Granisetron in the prevention of nausea and vomiting after middle-ear surgery: a dose-ranging study.

This study was undertaken to determine the minimum effective dose of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for the prevention of postoperative nausea and vomiting (PONV) after middle-ear surgery. In a randomized, double-blind, placebo-controlled trial, 120 women (ASA I) received placebo (saline) or granisetron at three different doses (20 micrograms kg-1, 40 micrograms kg-1, 100 micrograms kg-1) i.v. immediately before the induction of anaesthesia (n = 30 for each group). A standard general anaesthetic technique was used throughout. A complete response, defined as no PONV and no need for another rescue antiemetic during 0-3 h after anaesthesia, occurred in 40%, 43%, 83% and 87% of patients who had received placebo, granisetron 20 micrograms kg-1, granisetron 40 micrograms kg-1 or granisetron 100 micrograms kg-1, respectively; the corresponding incidence during 3-21 h after anaesthesia was 47%, 47%, 87% and 87% (P < 0.05; overall Fisher's exact probability test). Granisetron 40 micrograms kg-1 appears to be the minimum effective dose for preventing PONV in women undergoing middle-ear surgery.