The consequences of tacrolimus blood concentrations during the four weeks following marrow transplantation from an unrelated donor: a single-center experience.

In our institute, tacrolimus was started at a dose of 0. 03 mg/kg/day and adjusted to maintain a blood concentration between 10 and 20 ng/mL combined with short term methotrexate after bone marrow transplantation from an unrelated donor. Dose adjustment was performed strictly, in order to prevent grade II-IV acute graft-versus-host disease (GVHD) while avoiding renal toxicity of tacrolimus. Then, in this study, we retrospectively evaluated the tacrolimus blood concentration during the first 4 weeks after transplantation. The mean tacrolimus concentration of the eligible 52 patients was 17.41+/-4.84 (range, 9.5-33.4) ng/mL in the 1st week after transplantation, but declined to 13.7+/-4. 0 (range, 8.1-25. 6) ng/mL in the 2nd week. The dose of tacrolimus was decreased as follows: 0. 022+/-0. 005 mg/ kg/day (range 0. 011-0. 039) in the 1st week, and 0. 018+/-0. 007 mg/kg/day (range 0. 004-0. 040) in the 2nd week. The incidence of grade II-IV GVHD was 63. 0% and grade III-IV was 13. 9%. The individual variations of tacrolimus blood concentration did not affect the incidence of grade II -IV acute GVHD, as far as the concentration being maintained in the range of 14. 82+/-4. 22 ng/mL during the first 4 weeks after transplantation. In addition, the variations of tacrolimus concentration didn't associate statistically with renal toxicity.