RESUMO
Antiemetics currently in use are not totally effective. Serotonin Receptor Antagonists are a new class of antiemetics that have shown promise for the treatment of nausea and vomiting in many situations. This study aims at evaluating the efficacy of Serotonin Receptor Antagonist, Ondansetron, for the prevention of postoperative nausea and vomiting. This randomized, double-blind study compared the efficacy of an intravenous dose of Ondansetron 4 mg. with Metoclopramide 10mg. for the prevention of postoperative nausea and vomiting [PONV] in patients undergoing general anesthesia for open abdominal surgery. A total of 126 patients [63 Ondansetron group, 63 Metoclopramide group], ASA status I-II, aged 18-65 years, were included and received the study medication after the induction of anaesthesia. A standardized anesthetic technique and intraoperative analgesia were used for all the patients. Within a period of 24 hours after the surgery, the following data were gathered and recorded: the proportion of the patients experiencing no emesis or no nausea as well as those who were provided with rescue antiemetic medication, the duration of nausea and the number of emetic episodes. During the overall observation period [i.e. 0-24 hours], more patients who had received Ondansetron had significantly no emetic episodes [87.3%] than those who had received Metoclopramid [73%, P=0.044]. A higher proportion of patients receiving Ondansetron [71.4%] did not experience nausea [Metoclopramide 63.5%, P=0.342]. Fewer patients in the Ondansetron group required rescue medication [P<0.05]. Ondansetron was superior to Metoclopramide for the prevention of vomiting in the first 24 hours after surgery and the total number of emetic episodes was significantly reduced, as compared with Metoclopramide, but no significant differences were observed between Ondansetron and Metoclopramide for either the prevention of nausea or the treatment failure