Background: Antiemetics are highly effective in chemotherapy-induced nausea and vomiting. We utilized Food and Drug Administration Adverse Event Reporting System (FAERS) database to evaluate adverse events (AEs) caused by selected antiemetics commonly used in outpatient oncology practice. Methods: We analyzed the FAERS database to assess the cardiac, gastrointestinal (GI), and hematologic AEs for metoclopramide, olanzapine, ondansetron, and promethazine from 2013 through 2022. The disproportionality signal was analyzed by calculating Reporting Odds Ratio (ROR) with a 95% confidence interval (CI)—considered significant when the lower limit of 95% CI was > 1. Results: A total of 20,302 AEs were identified, out of which 8,135 (40.1%) were cardiac—arrhythmia and QTc prolongation; 8,656 (42.5%) were GI—nausea/vomiting, constipation/diarrhea, abdominal pain/discomfort, and dyspepsia; and 3,511 (17.3%) were hematologic—leukopenia, thrombocytopenia, anemia, and pancytopenia. Compared to other antiemetics, promethazine and olanzapine had higher cardiac and hematologic AEs, respectively, whereas metoclopramide, followed by ondansetron had higher GI AEs (Table). Conclusions: Antiemetics are readily available and effective, yet the preference for a particular drug or drug combination varies. Our study highlights selected antiemetics AEs in order to help individualize treatment for this often challenging and frequently encountered entity.

* Asterisk in the table denotes a positive signal.