Reduction of postoperative nausea and vomiting with granisetron

The antiemetic effects of granisetron, a selective 5-hydroxy-tryptamine type 3 receptor antagonist, on postoperative nausea and vomiting were studied and compared with placebo and metoclopramide in 60 patients undergoing general anaesthesia for major gynaecological surgery. The patients received a single i.v. dose of either granisetron (3 mg, n = 20) metoclopramide (10 mg, n = 20), or placebo (saline, n = 20) immediately after recovery from anaesthesia. The effects were assessed during the first three and the next 21 hr after recovery from anaesthesia by means of a nausea and vomiting score; 0 = no emetic symptoms, 1 = nausea, 2 = vomiting. The mean scores during 0-3 hr were 0.8, 0.1 and 0.1 after administration of placebo, metoclopramide and granisetron, respectively; the corresponding scores during 3-24 hr were 0.6, 0.5 and 0.1. The scores of the metoclopramide and the granisetron groups were different from the placebo group in the first three hours (P < 0.05). Although there were no differences in the scores during 0-3 hr between the metoclopramide and the granisetron groups, there were differences during 3-24 hr (P < 0.05). It is concluded that granisetron is superior to metoclopramide in the long-term prevention of postoperative nausea and vomiting after anaesthesia.