# Low-Dose Alosetron Controls IBS Symptoms With Minimal Increases in Constipation



## Jeffrey Roberts (Apr 15, 1987)

*Low-Dose Alosetron Controls IBS Symptoms With Minimal Increases in Constipation*NEW YORK (Reuters Health) Aug 15 - An efficacy and safety study of three doses of alosetron (Lotronex) in women with severe diarrhea-predominant irritable bowel syndrome (d-IBS) showed that all three treatment regimens produced similar global improvement in symptoms, but the lowest dose was associated with the lowest rate of constipation.Susan H. Gordon of GlaxoSmithKline in Research Triangle Park, North Carolina, and associates conducted a randomized 12-week trial of three dosage regimens of alosetron -- 0.5 mg daily, 1 mg daily and 1 mg twice a day -- each compared with placebo, in 705 women with severe d-IBS.Disease severity was assessed on the seven-point Likert Global Improvement Scale at baseline and at 12 weeks. Secondary endpoints were relief of IBS pain and discomfort, and bowel symptom improvements."All of the doses were significantly better than placebo," Gordon told Reuters Health, noting that "the study wasn't powered to compare lower dose and higher dose."Specifically, response rates at 12 weeks were 50.8% in the 0.5 mg alosetron daily group, 48.0% in the 1.0 mg daily group, 42.9% among patients in the 1 mg twice daily group, and 30.7% in the placebo group, according to the team's report in the August issue of the American Journal of Gastroenterology.Bowel symptoms improved in all active treatment groups in a dose-related fashion. Constipation occurred in 9%, 16% and 19% of those on 0.5 mg, 1 mg daily and 1 mg twice daily, respectively.There was one episode of fecal impaction with the highest dose regimen. One episode of intestinal obstruction and one of ischemic colitis occurred in the 0.5 mg group. All of these events resolved on drug withdrawal."This study demonstrates that women with severe d-IBS benefit from once daily alosetron dosing with 0.5 mg and 1 mg as well as 1 mg twice daily," the investigators conclude.Gordon noted that the Lotronex prescribing information states: "To lower the risk of constipation, Lotronex should be started at a dosage of 0.5 mg twice a day. Patients well controlled on 0.5 mg twice a day may be maintained on this regimen. If, after 4 weeks, the 0.5 mg twice-daily dosage is well tolerated but does not adequately control IBS symptoms, then the dosage can be increased to up to 1 mg twice a day, the dose used in controlled clinical trials."She advised that "Lotronex should be discontinued in patients who have not had adequate control of IBS symptoms after 4 weeks of treatment with 1 mg twice a day."Am J Gastroenterol 2007;102:1709-1719.


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