Drug Interaction Study of Apixaban With Cyclosporine and Tacrolimus

Life- and graft-threatening complications in solid organ transplant patients have been greatly reduced due to the potent immunosuppressive agents like calcineurin inhibitors (CNI) that include cyclosporine and tacrolimus. Venous thromboembolism (clots in legs or lungs) in transplant recipients is often difficult to manage due to polypharmacy and potential for drug interactions. More than 90% of renal transplant (RT) recipients are maintained on a CNI-based immunosuppressive regimen. Cyclosporine is an inhibitor of many metabolic pathways including cytochrome P450 (CYP) 3A4, permeability glycoprotein (P-gp) and, breast cancer resistance protein (BCRP). Tacrolimus shares some of the distributive and metabolic pathways of cyclosporine. Apixaban is a combined substrate of CYP3A4, P-gp and, BCRP and thus has the potential for drug interactions with cyclosporine and tacrolimus. Apixaban levels that are too high or too low could be a problem for transplant patients. The purpose of this study is to determine what happens to apixaban blood levels when given in combination with cyclosporine or tacrolimus.