The Effects of Different Doses of Intravenous Ondansetron on Hemodynamic Changes and Motor and Sensory Block Induced by Spinal Anesthesia in Women Undergoing Caesarean Section

Background: Spinal anesthesia is a common method used in caesarean section (C- section). One of the common complications of spinal anesthesia is hypotension that is controlled through pharmacotherapy and fluid therapy. This study aimed to evaluate the effects of 4 and 8 mg intravenous (IV) ondansetron on hemodynamic changes and motor and sensory block induced by spinal anesthesia in women undergoing elective C-section. Materials and Methods: This clinical trial included a group of healthy pregnant women (n=96) undergoing elective C-section at the Amiralmomenin Hospital, Zabol, Iran, in 2014. The participants (n=96) were randomly assigned into the following three groups: (i) control group (n=32) receiving IV placebo, (ii) low-dose group (n=32) receiving 4 mg IV ondansetron, and (iii) high-dose group (n=32) receiving 8 mg IV ondansetron. The data were analyzed using SPSS software version 22.0. Analysis of variance (ANOVA), Chi-square test and repeated-measures ANOVA were used to compare the significance of the differences among groups. Results: The findings showed that 8 mg IV ondansetron improved hypotension and nausea when being applied 5 minutes before spinal anesthesia as compared to the low dose (P=0.080) and control (P=0.005) groups, suggesting there is a statistically significant difference in this regard among the groups. Conclusion: An 8-mg single IV dose of ondansetron significantly reduces hypotension induced by anesthesia, use of vasoconstrictors as well as nausea and vomiting before subarachnoid block in women undergoing elective C-section.