Faktorer som lav hæmatokrit og lavt serumprotein, der giver en øget ubunden fraktion af tacrolimus, samt kortikoidinduceret øget metabolisme, betragtes som hovedårsagerne til den højere clearance, man finder hos transplanterede.
Factors such as low haematocrit and protein levels, which result in an increase in the unbound fraction of tacrolimus, or corticosteroid-induced increased metabolism are considered to be responsible for the higher clearance rates observed following transplantation.