Tropisetron for prevention of postoperative nausea and vomiting: a quantitative systematic review

Objective. A quantitative systematic review of randomised controlled trials investigating the efficacy of tropisetron versus placebo to prevent postoperative nausea (PN) and vomiting (PV) as well as PN and/or PV (PONV). Methods. The relevant results for the 24 h postoperative period were extracted from systematically searched studies (MEDLINE, EMBASE, Cochrane-Library, reference lists; last update December 2001). Results. In 19 studies and 22 comparisons, 1,012 patients received a placebo and 1,267 patients tropisetron and the pooled analyses (2-5 mg iv) are presented. The relative risks (RR) for PN, PV and PONV with tropisetron prophylaxis were 0.72 (95%-CI: 0.62-0.83), 0.59 (95%-CI: 0.47-0.73) and 0.70 (95%-CI: 0.62-0.79), respectively. The RR for rescue treatment was 0.63 (95%-CI: 0.54-0.74). The RR in children for a variable dose of 0.1-0.2 mgxkg(-1) was 0.49 (95%-CI: 0.38-0.63),0.49 (95%-CI: 0.38-0.63) and 0.32 (95%-CI: 0.15-0.70) for PV, PONV and rescue treatment, respectively. Restricting the analysis to a predefined control event rate of 40-80% revealed that about 6-7 patients need to be treated with tropisetron for PN to be prevented in 1 patient who would have had PN if all had received a placebo (NNT=6.7; 95%-CI: 4.8-11.1). The corresponding NNT for preventing PV and PONV was 5.0 (95%-CI: 3.6-8.3) and 4.6 (95%-CI: 3.6-6.3), respectively. Conclusion. Tropisetron significantly reduced the incidence of PONV. There is no clear evidence for a dose response between 2 and 5 mg iv. For children a dose of 0.1 mgxkg(-1) of body weight is effective. Sufficient data for the oral application of tropisetron are lacking.