Mirtazapine for Postoperative Nausea and Vomiting: Systematic Review, Meta-analysis, and Trial Sequential Analysis.

PURPOSE

Patients rank postoperative nausea and vomiting (PONV) as the most undesirable outcome of anesthesia. Mirtazapine is hypothesized to be effective in PONV prophylaxis via 5HT3 receptor antagonism.

DESIGN

Systematic review and meta-analysis.

METHODS

We identified seven randomized controlled trials by systematically searching electronic databases that compare the efficacy of mirtazapine versus placebo or ondansetron in reducing PONV.

FINDINGS

Mirtazapine reduced PONV overall versus placebo in three studies (risk ratio [RR] = 0.44; 95% confidence interval [CI] 0.32 to 0.62) both on conventional meta-analysis and trial sequential analysis. One study comparing mirtazapine with ondansetron found similar rates of PONV (RR = 0.96; 95% CI 0.48 to 1.94). Mirtazapine reduced preoperative anxiety versus placebo or ondansetron (standardized mean difference -1.4; 95% CI -2.56 to -0.23) but increased sedation (RR = 22.47; 95% CI 5.61 to 89.93). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) quality of evidence was moderate to low.

CONCLUSIONS

This meta-analysis suggests that mirtazapine reduces PONV overall versus placebo. We found evidence of reduction in preoperative anxiety, although mirtazapine increased the risk of sedation.