Reevaluation of the effectiveness of ramosetron for preventing postoperative nausea and vomiting: a systematic review and meta-analysis.

Ramosetron has been shown to have a very strong effect for preventing postoperative nausea and vomiting (PONV) in previous meta-analyses. However, these previous meta-analyses included a number of studies by Fujii et al. which have now been proven to have been fabricated. In the present meta-analysis, we reevaluated the effectiveness of ramosetron in preventing PONV after excluding Fujii et al.'s randomized controlled trials. We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and Web of Science. All double-blind randomized controlled trials that tested the efficacy of ramosetron compared with a placebo or other drugs as a control in the prophylaxis of PONV were considered to be eligible. The first postoperative 24 hours were divided into early (0-6 hours) and late (6-24 hours) time periods, and we collected these data separately. A total of 1372 patients were included in the final analysis. Compared with a placebo, ramosetron reduced the incidence of early postoperative nausea (PON) (relative risk [RR] [95% confidence interval] 0.59 [0.47-0.73]: number needed to treat [NNT] [95% confidence interval] 6.0 [4.3-9.7]), late PON (RR 0.65 [0.49-0.85]: NNT 7.2 [4.6-16.6]), early postoperative vomiting (POV) (RR 0.48 [0.31-0.74]: NNT 14.8 [8.3-70.4]), and late POV (RR 0.50 [0.35-0.73]: NNT 12.3 [7.1-47.6]). Compared with ondansetron, ramosetron reduces early POV (RR 0.50 [0.28-0.90]: NNT 24.1 [10.7-98.0]) and late POV (RR 0.53 [0.34-0.81]: NNT 27.2 [12.0-102.0]) but not PON. Ramosetron has a significant effect for preventing PONV compared with a placebo, but less than that reported in previous analyses. Ramosetron also has statistically significant differences in preventing early and late POV compared with ondansetron, but the clinical significance may be questioned because the NNTs are large.