Antiemetic prophylaxis in cardiac surgery: comparison of metoclopramide and ondansetron.

We have compared the effectiveness of ondansetron (115 patients) and metoclopramide (101 patients) for prevention of postoperative nausea and vomiting in patients undergoing cardiac surgery involving cardiopulmonary bypass. In a prospective, randomized, controlled, double-blind study, patients received oral ondansetron 16 mg or oral metoclopramide 10 mg, 1-2 h before surgery. Anaesthesia was not standardized. Assessments of the severity of nausea and occurrence of vomiting were made at intervals after extubation and until discharge from the intensive care, or for a total of 24 h. Compared with the metoclopramide group, the ondansetron group had a higher incidence of nausea (49.6% vs 33.7%; P < 0.05) and vomiting (42.6% vs 24.8%; P < 0.01). There was no difference between groups in the number of patients who accepted postoperative antiemetics (ondansetron 43.4% vs metoclopramide 32.6%) and there was no difference in the incidence of symptoms of moderate or severe nausea.