The Monitoring of Immunosuppressive Therapy with Tacrolimus in Patients with Kidney Transplant, Based on the Pharmacokinetic Criteria

Background: Therapeutic drug monitoring (TDM) in patients with Chronic Kidney Disease (CKD) with kidney transplant, represents a major post transplant concern due to the characteristics of this special category of patients, particularities which can generate changes of the pharmacokinetic profile of the administered medication.
Material and methods: The current study is a retrospective pharmacokinetic study, over a period of 50 months, including a group of 36 kidney transplanted patients with CKD. Tacrolimus blood concentration was determined by a validated high-performance liquid chromatography method (HPLC), at a 12 hour time interval from the last administration of the immunosuppressive medication and before the following dose (Residual concentration, Cmin(trough)).
Results: During the monitoring of therapy, based on the pharmacokinetic criteria, 252 measurements of blood concentration were determined, 58 of these being outside the therapeutic window.
Conclusions: The results obtained show that it is mandatory to continue to monitor closely medical therapy based on the pharmacokinetic criteria in view of improving drug administration. The other ways of monitoring therapy: the clinical and biochemical criteria should not be overlooked. In addition, the interindividual variability of patients should be considered, as well as drug interaction which can alter the pharmacokinetics of tacrolimus.