A non absorbable antibiotic which stays in the gut has been found to be an effective long-term treatment for irritable bowel syndrome (IBS) according to researchers at Cedars-Sinai Medical Center.
The study has been published in the October 17 issue of the Annals of Internal Medicine It is the first to demonstrate benefits from antibiotic use even after end of the course of treatment has ended. This study has supported previously published research that identified small intestine bacterial overgrowth as a cause of the disease.
This study was a randomized, double-blind, placebo-controlled study involving 87 participants, all of whom met specific multinational guidelines for diagnosis of IBS. They received 400 mg of the antibiotic rifaximin three times a day for 10 days or a placebo.
The participants were required to complete an extensive symptom questionnaire at the start of the study and then weekly for 10 weeks following treatment. The questionnaire measured the severity of nine symptoms (abdominal pain, constipation, diarrhea, urgency, bloating, sense of incomplete evacuation, incomplete evacuation, mucus, and gas). Patients were also asked to provide a% global improvement from 0 to 100% in their overall IBS symptoms.
The study revealed that rifaximin not only led to significant improvement in global IBS symptoms during the 10 days it was administered, but showed a continuance of the benefit continued for the 10 weeks of follow up when no antibiotic was given, showing sustained benefit.
Mark Pimentel, M.D., director of the GI Motility Program at Cedars-Sinai and the study's principal investigator said, "The fact that the benefit of the targeted antibiotic continued even after it was stopped provides evidence that the antibiotic was acting on a source of the problem: excess bacteria in the gut. This finding offers a new treatment approach -- and a new hope -- for people with IBS."
Irritable Bowel Syndrome affects about 20% of Americans and is one of the top 10 most frequently diagnosed conditions by U.S. physicians. The disorder is characterized by abdominal pain, cramping, bloating and diarrhea and/or constipation and is a long-term condition that usually begins in early adult life. The episodes may be mild or severe and may be exacerbated by stress and is more common in women than in men.
Pimentel said, "While this study being released today demonstrates that the non-absorbed antibiotic rifaximin has great promise in the clinical improvement of IBS, more research is needed. Next steps include multi-center studies to further assess short- and long-term benefits of this drug. Tests comparing rifaximin to other types of antibiotics that have been used to treat the disease should also be conducted."
Treatments for this disease have been mainly focused on reducing its symptoms because researchers are still clueless about its cause. In the Dec 2000 issue of American Journal of Gastroenterology, Pimentel linked bloating, the most common symptom of IBS, to bacterial fermentation by giving lactulose breath tests to participants.
This test monitors the level of hydrogen and methane on the breath and showed evidence that small intestine bacteria overgrowth may be a causative factor in IBS. The current Annals study participants also took the breath tests, which showed similarly increased levels of hydrogen and methane.
Rifaximin is manufactured by Salix Pharmaceuticals, Inc. Funding for the study was also provided by Salix. The discovery related to the use of rifaximin for IBS was made at Cedars-Sinai by Pimentel. Cedars-Sinai holds patent rights to this discovery and has licensed rights to the invention to Salix.