6MP and Imuran are very similar. I can't remember which, but one metabolizes into the other.
I do know there are some people on the forum who have switched from one to the other for various reasons - hopefully one of them will respond with more info :)
Pan-colitis and GERD diagnosed May 2003
Asacol 12 per day, Azathioprine 75mg, Rowasa and Canasa as needed
Aciphex, Effexor XR, BCP, Rhinocort nasal spray
Culturelle, Biotin, Folic Acid, Forvia, Calcium, and B12
Osteopenia (hip and spine) from prednisone use. Started Azathioprine because I was steroid dependent.
Co-Mod for the UC forum