Antibiotics for IBS

In many countries (not the UK) Rifaximin is licensed for the treatment of non-constipation predominant irritable bowel syndrome. It is thought that the antibiotic may work by altering the bacteria within the colonic microbiome that cause low level inflammation and thence hypersensitivity within the gut. Evidence suggests the antibiotic may reduce flatulence, bloating and abdominal pain. Some individuals require repeated courses, since colonic flora tends to re-establish after a period without treatment.

There is some evidence that a subset of patients diagnosed with irritable bowel syndrome actually have small intestinal bacterial overgrowth. For this patients rifaximin may also be effective.