EFFICACY OF OPEN-LABEL BISMUTH SUBSALICYLATE FOR THE TREATMENT OF MICROSCOPIC COLITIS

Background & Aims: The pathogenesis of the microscopic colitis syndrom e is unknown but may involve bacteria, an intestinal luminal antigen, and/or autoimmunity, It was hypothesized that bismuth subsalicylate wo uld resolve both diarrhea and colonic inflammation in microscopic coli tis because it possesses antidiarrheal, antibacterial, and anti-inflam matory properties, Methods: Thirteen patients with microscopic colitis (7 with subepithelial collagen deposition and 6 without) were treated with eight chewable 262-mg bismuth subsalicylate tablets per day for 8 weeks, Patients recorded the frequency of bowel movements daily, For ty-eight-hour stool collections and flexible sigmoidoscopy with 24 bio psies were performed before and after treatment in each patient. Resul ts: Twelve patients completed the trial. Eleven patients had a resolut ion of diarrhea and a reduction in fecal weight. The average time to r espond was 2 weeks, In 9 patients, colitis resolved, When present befo re treatment, subepithelial collagen thickening disappeared. Those com pleting the trial experienced no side effects, Posttreatment follow-up for 7-28 months shows that 9 patients remain well having undergone no further treatment, 2 are well but required retreatment, and 1 has con tinued diarrhea, Conclusions: Bismuth subsalicylate treatment for 8 we eks is safe and well tolerated, This regimen appears to be efficacious for the treatment of microscopic colitis and is worthy of further stu dy in a controlled trial.