Conversion to tacrolimus for the treatment of cyclosporine-associated nephrotoxicity in heart transplant recipients.

Many heart transplant recipients experience nephrotoxicity caused by cyclosporine. Tacrolimus has been associated with similar efficacy and safety in heart transplant recipients compared with cyclosporine. It is unknown whether there is any benefit to switching calcineurin inhibition from cyclosporine to tacrolimus in heart transplant recipients with presumed cyclosporine nephrotoxicity. We report five such cases in which this approach was used successfully. In these cases, the heart transplant recipients had bland urine sediments, low urinary sodium concentrations, adequate cardiovascular and systemic hemodynamics, and cyclosporine levels within or below the therapeutic range as defined by heart transplant criteria. The mechanism of renal failure in these patients was believed to be consistent with renal hypoperfusion secondary to cyclosporine-induced renal vasoconstriction. Conversion to tacrolimus resulted in a prompt and significant improvement in serum creatinine concentrations in these patients (P = 0.002). This report shows that conversion to tacrolimus may represent a useful therapeutic strategy to reduce cyclosporine-associated renal failure in recipients of orthotopic heart transplants.