Introduction & Objective: Post operative nausea and vomiting are more common in females and pregnant patients. Pregnancy induced changes increases the risk of nausea and vomiting and aspiration after general anesthesia. Promethazine a H₁-receptor antagonist is a phenothiazine with prominent antiemetic property. This study was done to determine the effectiveness and side effects of promethazine for prevention of post operative nausea and vomiting in women after general anesthesia for cesarean section .

Materials & Methods: The 101 ASA status I or II women undergoing cesarean section , were prospectively and randomly allocated to receive either 1 cc promethazine (25 mg) (n=51) or
1 cc placebo (n=50) at the induction of anesthesia. Techniques of anesthesia and administered drugs were similar and doses were in the base of body weight in both groups. The occurance of post operative nausea and vomiting and use of drug for treatment and probable side effects of promethazine were recorded blindly in the recovery room and 12-24 hrs post operative period. Demographic data did not have differences between two groups.

Results: The incidence of post operative nausea and vomiting was identical in two groups and had not meaningful difference. The score of sedation was increased considerably in promethazine group (P=0.029).

Conclusion: Promethazine did not significantly decreased post operative nausea and vomiting versus placebo (P=1 , P=0.67).