Safety evaluation of subcutaneous and intravenous administration of infliximab: a real-world study based on the FAERS database.

Background: Inflammatory Bowel Disease (IBD) is characterized by recurrent flare-ups, significantly impairing patients' long-term quality of life and increasing the risk of complications. As the first chimeric monoclonal antibody targeting tumor necrosis factor-alpha (TNF-α), infliximab blocks TNF-α-mediated inflammatory cascades and has become an important therapeutic agent for moderate-to-severe IBD. Although clinical trials have highlighted its safety and efficacy, real-world data on adverse events (AEs) associated with different administration routes remains limited. This study aims to analyze the U. S. Food and Drug Administration's Adverse Event Reporting System (FAERS) to compare the spectrum and time-to-onset of infliximab-related AEs across different administration routes, following the READUS-PV guidelines. Methods: Data from the FAERS database were analyzed using discriminant and stratified analytical methods, and reporting odds ratio (ROR) methods for comparative analysis, and the Weibull distribution for the time to onset of adverse reaction events analysis. The study examined data from the first quarter of 2014 through the first quarter of 2025 to analyze adverse event signals and the time of occurrence between intravenous and subcutaneous infliximab administration. Results: A total of 178,925 adverse reaction reports associated with infliximab were identified. Among these, 5,144 events were linked to intravenous administration, while 1,084 events were related to subcutaneous administration. The analysis revealed that infection-related adverse reactions were common with both different administration routes of infliximab. Notably, reports of infusion-related reactions were more frequently associated with intravenous administration, while delayed hypersensitivity reactions involving musculoskeletal and connective tissue disorders were more prominently reported in association with subcutaneous administration. Additionally, Weibull distribution analysis indicated a median onset time of 436.5 days for intravenous administration and 376 days for subcutaneous administration. Both routes exhibited early failure signals, suggesting a gradually decreasing risk of AEs over time. Conclusion: AEs and the time of onset vary across different administration routes of infliximab. Consequently, clinicians should consider these differences when selecting the administration route to balance therapeutic efficacy with the risk of adverse reactions.