“…When used as sole immunosuppressive agents in canine renal allograft recipients, most antimetabolites studied have elicited unacceptably high adverse reactions such as anorexia, weight loss, gastrointestinal ulceration, and anemia 11,17,22 . Thus, the combination of antimetabolites with calcineurin inhibitors such as CsA or tacrolimus has been used to reduce the necessary antimetabolite doses, leading to decreased toxicity and increased efficacy in preventing rejection 11–14,17,22,24,26 …”