Tacrolimus therapeutic drug monitoring in Tunisian renal transplant recipients: Effect of post-transplantation period

Background: Most previous studies having focused on therapeutic drug monitoring of tacrolimus in renal transplant recipients have assessed the clinical response of patients. The aim of this study is to investigate the influence of post-transplant delay on tacrolimus dose, trough levels (CO) and dose/CO ratio in a Tunisian renal transplant population. Patients and methods: A retrospective study including 110 renal transplant patients has been performed. Tacrolimus trough concentrations were adjusted according to the target range proposed by the European consensus conference on tacrolimus optimization. Samples for determination of tacrolimus blood level were subdivided according to the post-transplantation period into three groups. Results: The initial dose required was 0.17 +/- 0.05 mg/kg/day during the first 3 months after transplantation. A reduction of 36 and 65% of tacrolimus initial dose during the second (3-12 months) and third period after transplantation (>12 months), respectively, was required to maintain the concentration level within therapeutic range. These results were different from those found in other studies performed in different populations. We hypothesize that these differences in dosing requirement may be due to an interethnic polymorphism in the expression of enzymes involved in tacrolimus metabolism. Conclusion: These results could provide a simple therapeutic strategy to optimize tacrolimus prescription after renal transplantation in Tunisian,population. (C) 2013 Elsevier B.V. All rights reserved.