Biologic properties and clinical uses of rifaximin.

Rifaximin is increasingly being used to treat acute and chronic gastrointestinal infections and disorders. The drug exerts its beneficial effect through a variety of gut-selective mechanisms involving the host intestinal microbiota. Abstracts of all publications listed in PubMed on the topic of rifaximin are reviewed to determine their potential value in the understanding of mechanisms of rifaximin activity. The author's extensive file on the drug is also used in the review. Rifaximin inhibits a broad spectrum of bacteria in the bile-rich small bowel and susceptible bacteria in the aqueous colon, and alters microbial virulence and epithelial cell function. The different mechanisms of action of rifaximin potentially explain the use of the drug in widely varied diseases and syndromes.