Ephedrine Versus Ondansetron in the Prevention of Hypotension During Cesarean Section: A Randomized, Double-Blind, Placebo-Controlled Trial

Background: common side effects of spinal anesthesia for cesarean section (c.s.) include hypotension and bradycardia. ondansetron, a 5ht3 receptor antagonist, has been suggested for prophylactic prevention of spinal induced hypotension (sih) in elective cesarean section. this study compared a traditional vasopressor ephedrine with two doses of 5-ht3 receptor antagonist ondansetron to prevent sih during cesarean section. materials and methods: a total of 168 full‑term parturients undergoing c.s. under spinal anesthesia were included. patients were divided randomly into four groups (ephedrine, 4 mg ondansetron (o4), 8 mg ondansetron (o8), and control group). all patients were monitored for mean blood pressure, heart rate, vasopressor requirement, and side effects. the primary outcome of this study was the incidence of sih in all four groups during the first 60 minutes after spinal anesthesia. results: the incidence of sih was significantly higher in the control group (45.2%) compared to the ephedrine, o4, and o8 groups (19%, 16.7%, and 11.9%, respectively). there were significant differences between the four groups regarding maternal mean arterial pressures during the 1st 60 minutes after spinal anesthesia. no side effects were recorded. conclusion: prophylactic intravenous ondansetron (at a dose of 4mg or 8mg) could be an effective/non-inferior alternative to ephedrine in reducing the incidence of sih and the requirement of vasopressors in parturients undergoing c.s.