Five studies were included in the review (1,803 participants). Two studies appeared to be subsets of the same population. All studies reported low risks of bias for sequence generation, allocation concealment, blinding and incomplete outcome data. One study reported high risk of bias for selective outcome reporting and one study for other source of bias. Follow-up periods ranged from 10 days to 12 weeks.
Compared to placebo, rifaximin was associated with a significant improvement in global IBS symptoms (OR 1.57, 95% CI 1.22 to 2.01; Ι²=26%; five RCTs; therapeutic gain 9.8%; NNT=10.2) and bloating (OR 1.55, 95% CI 1.23 to 1.96; Ι²=22.9%; four studies; therapeutic gain 9.9%; NNT=10.1). The authors reported that there was no evidence of publication bias.
A summary of odds ratios adjusted for different covariance across studies was reported.
Four studies reported adverse effects data. The authors reported that no significant differences were found between treatment and placebo group. The most frequently reported adverse effects were headache, upper respiratory infection, nausea, nasopharyngitis, diarrhoea and abdominal pain.