Rifaximin: a nonsystemic rifamycin antibiotic for gastrointestinal infections.

Use of nonsystemic antimicrobials with activity against enteropathogens is a promising approach for treatment of infectious diarrhea and other nonsystemic gastrointestinal infections. Rifaximin is approved by the US FDA for the treatment of travelers' diarrhea caused by noninvasive strains of Escherichia coli in patients aged 12 years and older, and for the reduction in risk of overt hepatic encephalopathy (HE) recurrence in patients aged 18 years or older. Rifaximin has been available in Italy since 1987 and overall is approved in 33 countries for various conditions, such as acute and chronic infections, bacterial diarrhea, HE, and pre- and postsurgical prophylaxis. There is accumulating evidence on the benefit of rifaximin for nonsystemic gastrointestinal infections. This article will serve as an update on rifaximin. The pharmacology and pharmacodynamics of rifaximin along with an updated review on the bacterial susceptibility to rifaximin will be presented. Finally, clinical trials with rifaximin for nonsystemic gastrointestinal indications will be updated.