All pharmacologic therapies for irritable bowel syndrome with diarrhea (IBS-D) or mixed stool (IBS-M) perform better than placebo, but alosetron and ramosetron appear to be most effective, according to a recent systematic review and network meta-analysis.
Researchers analyzed randomized controlled trials published through January 2019 that looked at the efficacy of alosetron, eluxadoline, ramosetron, and rifaximin in adult patients with IBS-D or IBS-M. Data were pooled using a random-effects model, and safety and efficacy of all therapies were reported. The results were published April 17 by Gut.
Eighteen trials that included 9,844 patients were eligible for the analysis. Of these, seven trials examined alosetron, five examined ramosetron, two examined rifaximin, and four examined eluxadoline. (Ramosetron is not currently available in the United States.) All four drugs were superior to placebo for both types of IBS at two weeks. Alosetron, 1 mg twice daily, was most effective as measured by improvement in abdominal pain and stool consistency, while ramosetron, 2.5 µg once daily, was most effective for abdominal pain. Adverse events were more common with these two drugs than with placebo. Rifaximin, 550 mg three times daily, had the best safety outcomes and was the only drug that was not associated with increased constipation.
The researchers noted that their data are based on indirect treatment comparisons and could be affected by confounding, among other limitations. However, they concluded that their results should help clinicians choose a second-line treatment for IBS-D and possibly IBS-M based on patients' most troublesome symptoms and on efficacy and safety.
“Alosetron and ramosetron remain unavailable in many countries,” the authors added. “Given the chronic and frequently debilitating nature of IBS, this lack of availability may need to be reconsidered, in order to widen access to potentially effective second-line treatments for those patients with IBS-D or IBS-M when conventional first-line therapies fail.”