I'm currently on Remicade, Lialda, Rowasa, Cortenema, VSL#3 and Lomotil. I've failed therapy and am awaiting surgery. Azathioprine was actually working for me when I developed pancreatitis and had to stop taking it.
There are several options starting out, it just takes awhile to find the one that is right for you.
Since you are having so much pain while already taking Percocet, you might call your primary physician and see if they will give you Flagyl or prednisone just until you can see your GI.