PROPHYLACTIC ORAL DOLASETRON MESYLATE REDUCES NAUSEA AND VOMITING AFTER ABDOMINAL HYSTERECTOMY

Purpose: The incidence of postoperative nausea and vomiting (PONV) var ies from 50% to 75% after gynaecological surgery under general anaesth esia. This study evaluates the dose-response relationships, safety, an d efficacy of the new 5-HT3 antagonist, dolasetron mesylate, in the pr evention of PONV in women undergoing total abdominal hysterectomy (TAH ). Methods: Three hundred and seventy four women scheduled for TAH und er general anaesthesia were studied at 13 Canadian centres. Patients r eceived in a randomized, double-blind manner 25, 50, 100, or 200 mg do lasetron or place bo po one to two hours before induction of anaesthes ia. The anesthetic protocol was standardized. Efficacy was evaluated f or 24 hr after surgery by comparing the number of emetic episodes, adm inistration of rescue medication, severity of nausea, and patient sati sfaction. Results: Analysis of complete response (no emetic episodes a nd no-rescue for 24 hr) revealed a linear dose-response relationship a cross dolasetron groups (P < 0.002). Dolasetron 100 mg (P < 0.003) and 200 mg (P < 0.01) were superior to placebo. The percentage of patient s with no emetic episodes increased from 29.3% (placebo) to 54.1% (100 mg). Subgroup analysis revealed ASA status (I>II), previous history o f PONV, previous history of motion sickness, and total morphine dose ( > 55 mg associated with less PONV than < 55 mg) influenced the inciden ce of emetic symptoms, but did not alter the results of the primary an alysis. Conclusion: Prophylactic dolasetron (100 mg and 200 ng) reduce s the incidence of PONV in patients having total abdominal hysterectom y.