Ramosetron May Effectively Treat IBS in Women

A study in Gastroenterology suggests that ramosetron reduces symptoms of irritable bowel syndrome (IBS) and increases stool consistency and quality of life (QoL) in women. The research is the latest to indicate that the medication, which is not available in the United States but is currently approved only for use in men in Japan and some other Southeastern countries, may also be effective in women.

Ramosetron is a 5-hydroxytryptamine (HT)3 receptor antagonist. It is not yet well-understood why ramosetron and other 5HT-3s, such as alosetron, seem to have gender-specific effects. (Alosetron is approved for use in men only, and with a box warning due to safety concerns.) Previous research has shown ramosetron to be more effective in men than in women, but findings presented earlier this year at Digestive Disease Week and the current study indicate that it can be effective in women.

Current treatments for IBS, including anti-inflammatory drugs and immune system suppressors, come with a host of potential side effects, ranging from the annoying (nausea) to the potentially life-threatening (pneumonia, increased chance of infection, and many others). Ramosetron in some studies has shown a very favorable safety profile.

The current study was a randomized, placebo-controlled, phase 3 study of 576 female outpatients with IBS-D (according to the Rome III criteria) at 70 academic gastroenterology departments in Japan. After a 1 week baseline period, subjects received either 2.5 μg of ramosetron (n = 292) or placebo (n = 284) once daily for 12 weeks. Primary endpoints were the monthly rates of response for relief from overall IBS symptoms and increased stool consistency at the last evaluation point.

A significantly higher proportion of patients given ramosetron reported global improvement (50.7%; 95% confidence interval [CI], 44.8—56.6) than patients given placebo (32.0%; 26.7–37.8)—a difference of 18.6% (95% CI, 10.7–26.5; P<.001). The relative risk was 1.58 (95% CI, 1.29—1.94) and number needed to treat was 6 (95% CI, 4–10).

A significantly higher proportion of patients in the ramosetron group reported increased stool consistency (40.8%; 95% CI, 35.1%—46.6%) than in the placebo group (24.3%; 95% CI, 19.4%–29.7%)—a difference of 16.5% (95% CI, 8.9%–24.0%; P<.001). Patients receiving ramosetron had significant reductions in abdominal pain and discomfort (P=.001) and greater improvement in QOL (P=.002) compared with placebo. Ramosetron induced constipation in 11.0% of patients.

Further research will be needed to confirm the findings.