Intrapatient variability in tacrolimus exposure - a useful tool for clinical practice?

The narrow therapeutic window for calcineurin inhibitors (CNI) remains a challenge in the management of transplant recipients, with under-exposure risking acute rejection and over-exposure resulting in acute and chronic impairment of graft function. Optimisation of CNI exposure by computerised dosing and different monitoring strategies have long been an area of interest in the transplant literature (1,2).