Therapeutic drug monitoring
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Although therapeutic drug monitoring (TDM) of immunosuppressive drugs has been an integral part of routine clinical practice in solid organ transplantation for many years, ongoing research in the field of immunosuppressive drug metabolism, pharmacokinetics, pharmacogenetics, pharmacodynamics, and clinical TDM keeps yielding new insights that might have future clinical implications. In this review, the authors will highlight some of these new insights for the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus and the antimetabolite mycophenolic acid (MPA) and will discuss the possible consequences. For CNIs, important relevant lessons for TDM can be learned from the results of 2 recently published large CNI minimization trials. ⋯ Therefore, alternative pharmacokinetic (ie, MPA free fraction and metabolites) and pharmacodynamic approaches to better predict drug efficacy and toxicity are being explored. Finally, for MPA and tacrolimus, novel formulations have become available. For MPA, the differences in pharmacokinetic behavior between the old and the novel formulation will have implications for TDM, whereas for tacrolimus, this probably will not to be the case.