Background and purpose: Fentanyl is commonly used for spinal analgesia during labor, but it is associated with high incidence of pruritus. This study was performed to evaluate the effect of intravenous injection of prophylactic granisetron on the incidence and severity of pruritus induced by intrathecal fentanyl among the parturients undergoing cesarean section under spinal anesthesia.
Materials and methods: This double-blind clinical trial was performed in 136 ASA I or II (based on the American Society of Anesthesiology Classification) women undergoing elective caesarean section under spinal anesthesia with 0.5% hyperbaric bupivacaine (10 mg) and fentanyl (25 µg). After parturition and clamping of the umbilical cord, the subjects were randomized to receive 1 mg of IV granisetron (group G) or 0.9% saline (group S). To compare the incidence and severity of pruritus between the two groups, Fisher’s exact test and t-test were performed, respectively, using SPSS version 21.
Results: The overall incidence of pruritus was 3.74% (group S=5.76% and group G=1.72%). In the G group, the incidence of pruritus was significantly different and lower in recovery (P=0.01). There were significant differences between the groups in terms of severity of pruritus during surgery, which was lower in the G group (P=0.005).
Conclusion: This study showed that granisetron as the 5-hydroxytryptamine (serotonin) subtype 3 antagonists may reduce the incidence and severity of pruritus induced by intrathecal opioid.