In two studies involving a total of 1,260 patients with irritable bowel syndrome (IBS) without constipation, researchers found that 550 mg doses of rifaximin taken three times per day for two weeks provides relief of irritable bowel syndrome symptoms such as bloating, abdominal pain, or loose or watery stools. In addition, the researchers from the University of North Carolina, Cedars-Sinai Medical Center, and Salix Pharmaceuticals found that the positive effects of the two-week rifaximin treatment lasted for 10 weeks after patients stopped taking the drug.
According to co-author Yehuda Ringel, M.D., of the University of North Carolina, the benefits of rifaximin treatment found in the studies suggest that irritable bowel syndrome may be caused by bacteria in the gut. Rifaximin treatment alters this bacteria, thus providing relief for patients of irritable bowel syndrome.
In the studies, participants were given either the 550 mg dose of rifaximin or a placebo. Over 40 percent of those who took rifaximin reported adequate relief of all symptoms of irritable bowel syndrome. On the other hand, under 32 percent of patients in the placebo group reported relief.
Correspondingly, about 40 percent of patients in the rifaximin group reported adequate relief of bloating, while about 30 percent in the placebo group reported relief of bloating. Furthermore, patients who took rifaximin also reported more relief of abdominal pain and loose or watery stools, compared to those in the placebo group.
In addition to providing relief of symptoms of irritable bowel syndrome, rifaximin also appears to be very safe.
Researchers at the University of North Carolina are currently trying to further our understanding of how intestinal bacteria can cause gastrointestinal problems such as irritable bowel syndrome.
Irritable bowel syndrome affects an estimated 15.3 million people in the United States, causing approximately 3 million ambulatory care visits, 212,000 hospitalizations, and 20 deaths each year.
The findings of these clinical studies are published in the January 6, 2011 issue of the New England Journal of Medicine.