Comparing Ondansetron Versus Phenylephrine in Reduce the Incidence of Hypotension After Spinal Anesthesia in Cesarean Section Publisher



Majd MN ; Shamsi A ; Ali Alallo IH ; Parnian M
Source: Journal of Education and Health Promotion Published:2026

Abstract

BACKGROUND: Spinal anesthesia is the method of choice for cesarean section (CS). This method poses risks such as maternal hypotension. Measures such as prescribing appropriate preventative medications can be an important strategy in the prevention and treatment of hypotension in mothers. MATERIALS AND METHODS: This quasi-experimental study was conducted at Arash Hospital, Tehran University of Medical Sciences, on 110 patients undergoing CS under spinal anesthesia. Then, patients who met the necessary conditions were randomly divided into one of two groups: ondansetron (n = 55) and phenylephrine (n = 55). After spinal anesthesia, one group received an intravenous dose of 100 micrograms of phenylephrine and the other group received 4 mg of ondansetron. During the procedure, the patient’s blood pressure and heart rate were measured every 2 minutes for 20 minutes and then every 5 minutes until the end of the procedure. Data were collected using a researcher-made questionnaire that included demographic information. A P value < 0.05 will be considered significant. RESULTS: The mean age of all participants was 30.08 years, with a standard deviation of 5.90 years. Nausea occurred in 21 of the 110 participants (19.09%) during the surgical procedure. It was more common in the phenylephrine group, affecting 14 patients (25.45%), compared to only 7 patients (12.73%) in the ondansetron group (P = 0.089). Vomiting was a relatively rare event, occurring in only 4 participants (3.64%) across both groups. Of these, 3 cases (5.45%) were in the phenylephrine group, while only 1 case (1.82%) occurred in the ondansetron group (P = 0.308). CONCLUSION: The findings revealed that while both agents were effective in managing maternal hemodynamics during surgery, ondansetron was associated with a significantly lower need for repeat antiemetic administration and reduced nausea and vomiting without increasing the risk of hypotension or bradycardia. Therefore, this finding may be useful for clinical practice and further studies. © 2026 Journal of Education and Health Promotion.