Thromboembolic events with olanzapine: a systematic review integrating meta-analysis and FAERS database

Background Olanzapine is an atypical antipsychotic used to treat schizophrenia and manic episodes. Its potential thromboembolic risk has been reported, but the evidence remains controversial. This study aimed to comprehensively evaluate the association between olanzapine and pulmonary embolism (PE) and venous thromboembolism (VTE). Methods This study combined meta-analysis and signal mining from the FDA Adverse Event Reporting System (FAERS) database to assess the association between olanzapine and pulmonary embolism (PE) and venous thromboembolism (VTE). Results From 55,905 olanzapine-related adverse event reports in the Faers database, 1,233 significant signals were identified, including serious adverse events not fully documented on the drug label, such as pulmonary embolism and venous embolism. A meta-analysis of eight studies showed that olanzapine use significantly increased the risk of VTE and pulmonary embolism (OR = 2.07, 95% CI: 1.37–3.14, P = 0.0006). Conclusion These findings suggest that olanzapine is associated with an increased risk of thromboembolic events; therefore, enhanced clinical surveillance and further investigation into its safety are necessary. Systematic Review Registration https://www.crd.york.ac.uk/prospero/ , identifier CRD420251003254.