[摘要]：Backgrounds. Variability of blood trough concentration (C(o)) in immunosuppressant leads to rejection and graft loss after kidney transplantation. Methods. The aim of this study is to prospectively investigate the change of within-patient variability among stable kidney transplant recipients with conversion from twice-daily Prograf to the same milligram-for-milligram daily dose of once-daily Advagraf. Results. The mean age of 129 patients was 51.3 +/- 12.1 years. The conversion to Advagraf was administrated at 6.3 +/- 4.8 years after transplantation. The daily dose was changed from 4.7 +/- 2.0 mg to 4.9 +/- 2.1 mg after conversion. Only six patients increased daily dose by 16.7% to 25% to maintain target levels. The whole blood C(o) of tacrolimus before conversion was 5.9 +/- 1.7 ng/mL. The mean C(o) was significantly reduced after conversion to Advagraf; it was 4.9 +/- 1.5 ng/mL on the seventh day (P<0.001) and 5.4 to 5.5 ng/mL at 1 to 6 months (P<0.05). Forty-one (31.8%) patients have reduced C(o) of more than 25% on the seventh day. The percent coefficient of variation of tacrolimus C(o) more than 22.5% before conversion is associated with higher risk of reduced C(o) after conversion (P<0.05). Compared with before conversion, less kidney transplant recipients have percent coefficient of variation more than 22.5% after conversion (3.1% vs. 17.4% with P<0.01). Conclusions. The results support that conversion from Prograf to Advagraf among kidney transplant recipient leads to a significantly lower C(o) and within-patient variability of tacrolimus C(o). The within-patient variability of C(o) before conversion influences C(o) on the sevent day after conversion to Advagraf.
