Drug-Drug Interaction in a Kidney Transplant Recipient Receiving HIV Salvage Therapy and Tacrolimus

Concomitant use of immunosuppressive agents and antiretroviral drugs may lead to complex drug-drug interactions. The calcineurin inhibitor tacrolimus is metabolized by cytochrome P-450 3A4 (encoded by the CYP3A4 gene) and is a substrate of P-glycoprotein (encoded by the ABCB1 gene). Both pathways can be inhibited by protease inhibitors (PIs). The reduction in first-pass and postabsorptive metabolism of tacrolimus by PIs can lead to extreme …