Efficacy and Safety of Oral Rifaximin in Patients With Active Microscopic Colitis

Inclusion Criteria4

• Collagenous colitis (CC) or lymphocytic colitis (LC) diagnosed on colon biopsies reviewed by 2 separate pathologists
• CC will be defined histologically to be the following: thickness of the collagenous subepithelial table >10 micrometer using an ocular micrometer, inflammation in the lamina propria consisting of mainly lymphocytes and plasma cells, lack of crypt architectural distortion, and regenerative-appearing changes in the surface and/or crypt epithelium
• LC will be defined histologically to be the following: intraepithelial lymphocytes >20 per 100 epithelial cells in the subjective area of highest lymphocyte density, inflammation in the lamina propria consisting of mainly lymphocytes and plasma cells, and regenerative-appearing changes in the surface and/or crypt epithelium
• Subjects in active flare, defined as >3 watery/loose stools per day on >4 / 7 days over >4 weeks in the past 3 months.