Rifaximin was found to improve abdominal pain symptoms in patients with irritable bowel syndrome with diarrhea (IBS-D), according to research presented at the American Association of Nurse Practitioners (AANP) Annual Meeting, held June 18 to 23, 2019 in Indianapolis, Indiana.

Researchers from the University of Texas McGovern School of Medicine in Houston conducted a phase 3 study in which they administered rifaximin 550 mg 3 times daily to patients with IBS-D as reflected by a meal daily abdominal pain score of ≥3. Abdominal pain was assessed daily and ranked on a scale of 0-10. Patients received rifaximin for 2 weeks and were evaluated during a 4-week period; patients who reported abdominal pain during an additional 18- to 22-week evaluation period received a second 2-week rifaximin course. Patient subgroups were defined by baseline abdominal pain scores of <5 (group A), ≥5 to <8 (group B), and ≥8 (group C).

A total of 2579 patients received the first rifaximin course (mean age, 46.4 years; 68.2% women). Mean baseline abdominal pain score was 5.5. Of the evaluable patients (n=2438), response to rifaximin was observed in 40.4%, 47.0%, and 43.1% of patients in groups A, B, and C, respectively. Response for the individual abdominal pain component was observed in 57.0%, 57.9%, and 49.5% of patients, respectively.

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A total of 328 patients experienced symptom recurrence and received repeat therapy with rifaximin; median baseline abdominal pain score at repeat treatment was 4.4. Response to repeat rifaximin treatment was reported in 38.6%, 34.8%, and 27.8% of patients in groups A, B, and C, respectively. Response for abdominal pain component was reported by 57.9%, 50.6%, and 50.0% of patients, respectively.

“In adults with IBS-D treated with rifaximin, a high percentage had clinically meaningful improvement in abdominal pain, irrespective of baseline abdominal pain severity category and treatment course (first vs repeat treatment),” the authors concluded.

Disclosure: Two of the study authors are employed by Salix Pharmaceuticals.

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Reference

Allen C, Lembo A, Heimanson Z, Cash BD. Characterization of abdominal pain response to rifaximin in patients with irritable bowel syndrome with diarrhea (IBS-D) by baseline pain severity. Presented at: The 2019 American Association of Nurse Practitioners (AANP) Annual Meeting; June 18-23, 2019; Indianapolis, IN. Poster 33.

This article originally appeared on Clinical Advisor