Imuran Dosing in Crohn's Disease Study

This multi-center, double blind (patients and doctors do not know treatment group assignment), randomized (patients are put in 1 of 2 groups) clinical trial which will compare two 52-week-long azathioprine(AZA) dosing methods. The patients enrolled will all be taking steroids (prednisone or budesonide)or have just been prescribed a steroid. The patients will be either in remission on steroids, but cannot taper off without a flare, patients who are on steroids and are still having Crohn's symptoms, or patients who need to start taking steroids. After a two week screening period, patients fitting enrollment criteria will be begin taking study drug. Patients will begin to taper steroids per a set schedule, and taper off steroids completely by week 13. Patients who need to go back on steroids because of returned symptoms are allowed to, per a set schedule in the protocol. Patients will have monthly visits that include physical exams, blood tests and a quality of life questionnaire. Patients will be required to keep a diary of abdominal pain, liquid or soft stools and general well being. After 6 months, only patients in remission (patients not on steroids, and not having active symptoms) will be allowed to continue for last 6 months of the study. Study visits during the last 6 months will be every 2 months, and include physical exams and blood tests, and a quality of life questionnaire. Patients in the study may receive dose changes, and this will require additional blood tests for safety.