General Information

Xifaxan (rifaximin) is a semi-synthetic, nonsystemic antibiotic in a 200-mg tablet form. It is approved in 17 countries and was first used in Italy over 17 years ago, with over 500 million tablets prescribed.

Xifaxan is indicated for the treatment of travelers’ diarrhea caused by noninvasive strains of Escherichia coli in patients 12 years old and older.

The recommended dosage of Xifaxan is one 200 mg tablet taken three times a day for three days.

Clinical Results

FDA approval of Xifaxan was based on two randomized, multi-center, double-blind, placebo controlled studies in adult subjects with travelers’ diarrhea. The studies enrolled 320 subjects at multiple sites in Mexico, Peru, India, Guatemala, and Kenya. Subject’s stool specimens were collected before and after the end of treatment to identify enteric pathogens, which was predominantly Escherichia coli. The primary efficacy endpoint was time to last unformed stool (TLUS) which is defined as the time to the last unformed stool passed, after which clinical cure was declared.

Results showed that the duration of diarrhea was significantly shorter in patients treated with rifaximin (32.5 hours) than in the placebo group (58.6 hours). In addition, more subjects treated with rifaximin (99) were classified as being clinical cured than subjects treated with placebo (78). Although rifaximin had microbiologic activity similar to placebo, it demonstrated a clinically significant reduction in duration of diarrhea and a higher clinical cure rate than placebo.

The majority of the rifaximin- treated subjects who had Campylobacter jejuni isolated as a sole pathogen at baseline failed treatment with a clinical cure rate of 23.5% (4/17). These results were no different from placebo and the microbiologic eradication rates for subjects with Campylobacter jejuni isolated at baseline were much lower than the eradication rates seen for Escherichia coli.

Literature References

Di Stefano M, Miceli E, Armellini E, Missanelli A, Corazza GR. Probiotics and functional abdominal bloating. J Clin Gastroenterol. 2004 Jul; 38(6 Suppl): S102-3.

Latella G, Pimpo MT, Sottili S, Zippi M, Viscido A, Chiaramonte M, Frieri G. Rifaximin improves symptoms of acquired uncomplicated diverticular disease of the colon. Int J Colorectal Dis. 2003 Jan; 18(1): 55-62. Epub 2002 May 09.

Steffen R, Sack DA, Riopel L, Jiang ZD, Sturchler M, Ericsson CD, Lowe B, Waiyaki P, White M, DuPont HL. Therapy of travelers' diarrhea with rifaximin on various continents.Am J Gastroenterol. 2003 May; 98(5): 1073-8.