Preventive Effect of Hydroxyzine on Postoperative Nausea and Vomiting: A Single-Center, Retrospective, Observational Cohort Study

<b>Background/Objectives:</b> Postoperative nausea and vomiting (PONV) is a common and distressing complication after surgery. Hydroxyzine, an affordable histamine H1 receptor antagonist with anxiolytic, moderate sedative, and antiemetic properties, is often used perioperatively; however, few studies have investigated its effect on PONV. In this study, we examined the efficacy of hydroxyzine in preventing PONV. <b>Methods:</b> This single-center, retrospective, observational cohort study included 647 female patients at risk of PONV between July 2021 and September 2022. The primary endpoint was PONV incidence on the day of surgery, and secondary endpoints included PONV incidence up to postoperative day 2 and emergence time, analyzed using propensity score matching. <b>Results:</b> The patients were categorized into two groups: 71 received hydroxyzine 25 mg (HYD group), and 576 received no prophylactic antiemetic treatment (NOT group). After adjustment for confounders, PONV incidence on the day of surgery was significantly lower in the HYD (n = 69) group compared to the NOT (n = 193) group (34.8% vs. 57.0%, <i>p</i> = 0.002), and similar results were observed up to postoperative day 2 (47.8% vs. 65.3%, <i>p</i> = 0.016). Emergence time did not differ between groups. <b>Conclusions:</b> Prophylactic administration of hydroxyzine could be effective in decreasing PONV incidence, though further randomized controlled trials are warranted to confirm these results.