Introduction: Calcineurin-inhibitors (CNI) have a narrow therapeutic window and warrant close therapeutic dose monitoring (TDM). CNI metabolism and consequently its serum trough concentrations (C0) depend on multiple factors, one of which is ethnicity. This prompted us to study the Adoport® trough levels in our patients from different ethnic background using a standard dosing regimen of  0.05mg/kg twice a day.
Materials and Methods: Renal transplant recipients at the Leicester Renal Transplant Unit between 01 January 2016 and 31 December 2016 were retrospectively studied.All patients were given tacrolimus as Adaport according to same formula as described above. Data was collected from the hospital electronic database.This included ethinicity, adaport trough level and serum creatinine.A mean value for tacrolimus trough concentraton for first 6 weeks and 6 to 12 weeks post transplantation was recorded and compared with serum creatinine and ethinic backgrounds.
Results: There were 116 recipients, 71% (n=82) were White, 20% (n=23) were Asian, 6% (n=7) were Black. 3% (n=4) were of other ethnicities. In the first 6 weeks following transplantation,42.7% of White,  26.1% Asian and 28.6% Black patients achieved therapeutic levels of tacrolimus (8-10 ng/mL,) Majority of the Asian (60.9%) and Black (57.1%) patients had sub-therapeutic trough levels.

Between 6 to 12 weeks of transplantation,41.5% of Whites, 26.1% of Asian and 14.3% of Black patients achieved therapeutic levels of tacrolimus. Majority of the Asian (56.5%) and Black (71.4%) patients had sub-therapeutic Adoport® levels. None of the black patients achieved supra-therapeutic levels of Adoport®.

Most of the patients, regardless of their tacrolimus levels, had serum creatinine levels between 101 to 200 μmol/L and eGFR between 30 to 59 mL/min/1.73 m².
Conclusion: Majority of the patients of Asian and Black ethnicity achieved sub-therapeutic levels (below 8ng/dl) of Adoport® in the first 3 months of renal transplantation. Sub-therapeutic and supra-therapeutic levels had similar kidney function when compared to those with  therapeutic levels at 3 months post transplantation. Further studies are needed to assess validity of tacrolimus dosing and long term effect on serum creatinine in recipients from different ethnic backgrounds.