Granisetron or ondansentron to prevent hypotension after spinal anesthesia for elective cesarean delivery: A randomized placebo-controlled trial

Study objective: This study aimed to compare the effects of high doses of ondansetron and granisetron before spinal anesthesia on hemodynamic parameters in patients undergoing elective cesarean section.

Design: A double-blinded randomized placebo-controlled trial.

Setting: Operating room.

Patients: A total of 120 parturients with term pregnancy undergoing elective cesarean section with combined spinal-epidural anesthesia were included.

Interventions: Three groups (n = 40 for each group) were formed by randomization. Five minutes before the anesthesia procedure, Group I received 8 mg intravenous (IV) ondansetron diluted in 10 ml normal saline, Group II received IV 3 mg granisetron diluted in 10 ml normal saline, and Group III received IV 10 ml normal saline.

Measurements: Following intrathecal drug administration, intraoperative hemodynamic changes were recorded every 2 min for 20 min and then every 5 min until the end of the operation.

Main results: Twenty patients (50%) in Group I, 12 patients (30%) in Group II, and 29 patients (72.5%) in Group III had hypotension requiring treatment with IV ephedrine (P = 0.001). The ephedrine requirement in Group III was significantly higher than in Groups I (P = 0.033) and II (P < 0.001). Also, the ephedrine requirement in Group II was lower than in Group I, but the difference was not statistically significant (P = 0.055). The mean arterial pressure for the three groups differed in the 10th, 18th, and 60th minutes. The number of patients with nausea or vomiting was lower in Groups I and II than in Group III (P < 0.001). At 5 min, the Apgar scores were higher than 8 for all neonates. Postoperative scores for the visual analogue scale were similar for all groups.

Conclusions: It was concluded that prophylactic IV administration of 3 mg of granisetron or 8 mg of ondansetron before spinal anesthesia results in a significantly lower ephedrine requirement compared to placebo.