Impact of therapeutic plasma exchange on cyclosporine kinetics during membrane-based lipid apheresis

Cyclosporine is used widely as an immunosuppressant in transplant recipients and for various autoimmune diseases. In some cases, these patients require therapeutic plasma exchange (TPE). Cyclosporine is known to be highly bound to lipoproteins, and their removal by TPE would be expected to have an impact on drug dosing. We studied cyclosporine kinetics in a 54-year-old woman who is status post-cardiac transplant and has been receiving weekly TPE for familial hypercholesterolemia. We obtained serial measurements of cyclosporine, low-density lipoproteins, and high-density lipoproteins at scheduled times related to the dosing of the medication on days that she received TPE versus a day she did not. We also measured cyclosporine, low-density lipoprotein, and high-density lipoprotein levels in the fixed volume (3.5 L) of the discarded plasma. Our results show a similar rate of decline of serum cyclosporine levels on TPE days as compared with a day without TPE. Net cyclosporine in the discarded plasma was found to be approximately 1 mg per treatment or less, a relatively insignificant amount when compared with the ingested daily dose of 150 to 250 mg twice a day. Despite substantial removal of lipoproteins, there is minimal impact of TPE on serum levels of cyclosporine, and dosage adjustment is not needed for patients undergoing this procedure.