Korean J Transplant.  2023 Nov;37(Suppl 1):S187. 10.4285/ATW2023.F-7737.

Usefulness of therapeutic drug monitoring with tacrolimus and mycophenolate in kidney transplantation

• Park DJ
• Park M
• Lim J
• Kim MH
• Hwang JK
• Kim HD
• Ban TH
• Choi BS
• Lee J

• KMID: 2551807
• DOI: http://doi.org/10.4285/ATW2023.F-7737

Abstract

Background
Tacrolimus and mycophenolate (MPA) are main maintenance immunosuppressive agents in kidney transplantation (KT). Therapeutic drug monitoring (TDM) of tacrolimus is useful to obtain a balance between allograft function and complications after KT. MPA levels also correlate closely with patient clinical outcomes, and it is a candidate for TDM analysis due to the high interindividual pharmacokinetic variability. MPA TDM is rarely assessed in Korea, therefore, we set up MPA TDM in our hospital for KT recipients and share our TDM experience of MPA along with TDM of tacrolimus.
Methods
TDM concentrations of tacrolimus and MPA were evaluated in KT recipients from April 2023 to July 2023. The performance of the TDM program was evaluated by comparing predicted trough concentrations based on patient dosing with actual measured blood trough levels at the outpatient’s next visit. Tacrolimus TDM was performed on a total of six outpatients, and MPA TDM was performed on three out of six patients.
Results
For tacrolimus, TDM predicted mean level was 6.69±1.49 ng/mL and the mean measured drug concentration was 6.37±1.52 ng/mL. For MPA, TDM predicted average was 4.66±2.42 mg/L and the mean measured level was 3.79±1.70 mg/L. For tacrolimus, the correlation was r=0.9389 and the mean difference between TDM predicted level and the measured level was 5.69%. For MPA, the correlation was r=0.9999, and the mean difference between TDM predicted level and the measured level was 3.66%.
Conclusions
Both tacrolimus and MPA showed a high correlation between predictive levels and trough level. Adjustment of the drug dose is necessary when the KT recipients blood drug concentration is subtherapeutic or toxic range. We believe that an individual patient-optimized MPA TDM assay can help maintain MPA therapeutic concentrations in KT recipients.