I have had experience with the steroid sparing effects of 6MP, a close cousin of azathioprine, and it worked for my Crohn's disease for about a year and a half before I had to stop due to a low WBC. That doesn't mean it will happen to you, but these drugs all have potential significant side effects. Like Prednisone, it will generally suppress your immune response, you may need periodic blood tests for blood or liver toxicity, and it can take a while for it to come on in effectiveness, but I surely hope it works for you! Some people with Crohn's have been on it for a long time with no problems like mine.