Hi Trace,
Azathioprine is the generic name (therefore the cheaper brand) of Imuran, which is an immune system suppressor used for lupus and RA. It's meant to ease our symptoms. Here's a link to follow http://www.medicinenet.com/azathioprine/article.htm for more info.
It can be tough but I hope you'll feel better. Please be sure to tell your doctor about any supplements or over the counter meds you might be taking because all these things can affect each other and us. Also, check the link for any possible food interactions, OK?
Wishing you Well,
Shar