Check out section 2.8.4 Immunomodulatory Drugs in the MG Manual, page 19:

Myasthenia Gravis: A Manual for the Health Care Provider (PDF)

IF you search for "Imuran side effects" in the forum you will get many specific threads on the topic.

Here is the WebMD page for Imuran:

http://www.webmd.com/drugs/drug-13983-Imuran+Oral.aspx?drugid=13983&drugname=Imuran+Oral

Here is the WebMD page for Cellcept:

http://www.webmd.com/drugs/drug-13983-Imuran+Oral.aspx?drugid=13983&drugname=celcept+Ora l

I have only been on Preds for less than a month, so it will be awhile before I start with immunosuppresents. When the time comes, my neurologist prefers Cellcept.

-Mark-