Rusty, the testing would surely have been done on people with unaltered GI tracts, but the colon doesn’t have much to do with it. Even if it did, loss of the colon would more likely reduce absorption than otherwise. In any case, budesonide goes to the liver first, via the portal circulation, and most of it is inactivated there. It nevertheless is a possible cause of your side effect, just not a very likely one.