Study of Efficacy of Ondansetron and Granisetron in Patients Undergoing Surgery Under General Anesthesia

Background: Postoperative nausea and vomiting (PONV) remain prevalent complications following general anaesthesia. Although 5-HT₃ receptor antagonists are widely used for prophylaxis, variability exists in dosing practices and reported efficacy. This study aims to compare the efficacy of ondansetron and granisetron in preventing PONV among patients undergoing surgery under general anaesthesia. Methods: The present study was included 110 patients undergoing elective surgery under general anaesthesia, allocated into Group A (ondansetron 8 mg IV) and Group B (granisetron 3 mg IV), prior to induction. Postoperative nausea was assessed using a visual analogue scale, while vomiting episodes, rescue antiemetic requirements, haemodynamic parameters, and adverse effects were recorded over the first 24 postoperative hours. Results: Baseline demographic and clinical characteristics were comparable between groups. Within the first four postoperative hours, nausea occurred in 52.7% of patients in Group B and 70.9% in Group A; this difference did not reach statistical significance (p = 0.07). Vomiting incidence was similar between the groups (47.3% vs. 43.6%; p = 0.85). No episodes of nausea or vomiting were observed beyond four hours. Adverse effects were mild and comparable in both groups. Conclusion: In this study, no statistically significant difference was detected between ondansetron and granisetron in the prevention of PONV at the doses administered. Although granisetron demonstrated a lower numerical incidence of early postoperative nausea, the study was underpowered to establish equivalence or superiority. These findings should therefore be interpreted cautiously.