A pharmacovigilance study of olanzapine/samidorphan based on FDA Adverse Event Reporting System (FAERS)

The olanzapine/samidorphan (OLZ/SAM) combination is being regarded as a new strategy to combat weight gain induced by olanzapine (OLZ), and its safety is of significant concern. Specifically, as samidorphan is an opioid receptor-related drug, issues related to its potential for dependence and withdrawal symptoms deserve attention. This study aims to provide a comprehensive analysis of adverse events (AEs) associated with the OLZ/SAM.

This study is a pharmacovigilance study based on the analysis of reports from the FDA Adverse Event Reporting System (FAERS) utilizing the Openvigil online analysis platform for the period from January 1, 2023, to June 30, 2024. Signal results were reported as Reporting Odds Ratios (ROR) along with 95% confidence intervals. A binary logistic regression model was used to analyze the association between the OLZ/SAM and specific AEs.

This study included 86 reports of AEs associated with the OLZ/SAM and 4,678 reports related to OLZ. In terms of frequency of OLZ/SAM-related AEs, off-label use (N = 12) and drug withdrawal syndrome (N = 11) were reported most frequently. Among various system organ classes, the highest frequency of AEs was observed in neurological disorders (SOC) (N = 23). We identified 15 signals associated with the OLZ/SAM. The results of the stepwise regression analysis indicated that in all models, the OLZ/SAM was significantly associated with drug withdrawal syndrome when compared to OLZ (p < 0.01).

The long-term safety of the OLZ/SAM warrants attention, particularly concerning drug withdrawal syndrome.