Background: Postoperative nausea and vomiting (PONV) are some of the most-common and undesirable adverse effects after surgery performed under general anesthesia. We investigated the prophylactic value of dexamethasone as an alternate to ondansetron or metoclopramide to prevent PONV after gynecologic surgery.
Material/Methods: One hundred sixty ASA I-II patients scheduled for elective gynecologic surgery were enrolled. Before induction of anesthesia, patients were randomly allocated to receive intravenously dexamethasone (8 mg) in group D, ondansetron (4 mg) in group O, metoclopramide (10 mg) in group M, and saline (2 mL) in group P. Total incidence of nausea and vomiting, rescue antiemetic requirement, pain scores, and any adverse effects were recorded at 3 observational periods (0–2 hours, 2–12 hours, and 12–24 hours).
Results: Total rates of PON, POV, and PONV were significantly higher in group P at 0–2 hours and 2–12 hours compared with group D, O, and M (P<.05). There was no difference in PON, POV, and PONV among D, O, and M groups. None of the groups differed in PONV in the subsequent 12–24 hours. Number of patients requiring rescue antiemetic was significantly higher in group P than the other groups at 0–2 hours (10%, 10%, 15%, and 45% in group D, O, M, and P) (P<.05).
Conclusions: Prophylactic IV dexamethasone 8 mg significantly reduces the incidence of PONV in gynecologic surgery. At this dosage, dexamethasone is as effective as ondansetron 4 mg and metoclopramide 10 mg, and is more-effective than placebo.

Keywords: Postoperative Nausea and Vomiting - etiology, Ondansetron - therapeutic use, Hysterectomy, Metoclopramide - therapeutic use, Gynecologic Surgical Procedures - adverse effects, Dexamethasone - therapeutic use, Antiemetics - therapeutic use, young adult