Brand name(s): Xifaxan, Salix

Generic name: Rifaximin

Preparations: tablet

Uses for IBS:
Xifaxan, or rifaximin, is an antibiotic used to treat travelers’ diarrhea caused by the bacteria Escherichia coli in adults and children over 12 years of age and older. Some experts believe that bacterial overgrowth (possibly E. coli) may cause IBS, which may explain why Xifaxan helps to relieve symptoms of diarrhea-predominant IBS in several clinical studies. A reduction of diarrhea, abdominal bloating, and flatulence occurs after its use. Xifaxan has also been used to treat hepatic encephalopathy with cirrhosis

Xifaxan acts to inhibit E. coli in the gut by blocking its RNA synthesis. Clinical trials have shown that it is effective in reducing watery stools within two days and a cure of travelers’ diarrhea after 3 or more days of treatment. Xifaxan should not be used to treat diarrhea associated with bloody stools or fever, or diarrhea caused by pathogens other than E. coli.

Xifaxan is taken orally however it is poorly absorbed by the GI tract. Less than 0.4% is absorbed, and it is completely excreted unchanged in the feces.

Xifaxan should not be taken by those who have had an allergic reaction or who have known hypersensitivities. Contraindications to Xifaxan include bloody diarrhea, fever, and Pseudomembranous Enterocolitis. Safety in children less than 12 years old has not been tested, and pregnant, lactating women, and the elderly should use xifaxan with precaution.

Adverse Effects
The most frequent adverse effects for Xifaxan include abdominal pain with cramps, fecal urgency, flatulence, and headaches. Less frequent adverse events include abdominal herniation, constipation, altered taste, nausea, a feeling of incomplete defecation, and vomiting.