Comparison of ondansetron, metoclopramide and placebo as premedicants to reduce nausea and vomiting after major surgery.

In a randomised, double-blind study, we have compared the incidence of postoperative nausea and vomitting in 124 patients undergoing major lower limb orthopaedic surgery following oral premedication with temazapam and ondansetron 8 mg, metoclopramide 10 mg or placebo. They received a standardised epidural and general anaesthetic. An epidural mixture containing bupivacaine 0.1% and fentanyl 10 mg.ml-1 was infused postoperatively. The occurrence of nausea and vomiting was assessed every 4 h for 24 h. The incidence of vomiting significantly decreased from 55% and 43% in the placebo and metoclopramide groups, respectively, to 26% in the ondansetron group (p = 0.03). The incidence of nausea and vomiting in patients who had previously suffered was also significantly reduced from 67% and 68% in the placebo and metoclopramide groups, respectively, to 29% in the ondansetron group (p = 0.035). We conclude that oral premedication with ondansetron 8 mg was superior to metoclopramide 10 mg and placebo in preventing postoperative nausea and vomiting following major orthopaedic surgery in patients given epidural opioid analgesia.