RESUMO
OBJECTIVES: To compare the efficacy of intravenous ondansetron (4 mg, 2 mL) and granisetron (2 mg, 2 mL) for preventing postoperative nausea and vomiting (PONV) in patients during oral and maxillofacial surgical procedures under general anesthesia. MATERIALS AND METHODS: A prospective, randomized, and double blind clinical study was carried out with 60 patients undergoing oral and maxillofacial surgical procedures under general anesthesia. Patients were divided into two groups of 30 individuals each. Approximately two minutes before induction of general anesthesia, each patient received either 4 mg (2 mL) ondansetron or 2 mg (2 mL) granisetron intravenously in a double blind manner. Balanced anesthetic technique was used for all patients. Patients were assessed for episodes of nausea, retching, vomiting, and the need for rescue antiemetic at intervals of 0-2, 3, 6, 12, and 24 hours after surgery. Incidence of complete response and adverse effects were assessed at 24 hours postoperatively. Data was tabulated and subjected to statistical analysis using the chi-square test, unpaired t-test, or the Mann-Whitney U-test as appropriate. A P-value less than 0.05 was considered statistically significant. RESULTS: There was no statistically significant difference between the two groups for incidence of PONV or the need for rescue antiemetic. Both study drugs were well tolerated with minimum adverse effects; the most common adverse effect was headache. The overall incidence of complete response in the granisetron group (86.7%) was significantly higher than the ondansetron group (60.0%). CONCLUSION: Granisetron at an intravenous dose of 2 mg was found to be safe, well tolerated, and more effective by increasing the incidence of complete response compared to 4 mg intravenous ondansetron when used for antiemetic prophylaxis in maxillofacial surgery patients receiving general anesthesia. Benefits of granisetron include high receptor specificity and high potency, which make it a valuable alternative to ondansetron.