OPRM1 A118G Polymorphism and Ondansetron Efficacy for Postoperative Nausea and Vomiting in Laparoscopic Gynaecological Surgery: A Retrospective Cohort Study.

BACKGROUND

The OPRM1 A118G polymorphism has been implicated in modulating susceptibility to postoperative nausea and vomiting (PONV). Ondansetron, a 5-HT3 receptor antagonist, is widely utilized for PONV prophylaxis; however, whether its efficacy is influenced by OPRM1 A118G polymorphism remains unclear.

METHODS

We conducted a retrospective cohort study including patients undergoing laparoscopic gynecological surgery between January 2019 and December 2024; propensity score matching was used to adjust for confounders. OPRM1 A118G genotypes (AA, AG, GG) were analyzed through polymerase chain reaction and sequencing. PONV incidence and severity were assessed using the Visual Analog Scale (VAS) at various postoperative time points.

RESULTS

The Ondansetron group had significantly lower PONV incidence within 2 hours (38.82% vs 56.98%, p = 0.0174) and 2 ~ 24 hours (8.24% vs 19.77%, p = 0.0300). The OPRM1 A118G polymorphism was associated with higher PONV risk, particularly in patients with the AG/GG genotypes in the control group. In the Ondansetron group, the association was significant only within 2 hours (p = 0.0460).

CONCLUSION

The OPRM1 A118G polymorphism is associated with an increased risk of early PONV, particularly in patients with the G allele, which has been related to reduced μ-opioid receptor sensitivity and increased opioid requirements, thereby predisposing patients to a higher PONV risk. Ondansetron significantly reduces PONV incidence and severity, especially in patients with higher genetic susceptibility.