One of the immunosuppressant medications given after a transplant to prevent rejection. The other name for it is azathioprine. It is taken by mouth as a pill.

an immunosuppressive drug (trade name Imuran) used to prevent rejection of a transplanted organ

An immunosuppressive drug originally used to prevent graft rejection in patients receiving kidney transplants. Imuran also is used to suppress the abnormal immune response in some patients with vasculitis, systemic lupus erythematosus, and rheumatoid arthritis.