Ondansetron and tropisetron do not prevent intraspinal morphine- and fentanyl-induced pruritus in elective cesarean delivery.

Author(s): Sarvela PJ, Halonen PM, Soikkeli AI, Kainu JP, Korttila KT

Affiliation(s): Department of Anaesthesia and Intensive Care, Helsinki University Central Hospital, Helsinki, Finland.

Publication date & source: 2006-02, Acta Anaesthesiol Scand., 50(2):239-44.

Publication type:

Background: Although intraspinal morphine has been shown to be effective in providing analgesia after cesarean delivery, pruritus as a side-effect remains a common cause of dissatisfaction. The role of ondansetron has been studied in preventing pruritus but the results have been contradictory. Methods: We randomized 98 parturients undergoing elective cesarean section using combined spinal-epidural anesthesia into a double-blinded trial to receive tropisetron 5 mg (T group) or ondansetron 8 mg (O group) or placebo (NaCl group) after delivery, when intrathecal morphine 160 microg and fentanyl 15 microg were used for post-operative pain control. The patients additionally received ketoprofen 300 mg per day. Post-operative itching, nausea and vomiting, sedation and need for rescue analgesics were registered every 3 h up to 24 h, and all patients were interviewed on the first post-operative day. Results: Seventy-six percent of the parturients in the placebo group, 87% in the ondansetron, and 79% in the tropisetron group had itching. The incidence of post-operative nausea and vomiting was 21%, 20% and 11% of the patients in the placebo, ondansetron and tropisetron groups, respectively. Medication for pruritus was needed by 31%, 23% and 39% of the patients in the placebo, ondansetron and tropisetron groups, respectively. In the post-operative questionnaire, the patients reported less post-operative nausea in the tropisetron group than in the placebo group (P < 0.01). Conclusion: Neither ondansetron nor tropisetron prevent itching caused by intrathecal morphine with fentanyl. However, tropisetron reduced post-operative nausea.