The effect of H1 receptor antagonist on rectal sensitivity

Irritable Bowel disease is a functional bowel disorder with a high prevalence, caracterized by low respons on regular therapy and most of the time a poor quality of life. Previeus studies have shown that hypersensitivity of the rectum, measured by barostat, is one explanation of developping abdominal symptoms. This hypersensitivity is probably caused by the mastcell. A study with a mastcell stabilizator ketotifen reduced the rectal hypersensitivity and symptomsscore. However there was no change in mastcell activity seen, suggesting that the effect of ketotifen is due to H1 receptor antagonism. The aim of this study is to investigated if fexofenadine, a specific H1 receptor antagonist, will reduced rectal sensitivity and secondairy will lead to improvement of symptoms and quality of life.

IBS patients who will meet the Rome III Criteria will be randomized in a double blind placebo controlled trial with 8 weeks of treatment with 180-360 mg fexofenadine a day. Before and at the end of the treatment a barostat investigation will be performed for measuring the rectal sensititivity.

Inhibition of the H1 receptor will lead to an improvement of rectal sensitivity, followed by less abdominal symptoms in patients with irritable bowel syndrome.

12 weeks trial. 2 weeks screening, 8 weeks of treatment and 2 weeks foolow up.

During 8 weeks patients with IBS will recieved a treatment with Fexofenadine, an H1 receptor antagonist, or placebo.

The first 2 weeks 180 mg/day, then 6 weeks 360 mg/day. Before start and end of the study a barostat investigation will be performed for measuring the rectal sensitivity.