I participated in a study by GSK that started last August(2003). I also had to have a colonoscopey, bloodwork, etc. before I started. I was told there would be a 50/50 chance I would be taking a placebo. I did all the daily phone calls to GSK, etc. I had to have bloodwork every few weeks. I knew within days I did not have the placebo. In retrospect, not sure exactly what they were looking for as they started me on 2mg/day (1am and 1pm). Anyway, I am still on lotronex and it has certainly helped my situation... Possibly the studies now are looking closer at IC. It would probably be marketed more widely if they can prove it does not cause IC. I think too many doctors prescribed it for people with complaints of episodes of diarrhea, not IBS. I'm sure this could have caused some problems. Educating the physicians is not an easy task.... Good luck with the study!