Background: Common adverse side effects related to the use of neuraxial opioids in the
obstetric population include nausea, vomiting, and pruritus. Serotonin (5-HT3) receptor
antagonists, in particular ondansetron, have been identified as possible antipruritic agents.
It was reported that dexamethasone plus ondansetron is more effective than ondansetron for
prevention of postoperative nausea and vomiting but no additional effect on treating
pruritus.

Objectives: The purpose of this study is to compare the effect of prophylactic ondansetron
versus ondansetron plus dexamethasone after cesarean section on pruritus and postoperative
nausea and vomiting (PONV).

Methods: A prospective randomized double blind study that will be conducted between June 2016
and June 2017. Patients will be randomly allocated into two groups. The first group will
receive 4 mg intravenous (IV) ondansetron while the other group will receive 4 mg IV
ondansetron plus 8 mg dexamethasone.