When converting maintenance renal allograft recipients from Sandimmune (cyclosporin A [CsA]) to Neoral (CsA-microemulsion [CsA-ME]), a dose conversion ratio of 1:1 may not be optimal, in part because of the variability in absorption of the CsA formulation of cyclosporine. After conversion using a 1:1 dose ratio, an individualized approach to the management of dosing was applied. In this article, close monitoring, which began at the time of conversion, and rapid response to potentially meaningful changes in cyclosporine trough levels early in the postconversion course were used to maintain patients' cyclosporine troughs at preconversion levels. The results of cyclosporine dose changes after converting stable, maintenance renal transplant patients from CsA (once daily and twice daily) to CsA-ME (twice daily) during 52 wk of follow-up are reported. Most patients (87.2%) required CsA-ME dose reduction to maintain preconversion trough levels, and 64% of the patients attained their CsA-ME maintenance dose by study week 4. Logistic regression analysis identified one significant predictor concerning the week 52 CsA-ME dose: patients converted from CsA doses > or = 4.0 mg/kg per d were more likely to require dose reduction (P < 0.0001). Although firm guidelines for dose modification after conversion from CsA to CsA-ME cannot be provided because of the individual nature of cyclosporine absorption, an individualized approach to patient management is recommended. Patients with higher CsA doses before conversion are particularly likely to require dose reduction early in the postconversion course. With CsA-ME, good absorbers of cyclosporine remain good absorbers, or become better absorbers, whereas poor absorbers become good absorbers.
Relationship Between Genetic Polymorphism and Tacrolimus Concentration-Dose Ratio in Renal Transplant Patients
