Comparison of ileus risk in selected second-generation antipsychotics based on FAERS database

Second-generation antipsychotics (SGAs) have been developed as an alternative to the first-generation antipsychotics due to their fewer side effects. However, clinical case reports suggested a connection between SGAs and ileus. The aim of this study is to explore the links between ileus and SGAs via a pharmacovigilance analysis. Adverse event reports from January 1st, 2014 to December 31st, 2023 were collected from the U.S. Food and Drug Administration Adverse Event Reporting System database. The demographic characteristics of cases were summarized to perform descriptive analysis. The reaction outcomes, actions taken with the drug, and onset time of ileus, were also extracted and analyzed. In disproportionality analysis, the algorithms of reporting odds ratio (ROR) and information component (IC) were applied for ileus risk signal detection. A total of 419 cases with SGAs-related ileus were obtained from the database. The median age for patients was 58 years (range 6 ~ 94) and the median onset time of ileus was 40 days (range 0 ~ 6070). After excluding reports with incomplete data, a total of 219 cases were identified in reaction outcomes and a total of 179 cases were included in the analysis of actions taken with the drug. A majority of patients reached recovered state (n = 119, 54.34%) in reaction outcomes, and most patients received drug withdrawn (n = 120, 67.04%) in actions taken with the drug. Clozapine showed the strongest risk signal of ileus (n = 131, ROR₀₂₅ = 2.77, IC₀₂₅ = 1.42), whereas this signal was not significant in risperidone (n = 29, ROR₀₂₅ = 0.68, IC₀₂₅ = -0.38). In summary, our data suggested that SGAs administration increased the risk of ileus. These results would provide valuable insight into the prognosis and safe use of SGAs.