systemic use) and J02 (Antimycotics for systemic use), and those included in the ASP. Current stock-outs in the hospital, stock-outs periods (days) and therapeutic alternatives (TA) of these drugs were recorded. The expenditure description was performed comparing the antimicrobials affected by stock-outs with the TA, using the ratio cost/defined daily dose (DDD). The incremental expenditure and expenditure proportion of these stock-outs were recorded. The cost and number of DDD were recorded from the FarmaTools computerised physician order entry (CPOE) software.

Results A total of 441 drug shortage alerts were recorded. Of these, 40 were classified into pharmacological groups J01 and J02. 17 of these 40 shortages (42.5%) comprised 8 antimicrobials included in the ASP. No stock-outs were found for 5 of 8 antimicrobials (daptomycin, caspofungin, aztreonam, linezolid and piperacillin/tazobactam), but for 3 of 8 (anidulafungin, voriconazole and ceftolozane/tazobactam) with stock-outs periods of 9, 31 and 108 days, respectively.

The ratio cost/DDD was €52.30 for anidulafungin and €51.01 for the TA (caspofungin), €20.72 for voriconazole and €56.66 for the TA (liposomal amphotericin B) and €264.54 for ceftolozane and tazobactam and €268.38 for the TA (ceftazidime/avibactam). Incremental expenditure was €6409.29, representing 3.2% of the total antimicrobial expenditure (€200 409).

Conclusion and relevance Antimicrobial shortages force the prescription of other drugs for the treatment of infectious diseases, which result in expenditure increases. These problems tend to reduce the impact of the pharmacists’ ASP activity in the hospital, which has been shown to be an effective solution in optimising antimicrobial treatments.

References and/or acknowledgements 1. Karanika S, et al. Systematic review and meta-analysis of clinical and economic outcomes from the implementation of hospital-based antimicrobial stewardship programs. Antimicrob Agents Chemother 2016;60(8):4840–4852.

Conflict of interest No conflict of interest