Background: Postoperative nausea and vomiting (PONV) is a common and distressing complication following surgery, particularly after laparoscopic procedures performed under general anesthesia. Effective prophylactic antiemetic therapy is important for improving patient comfort, facilitating recovery, and reducing postoperative complications. Dexamethasone and ondansetron are commonly used for the prevention of PONV; however, their comparative effectiveness remains of clinical interest.

Materials and Methods: A prospective comparative study was conducted among 50 patients undergoing elective laparoscopic surgery under general anesthesia. Patients were randomly allocated into two groups of 25 patients each. Group D received dexamethasone 8 mg intravenously after induction of anesthesia, while Group O received ondansetron 4 mg intravenously after induction. Patients were monitored during the postoperative period for the incidence and severity of nausea and vomiting, requirement for rescue antiemetic medication, hemodynamic parameters, and adverse effects during the first 24 hours. Statistical significance was considered at a p-value <0.05.

Results: The demographic characteristics of the two groups were comparable, with no statistically significant differences in age, weight, height, BMI, gender, or ASA physical status. The mean duration of surgery was also comparable between Group D and Group O (72.84 ± 14.25 vs. 74.16 ± 13.68 minutes; p=0.74). Heart rate and mean arterial pressure remained comparable between the groups at all observed perioperative time points, indicating similar hemodynamic stability. During the first 24 postoperative hours, PONV occurred in 8 patients (32%) in the dexamethasone group compared with 4 patients (16%) in the ondansetron group (p=0.18). The proportion of patients without PONV was higher in Group O (84%) than in Group D (68%). Rescue antiemetic medication was required in 5 patients (20%) in Group D and 2 patients (8%) in Group O (p=0.22). Adverse effects were infrequent and comparable between the groups, with 88% of patients in each group reporting no adverse effects.

Conclusion: Both dexamethasone 8 mg and ondansetron 4 mg were safe and effective for the prevention of postoperative nausea and vomiting following elective laparoscopic surgery. Ondansetron demonstrated a lower incidence and severity of PONV and a lower requirement for rescue antiemetic therapy compared with dexamethasone; however, these differences were not statistically significant in the present sample. Therefore, ondansetron showed better clinical effectiveness, while both drugs demonstrated favorable safety and comparable perioperative hemodynamic stability.

Keywords: Postoperative nausea and vomiting, PONV, Dexamethasone, Ondansetron, Laparoscopic surgery, General anesthesia, Antiemetic.