Background and objective In a randomized, placebo-controlled, double-blind trial, we compared the efficacy of dolasetron and metoclopramide in preventing postoperative nausea and vomiting in women undergoing hysterectomy.

Methods Patients were allocated randomly to one of three groups: group A (n =50) received 50 mg dolasetron orally, group B (n =50) received 20 mg metoclopramide intravenously and placebo orally, group C (n =50) received placebo orally. If patients complained of retching or vomiting, or if patients demanded an antiemetic, 1.25 mg droperidol was administrated intravenously. To quantify postoperative nausea and vomiting the following score was used: 0 =no nausea, 1 =nausea, 2 =retching, 3 =single vomiting, 4 =multiple vomiting. The Raatz test was used to analyse postoperative nausea and vomiting (PONV) scores.

Results Dolasetron reduced the postoperative nausea and vomiting score significantly (P <0.02 vs. metoclopramide; P <0.0001 vs. placebo). Metoclopramide also reduced the postoperative nausea and vomiting score (P <0.02 vs. placebo). Fisher's exact test showed a significant reduction of vomiting in the dolasetron group compared with metoclo-pramide-treated patients (P <0.007) and placebo-treated patients (P <0.000006) and a significantly lower rate of nausea in comparison to the placebo group (P <0.009). There were no significant differences between the metoclopramide and the placebo groups (in Fisher's exact test). The use of postoperative droperidol per patient was significantly lower in the dolasetron group (P <0.04 vs. metoclopramide; P <0.0001 vs. placebo) than in the metoclopramide (P <0.02 vs. placebo) and in the placebo groups.

Conclusions Oral dolasetron is more effective than either metoclopramide given intravenously or placebo for preventing vomiting after hysterectomy. It also was significantly superior to either metoclopramide or placebo concerning the PONV score and the need for droperidol rescue.