Mesalazine with or without cholestyramine in the treatment of microscopic colitis: randomized controlled trial.
Collagenous colitis (CC) and lymphocytic colitis (LC) are chronic inflammatory diseases of the colon with a benign and sometimes relapsing course. Frequency among patients with chronic diarrhea and normal looking colonoscopy is around 10-15%. To date, treatment of CC and LC is not well defined. Data about these conditions are mostly derived from retrospective studies. The aim of the present study was to evaluate the response to treatment and the clinical course of CC and LC in a large group of patients prospectively diagnosed.
                A total of 819 patients underwent a colonoscopy because of chronic watery diarrhea and among them we found 41 patients with LC and 23 with CC. These patients were later randomized and assigned to treatment with mesalazine or mesalazine + cholestyramine for 6 months. Fifty-four patients (84.37%) had resolved diarrhea in less than 2 weeks. After 6 months a colonoscopy with biopsies was repeated. Clinical and histological remission was achieved in 85.36% of patients with LC and in 91.3% with CC, with a better result in patients with CC treated with mesalazine + cholestyramine. During a mean period of 44.9 months, 13% of patients relapsed; four with LC and three with CC. They were retreated for another 6 months. At the end of this period one patient with CC was still symptomatic and persistence of CC was confirmed at histology.
                Treatment with mesalazine seems to be an effective therapeutic option for LC to date, while mesalazine + cholestyramine seems to be more useful in the treatment of CC.
A single trial studying budesonide suggests that it may be effective for the treatment of active lymphocytic colitis. An ongoing placebo-controlled trial may confirm the benefit of budesonide. There is weaker evidence that mesalazine with or without cholestyramine may be effective for the treatment of lymphocytic colitis, but this benefit needs to be confirmed in a placebo-controlled study. No conclusions can be made regarding bismuth subsalicylate. These agents require further study before they can be recommended as treatment options for lymphocytic colitis. Further trials studying interventions for lymphocytic colitis are warranted.