I dug this up, interesting read. I was surprised at how few patients they tested some these drugs on or maybe that is the only trials they found to use. I am on Pentasa, according to the study it is a waste of money. I do notice a difference if I miss a dose. Maybe it is all in my mind?
http://www.acg.gi.org/media/releases/ajg201158a.pdf
http://www.acg.gi.org/media/releases/ajg201158a.pdf