Prophylactic intravenous ondansetron reduces the incidence of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery

Pruritus is a common side effect of intrathecal morphine injection for post -operative pain control. Its incidence is especially high in patients under going cesarean delivery. We investigated the effectiveness of ondansetron i n preventing intrathecal morphine-induced pruritus in such patients. We inc luded 60 consecutive nonbreastfeeding women who were scheduled for elective cesarean delivery. After the administration of spinal anesthesia with bupi vacaine and intrathecal morphine 0.15 mg injection, the patients were rando mly divided into three groups. Group 1 received placebo (normal saline) IV injection, Group 2 diphenhydramine 30 mg IV injection, and Group 3 ondanset ron 0.1 mg/kg IV injection. The incidence of pruritus was significantly low er in the ondansetron group (25%) when compared with that in the placebo gr oup (85%) and in the diphenhydramine group (80%) (both P < 0.05). The posto perative pain score and time to flatus passage were not significantly diffe rent among the three groups. There were no headache or extrapyramidal signs associated with ondansetron use. In conclusion, ondansetron prophylaxis si gnificantly reduced the incidence of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery.