Azathioprine is an immunosuppressive medication. It is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, systemic lupus erythematosus and in kidney transplants to prevent rejection. 

Tacrolimus is an immunosuppressive drug. It is used after allogeneic organ transplant to lower the risk of organ rejection and also as a topical medication in the treatment of T-cell-mediated diseases such as eczema and psoriasis.