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Irritable Bowel Syndrome (IBS) Health Center

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2 Weeks of Antibiotic Therapy Relieves IBS

Study Shows Rifaximin Helps Ease Symptoms of Irritable Bowel Syndrome

Rifaximin for IBS: Study Details continued...

The patients reported on their symptoms and were followed for 10 weeks after the two-week doses.

For the two studies combined, 40.7% of those taking the drug had adequate relief of their symptoms during the first four weeks after treatment, but just 31.7% of those on placebo.

While 40.2% of those on the drug had relief from bloating, 30.3% of those in the placebo group did.

The drug, Pimentel says, "passes through the gut and gets rid of the bacteria in the small bowel that [are believed to] cause the problems."

The studies were funded by Salix Pharmaceuticals Inc., which makes rifaximin. Pimentel serves as a consultant to Salix and serves on its scientific advisory board. He discovered the use of the antibiotic for IBS. Cedars-Sinai holds the patent and has licensed the rights to Salix.

Salix has applied for FDA approval of the drug for the non-constipation form of IBS and IBS-related bloating, says Mike Freeman, company spokesman.

Rifaximin for IBS: Second Opinion

In an editorial published with the study results, Jan Tack, MD, PhD, a professor of medicine at University Hospital of the University of Leuven in Belgium, writes that "The TARGET studies have some attractive findings," including the sustained benefits and short treatment course.

It also seems to relieve the bloating, which he calls one of the most challenging symptoms.

But he has some caveats -- calling for more studies before the drug is widely used.

In an email interview, he says his main concern is antibiotic resistance -- so far not shown to be a problem in research studies -- and that the study follow-up needs to be longer.

"This issue is relatively easy to address with a longer-term follow-up study or a retreatment trial," he tells WebMD.

For now, he suggests that the antibiotic be reserved for those patients in whom overgrowth of the small intestine bacteria has been confirmed, or to limit treatment to a single cycle for those not responding to other medications.

Tack has severed as a scientific adviser to companies evaluating IBS drugs.

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