Irritable Bowel Syndrome (IBS) has always been a bit of a mystery. The disorder, which affects between 10 and 20% of the population, causes diarrhea, constipation and abdominal pain. Everything from food allergies to stress, hormonal changes and a host of other potential causes have been linked to the disease, but doctors have not been able to identify a clear cause — and, as a result, there is no uniformly effective treatment.
Now, researchers from several university hospitals, lead by Dr. Mark Pimentel of Cedars-Sinai Medical Center in Los Angeles believe they are closer to understanding the root cause of IBS, thanks to an antibiotic that managed to alleviate symptoms for 41% of the patients who took it in a clinical trial. Though doctors have found success with antibiotics in the past, this new study provides additional evidence that the culprit for IBS may be a bacterial infection. (More on Time.com: 5 Ways to Improve Your Diet on the Cheap)
In two identical clinical trials, the results of which were published on Jan. 6 in the New England Journal of Medicine, researchers gave 1,258 IBS patients a two week course of thrice-daily doses of either an antibiotic called rifaximin or a placebo. They evaluated the patients after an additional 10 week period and found that 41% of those given the rifaximin reported significant relief of IBS symptoms for at half a month after treatment. While 32% of the placebo group also reported relief of symptoms, the success of the antibiotic is still significant.
The Los Angeles Times reported that rifaximin is an ideal medication for the disorder:
The drug used in the trials, rifaximin, “has the potential to provide a welcome addition to the limited armamentarium of agents that are available to treat IBS,” Dr. Jan Tack of the University of Leuven in Belgium wrote in an editorial accompanying the report.
Rifaximin, which is already approved to treat travelers’ diarrhea and a liver condition called hepatic encephalopathy, is an appealing antibiotic for the purpose, Tack said, because it does not leave the gut and get into the general circulation, does not appear to promote resistance and has few, if any, side effects.
It’s important to note that none of the participants in this trial suffered from constipation, though the same research team is currently conducting a clinical trial with IBS patients with that symptom. (More on Time.com: Is the Economy Making You Fat?)
It’s also worth noting that the the study was funded by Salix Pharmaceuticals, the maker of rifaximin. For more, read the full study here.