Trough Level and Tacrolimus Variability of Early Converted Once-Daily Tacrolimus: 1-Year Follow-up Study

Long-term transplant outcomes are considered a crucial point for kidney transplantation. Follow-up studies in patients receiving early conversion to once-daily tacrolimus (TAC-OD) are still limited. We aimed to investigate tacrolimus trough level (C_min), intrapatient variability of tacrolimus dose-normalized C_min (TAC-C_min/D), along with other outcomes between twice-daily tacrolimus (TAC-BID) and early converted TAC-OD.

This study was a single center, retrospective, cohort study. All new kidney transplant patients who received tacrolimus and presented an estimated glomerular filtration rate of more than 45 mL/min/1.73 m² on the day of hospital discharge were included. Studied patients were divided into the standard TAC-BID and patients who were converted from TAC-BID to TAC-OD on the day of hospital discharge. We followed patients for 1 year after transplantation.

At the first follow-up visit, C_min of TAC-OD was significantly lower than that of TAC-BID. However, C_min and estimated glomerular filtration rate were comparable between TAC-BID and TAC-OD throughout 1-year follow-up. TAC-OD also provided a lower intrapatient variability of TAC-C_min/D compared with TAC-BID when observed after 6 months post transplantation (17.40% and 23.27% for TAC-OD and TAC-BID, respectively; P = .13). The renal function, as well as other adverse outcomes, was similar between 2 formulations.

TAC-OD provided a similar C_min with comparable renal function compared with TAC-BID during 1-year follow-up. In addition, TAC-OD is likely to have a benefit of a lower intrapatient variability of tacrolimus.

Early conversion from TAC-BID to TAC-OD with 1:1 ratio can be used with close long-term monitoring.