hi there,
i have UC (diagnosed in 2001) and have been on asacol most of the time. however, i had about a year of experience with pentasa... the doctor at the time told me that it was the same thing as asacol, however, i found it to be less effective. another doctor later told me that they have the same active ingredient mesalamine, but pentasa reaches a different part of your track... i think asacol stays intact longer, so it gets released lower down in your system.