TOPLINE:

Rifaximin, a topical antibiotic, appeared to be as effective as the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet in managing irritable bowel syndrome (IBS) over 4 weeks, while providing faster symptom relief at 2 weeks and higher adherence to treatment.

METHODOLOGY:

• Rifaximin and the low-FODMAP diet are recommended as second-line therapies for IBS when initial treatments are ineffective, but comparative data on these options are limited.
• Between June 2021 and November 2024, researchers in Malaysia screened and enrolled 100 patients with IBS at a single gastroenterology clinic to compare the efficacy of rifaximin to that of the low-FODMAP diet.
• Participants were randomly assigned to receive 400 mg oral rifaximin three times a day for 2 weeks (n = 50; median age, 38.5 years; 46% women) or to engage in a low-FODMAP diet for 4 week (n = 50; median age, 56.5 years; 58% women).
• All participants were asked to complete self-reported questionnaires for assessment of IBS symptoms at weeks 2 and 4 and underwent a glucose hydrogen breath test to check for small intestinal bacterial overgrowth (SIBO) with a repeat test at 4 weeks for those who tested positive at baseline. Patients were assessed at week 4 for symptom severity, health-related quality of life, compliance with the medication or diet, and adverse events.
• The primary endpoint was alleviation of composite symptoms, including abdominal pain or discomfort and stool consistency or frequency, at week 4. Secondary outcomes included alleviation of individual symptoms, improvement in health-related quality of life, anxiety and depression scores, and eradication of SIBO.

TAKEAWAY:

• The difference in response rates on the composite symptom assessment was not statistically significant between the rifaximin and diet groups at week 4 (56% vs 48%, P = .423).
• At week 2, more patients in the rifaximin vs diet group had alleviation of global symptoms (90% vs 72%, P = .022), bloating (84% vs 58%, P = .004), abdominal pain (80% vs 58%, P = .017), and stool consistency (84% vs 66%, P = .038). However, individual symptoms continued to improve in the diet group, and both groups achieved similar efficacy rates at week 4 (P > .05 for all).
• The rifaximin group had higher adherence to treatment than the diet group (95.9% vs 77.8%; P = .008).
• Eradication of SIBO was observed in 63.6% of patients in the rifaximin group and 50% in the diet group, whereas health-related quality of life and anxiety and depression scores improved similarly in both groups.
• Both treatments showed similar safety profiles, with no serious adverse events and comparable rates of minor adverse events between groups.

IN PRACTICE:

“Given the practical challenges of implementing the LFD [low-FODMAP diet] in many parts of the world, rifaximin may serve as an alternative,” the authors wrote.

SOURCE:

This study, led by Kee Huat Chuah, Universiti Malaya, Kuala Lumpur, Malaysia, was published online in Alimentary Pharmacology & Therapeutics.

LIMITATIONS:

Researchers used the Rome III criteria for diagnosis of IBS, instead of the Rome IV criteria, and modified the FDA-recommended definition of composite symptom improvement to include both abdominal discomfort and pain. The follow-up duration was too short to assess the long-term efficacy of either treatment. The nature of the interventions prevented patient blinding, and the study was underpowered to evaluate the role of SIBO. Furthermore, the small number of participants in subgroups limited the ability to draw definitive conclusions.

DISCLOSURES:

This study was funded by the UMSC C.A.R.E research grant. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.