How cyclosporine reduces mycophenolic acid exposure by 40% while other calcineurin inhibitors do not.

The most frequently used immunosuppressive treatment in kidney transplant recipients is the combination therapy of a calcineurin inhibitor (CNI) and mycophenolate mofetil, with or without corticosteroids. Cyclosporine and tacrolimus are the 2 CNIs registered for this indication. Also, in the treatment of glomerular diseases, CNIs and mycophenolate are being used on a worldwide scale, either alone or as combined treatment. In January 2021, the US Food and Drug Administration approved voclosporin, a novel CNI, for the treatment of adult patients with active lupus nephritis. There is a clinically relevant drug-drug interaction between cyclosporine and mycophenolate. As a result of cyclosporine-induced inhibition of the enterohepatic recirculation of mycophenolate, the mycophenolic acid area under the curve is significantly lower (40%) in case of cyclosporine coadministration compared with cotreatment with either tacrolimus or voclosporin (or no CNI cotreatment). The aim of this mini review is to summarize this potential drug-drug interaction and explain how cyclosporine affects the pharmacokinetics of mycophenolate. The optimal dose of mycophenolate mofetil is likely to depend on the CNI with which it is coadministered. Furthermore, clinical implications are discussed, including the potential emergence of mycophenolic acid-related adverse effects after discontinuation of cyclosporine cotreatment.