Fosfomycin-associated adverse events: A disproportionality analysis of the FDA Adverse Event Reporting System

Fosfomycin, with its unique mechanism of action, has emerged as a promising option for clinicians to combat antimicrobial resistance and the limited availability of effective drugs, which has led to an increase in associated adverse events (AEs). This study aims to explore the AEs caused by fosfomycin through data mining of the US FDA Adverse Event Reporting System (FAERS) to inform clinical safety. As revealed by FAERS, the 796 fosfomycin-associated AEs occurred more commonly in females (61.90%), with Italy reporting the highest incidence (32.40%), and have a significant rise with peak years in 2018 and 2019. The analysis revealed that gastrointestinal disorders, injury, poisoning and procedural complications, and skin and subcutaneous tissue disorders were among the most commonly reported system organ classes (SOCs), accounting for 16.29%, 13.50%, and 11.26% of cases, respectively. The median time to onset (TTO) for fosfomycin associated AEs was 2 days, indicating an early failure type distribution. Off-label use, diarrhoea, and nausea were among the top 50 most frequent AEs, with reporting odds ratios (RORs) of 3.39, 3.87, and 1.79, respectively. These findings emphasize the need for careful monitoring of fosfomycin use, particularly among female patients and in high-reporting regions. The unique profile of fosfomycin associated AEs identified in this analysis calls for a reevaluation of existing safety profiles, as it may differ from previous studies and product labeling. Our findings offer important insights for medical and public health fields, and are essential for enhancing pharmacovigilance and refining clinical management.