Calcineurin inhibitors play the key role in current immunosuppressive therapy in transplantation medicine. We present our experience with tacrolimus as immunosuppressive therapy and the reasons for replacing tacrolimus with cyclosporine in some patients. We monitored graft function, serum lipid levels, and blood glucose concentration before and after immunosuppressant switch. The most common reason for change of immunosuppressive therapy was insulin dependent hyperglycemia; calcineurin inhibitor nephrotoxicity was the reason for switching immunosuppressive therapy in a small number of patients; and in one patient, the reason for immunosuppressive therapy switching was BK virus infection. Blood glucose normalized soon after the introduction of cyclosporine in the treatment. Monitoring of laboratory tests before and after immunosuppressive therapy switching showed the graft function to have remained unchanged.