Postoperative nausea and vomiting (PONV) is a common complaint after strabismus surgery that leads to unpleasantness, increased hospitalisation time and increased costs. In severe cases, it can lead to dehydration, electrolyte disturbances, aspiration, pneumonia, and even sutures opening.This study was conducted to compare the effects of both ondansetron and granisetron on the reduction of PONV after strabismus surgery.This randomised, and the double-blind clinical study was conducted on patients with ASA I and II undergoing strabismus surgery with age over 3 years old in Shafa Hospital, Kerman University of Medical Sciences during 2017 under general anaesthesia. Patients with inclusion criteria were randomly assigned to one of three groups including Ondansetron (A), Granisetron (B) and control group (C). Matching cases and controls on drugs were fully completed. Furthermore, 100 μg/kg of Ondansetron was intravenously injected, followed by injection of 40 μg/kg Granisetron for another intervention group. All patients underwent the same anaesthetic procedure and intravenous injection of drugs during anaesthesia induction. The severity of nausea and vomiting in recovery, 6 and 18 hours after the operation were verified according to the Verbal Rating Scale (VRS). Our data were analysed by Chi-square, ANOVA and TUKEY tests via SPSS version 18.There was no significant difference between the three groups in terms of age and sex. The incidence of postoperative nausea in recovery among three groups of A, B and C was determined to be 15, 7.5 and 37.5%, respectively. No significant difference was found between the two groups A and B (P = 0.68), although there was a significant difference between these two groups and group C (P < 0.05). The incidence of nausea at 6 hours after surgery in groups A, B and C was recorded as 40, 15 and 65% respectively, indicating that the incidence of nausea in group B was significantly lower than the other two groups, while showed a significant difference with group A (P = 0.039) and group C (P < 0.05). Also, the incident of nausea between groups was not statistically significant 18 hours after surgery (P < 0.05). Additionally, no significant difference was found in different groups in terms of vomiting incidence in recovery, 6 and 18 hours after surgery (P < 0.05).Our study suggests that Granisetron is more effective in preventing PONV during 6 hours after the surgery in comparison with Ondansetron which makes it a favourable alternative for preventing PONV.
