[15] A total of 502 patients were included Screening Library cell line in the four trials comparing rifaximin with placebo for prevention of TD (Figure 2).[15-18] One-hundred forty-two patients developed TD of which 41 were in the rifaximin group and 101 were in placebo group. The included trials were homogeneous (test for heterogeneity: p = 0.16, I2 = 42%), and the incidence of TD was significantly different between the rifaximin group and the placebo group (RR: 0.41, 95% CI: 0.30–0.56, p < 0.00001). NNT was four, which implied that four patients must receive rifaximin to avoid one case of TD. Seventy two of 404 patients in three

trials required antibiotic treatment for TD, 16 in the rifaximin group and 56 in the placebo group.[15, 18, 19] The included trials were not homogeneous (heterogeneity test: p = 0.11, I2 = 55%) so a fixed model was applied. The incidence of antibiotic treatment was significantly different between the rifaximin group and the placebo group (RR: 0.30, 95% CI: 0.18–0.49, p < 0.00001). NNT was five, which implied that one patient in every five would avoid

antibiotic treatment for TD. There were 197 patients involved in three trials comparing rifaximin with placebo in whom the incidence of MD could be evaluated.[15, 17, 18] The included trials were homogeneous (heterogeneity test: p = 0.25, I2 = 28%). Rifaximin was not associated BMN 673 in vitro with significantly reduced incidence of MD (RR: 1.11, 95% CI: 0.78–1.59,

p = 0.55). There were 153 participants involved in two trials comparing rifaximin with placebo, reporting the incidence of TD in the third week after drug withdrawal.[16, 17] After eliminating the first 2 weeks of data regarding diarrhea, the data were not homogeneous (heterogeneity test: p = 0.97, I2 = 0%). There was no significant difference (p = 0.47) in the incidence of TD in the third week after drug withdrawal between the two groups. Enterotoxigenic E. coli was the major cause of diarrhea and MD during the 2 weeks of drug administration.[16, 18] There was no significant CYTH4 difference between the rifaximin group and the placebo group in TD associated with diarrheagenic E. coli (ETEC or EAEC) (RR: 0.52, 95% CI: 0.24–1.09, p = 0.08). There was significant difference between the two groups in the incidence of unidentified pathogens associated with TD (RR: 0.37, 95% CI: 0.19–0.69, p = 0.002).[16, 17] All trials reported that there were no observed differences in adverse events between the rifaximin group and the placebo group. There was no clinically significant or serious adverse event in any of these studies.[15-18] There were no clinically relevant laboratory abnormalities reported.[16, 18] This meta-analysis shows an advantage of rifaximin over placebo in preventing TD. [Correction added on 3 October 2012, after first online publication: the phrase “protecting TD” was replaced with “preventing TD”.