Rifaximin in the treatment of infectious diarrhea.

Rifaximin matches the criteria for an ideal agent for the treatment of infectious diarrhea. It has excellent activity against a broad range of enteropathogens. It is nonabsorbable, which may help explain its excellent side effect profile and lack of emergence of resistance because of high stool levels that are not likely to reach subinhibitory levels before the target Gram-negative bacilli are killed. It has shown excellent efficacy in numerous clinical trials of bacterial diarrhea. Because of the lack of systemic absorption and minimal adverse reactions, rifaximin should be useful in treating hosts such as pregnant women in whom the currently favored fluoroquinolones are contraindicated. Uses limited to enteric indications and its inherently low propensity to induce sustainable resistance among Gram-negative flora favor the sustained usefulness of rifaximin in the treatment of enteric infectious syndromes.