# Comparison of Ondansetron and Cyclizine for the Management of Postoperative Nausea and Vomiting: A Systematic Review and Meta-Analysis

## TL;DR

This study compares ondansetron and cyclizine for preventing postoperative nausea and vomiting, finding both drugs similarly effective but with cyclizine being more cost-effective.

## Contribution

The study provides a meta-analysis comparing two antiemetics for PONV, highlighting cyclizine's cost-effectiveness and similar efficacy to ondansetron.

## Key findings

- Ondansetron did not significantly reduce PONV incidence compared to cyclizine.
- Cyclizine caused a small delay in time to eye opening but no significant differences in vomiting or rescue antiemetics.
- Low-certainty evidence suggests cyclizine is a reasonable alternative to ondansetron for PONV prevention.

## Abstract

Postoperative nausea and vomiting (PONV) are frequent complications following general anaesthesia, demanding effective and cost-efficient prophylactic strategies. Therefore, this study aimed to assess the comparative efficacy and safety of ondansetron versus cyclizine for PONV prophylaxis in adult surgical patients by adopting a meta-analysis research approach. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were adopted in selecting and screening the studies. A computer-based search of the EMBASE, MEDLINE, CENTRAL, and CINAHL databases was carried out using the last search up to November 2025. The risk of bias of the included randomised controlled trials (RCTs) was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool. A sensitivity analysis was performed to assess robustness, and the certainty of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). All statistical analyses were performed using MetaAnalysisOnline software. Four RCTs involving 433 adult surgical patients were included. Pooled analysis showed that ondansetron did not significantly reduce the incidence of any PONV compared to cyclizine (odds ratio: 0.74, 95% CI: 0.34 to 1.61, p=0.45). Sensitivity analysis confirmed this finding across surgical subtypes. Additionally, there were no significant differences in the incidence of postoperative vomiting (odds ratio: 1.11, 95% CI: 0.61 to 2.02, p=0.74) or the requirement for rescue antiemetics (odds ratio: 1.83, 95% CI: 0.95 to 3.52, p=0.07). However, moderate heterogeneity was observed (I2=68%) for the primary outcome, and cyclizine was associated with a statistically significant, though clinically small, delay in time to eye opening (mean difference: 2.00 min, p<0.001). The overall certainty of evidence was graded as low to very low. Low-certainty evidence indicates that cyclizine is a reasonable approach to preventing PONV, offering comparable efficacy to ondansetron without prolonging hospital discharge times. Due to its cost-effectiveness and potential specific benefit in diagnostic laparoscopy, it might be useful for ambulatory surgical centres aiming to optimize value-based care. However, the efficacy of cyclizine within modern multimodal protocols has not been consistently determined by these monotherapy trials, and long-term assessments of combined antiemetic strategies need to be evaluated.