If I were to guess, I'd say your uc has spread in extent which is actually quite common with this disease -- it spreads from the rectum up the large intestine. Canasa is a suppository and it effects only the rectum which must have been where your uc was initially limited to. Apriso is an oral medication that covers the entire large intestine.
Although, if your GI is giving you an oral medication for disease that is limited to jut the rectum then it is a waste, as the oral meds are not good at reaching the rectum (therefore there are suppositories and enemas which are best at reaching the rectum, and rectum and sigmoid colon respectfully).
I'd call and ask the extent of your disease. Mine started at 14cms and spread to 50+cms during the last flare I'm fighting off.
34; flaring since 1/1/2013 w/3-4 daily bms;
Rx: Daily 50mg 6MP, Lialda, Rowasa, tapering Prednisone now @ 15mg
Dx: 2-2012 ulcerative proctosigmoiditis
Diet: Diet mods and supplements haven't done anything for me.
"You, my friend, have never been in remission during the time I've known you; inflammation in every scope" -quote my GI
Post Edited (iPoop) : 3/27/2013 11:32:54 AM (GMT-6)