A randomized, double-blind trial of Granisetron compared with Dexamethasone in preventing Postoperative Nausea and Vomiting after laparoscopic abdominal surgery at a tertiary care hospital

Background: Granisetron is a highly selective and potent 5-HT receptor antagonist acting specifically at 5-HTreceptors on the vagal afferent nerves of the gut. Granisetron leads to irreversible block of 5-HT receptors. This may account for the long duration action of this drug. Purpose: The present randomized, double-blind study was designed to evaluate and compare the effectiveness of long acting drug, Granisetron and Dexamethasone for preventing post-operative nausea and vomiting in patients undergoing laparoscopic abdominal surgery. Methods: In a randomized, double-blind study, 80 inpatients in the age group of 20-60 years, weighing 40-75 kg, belonging to physical status of ASA I and ASA II (American Society of Anaesthesiologists) scheduled for elective laproscopic abdominal surgeries received Granisetron (2.5mg) and Dexamethasone (8 mg) i.v. (n=40 of each) before IV induction agent. The standardized anesthetic included isoflurane and nitrous oxide in oxygen. After surgery all patients were observed for forty-eight hours. The incidence of nausea and vomiting was recorded at 2, 6, 12, 24 and 48 hours after extubation for a period of 48 hours after the surgery by direct questioning to the patient or His/Her attendents. The PONV was defined as the subjective unpleasant sensation associated with awareness of urge to vomit (nausea, vomiting and retching was grouped together). Results: With Granisetronthe incidence of overall PONV during first 24 hr (0-24 hr) was 30% (n=12) and Dexamethasone showed 40% (n=16). The corresponding incidence during the next 24 hr (24-48 hr) after anesthesia was 37.5% (n=15) in Granisetron and in Dexamethasone was 22.5% (n=9). Overall use of rescue medication was 22.5% (n=9) in Granisetron and 42.5% (n=17) in Dexamethasone. There was a significant difference in the use of rescue medications between the two groups (p value<0.05). No clinically important adverse events due to the study drug were observed in any of the groups. Conclusion: In conclusion Granisetron (2.5mg) intravenous was a better agent in decreasing incidence of post-operative nausea and vomiting. The overall requirement of rescue antiemetic was also significantly less when compared with Dexamethasone group.