Conversion from tacrolimus to cyclosporine microemulsion therapy in liver transplant recipients

The calcineurin inhibitors cyclosporine and tacrolimus have distinct advantages and drawbacks. Therefore it is important to tailor their use to the patient's tolerance. In some patients, the need to ameliorate the adverse effects of tacrolimus may necessitate a switch to cyclosporine-based therapy. Rescue therapy with a cyclosporine microemulsion (Neoral)-based regimen for transplant patients intolerant of tacrolimus has been evaluated to assess the best method of switching and determine the initial and maintenance doses of Neoral in children and adults. Our aims were to evaluate not only these facets, but also the pharmacokinetics of Neoral in stable patients, including target 2-hour postdose blood concentrations (C2) of cyclosporine in liver transplant recipients. Eighteen liver transplant patients switched from tacrolimus to Neoral underwent a program of cyclosporine blood level monitoring. The conversions were conducted safely; the incidence of acute rejection episodes was low (11.1%). Statistical analysis showed that the C2 correlated with the area under the time-blood concentration curve of cyclosporine for 0 to 4 hours after dosing (R=0.970). We determined the maintenance doses of Neoral for pediatric and adult patients as well as the feasibility of C2 quantitated monitoring in liver transplantation.