The findings, which showed that participants benefited from the antibiotic rifaximin (Xifaxan) even after the course of treatment ended, support previously published research identifying small intestine bacterial overgrowth (SIBO) as a possible cause of the disease.
The randomized, double blind study involved 87 patients either treated with rifaximin or placebo. Those on the rifaximin experienced a 37% overall improvement of their irritable bowel syndrome (IBS) symptoms as compared to 23% on the placebo. Among study subjects whose primary symptom was diarrhea, those on the antibiotic showed more than twice the improvement of those on the placebo.
Patients received the drug (or placebo) for 10 days and were then followed for a total of 10 weeks. Participants kept a stool diary, took a questionnaire and were given methane breath tests. The positive effects of the drug were shown to continue throughout most of the 10-week study, not just during the actual antibiotic course.
“This study is important as it is the first to show that the use of targeted antibiotics results in a more significant and long-lasting improvement in IBS symptoms,” said Dr Mark Pimentel, first author on the study and director of the GI Motility Program at Cedars-Sinai. “These results clearly show that antibiotics offer a new treatment approach – and a new hope – for people with IBS.”