Good news for irritable bowel syndrome (IBS) sufferers: a new antibiotic may bring symptom relief for up to two months after the initial treatment. But more research will be needed to determine just how long-term the effects actually are, or whether additional treatments are necessary.
While the researchers aren’t exactly clear on how the drug is exerting its effects, what is clear is that it’s working on the underlying cause of IBS, rather than just the symptoms, which is all that current treatments target.
Irritable bowel syndrome affects about 1 in 5 people in the U.S., and is characterized by bloating, abdominal discomfort and cramping, diarrhea, and/or constipation. For many people, "lifestyle" remedies like dietary changes, fiber supplements, and stress management are effective, but for others, additional treatments like prescription medications may be necessary. And they don’t always work.
It’s believed that IBS may be due, in part, to an upset in the gut’s natural balance of microorganisms. According to the study’s background information, earlier antibiotics have born mixed results, some with too many side effects and too little relief from symptoms. The new study looked at the effectiveness of an antibiotic called rifaximin, which bypasses the stomach and targets the gastrointestinal tract specifically.
In the refaximin group, 41% of patients said they had "adequate relief" from their overall symptoms, vs. only 32% of those in the placebo group. When asked specifically about bloating, 40% of people in the rifaximin group said they had relief, vs. 30% in the placebo group. Finally, people in the rifaximin group reported greater improvements in stool consistency and pain than those in the placebo group.
The researchers write that the participants’ symptoms were still relieved up to 10 weeks after the initial treatment. While the researchers aren’t exactly clear on how the drug is exerting its effects, what is clear is that it’s working on the underlying cause of IBS, rather than just the symptoms, which is all that current treatments target. They do point out that some people did not respond to the drug at all, which could suggest that there are alternative causes underlying IBS, which should also to be looked into.
The maker of the drug, Salix Pharamceuticals, which funded the current study, has applied for FDA approval for the drug to treat IBS. Rifaximin is already in use to treat traveler’s diarrhea caused by bacteria.
The study was carried out by researchers at Cedars-Sinai Medical Center in Los Angeles and published in the January 6, 2011 issue of The New England Journal of Medicine.