Monitoring of tacrolimus as rescue therapy in pediatric liver transplantation.

The introduction of tacrolimus as rescue therapy represents a significant advance in the prevention of late graft failure and second liver transplantation. The authors report the blood level monitoring of tacrolimus as a rescue therapy in 21 children who underwent liver transplantation, and they report the dose-concentration relationship in the presence or absence of hepatitis C virus (HCV) in these patients. This was a retrospective study conducted from May 1993 to January 1997. Indication for the conversion from cyclosporine (CsA) to tacrolimus were acute rejection (62%), chronic rejection (33%), and CsA toxicity (5%). Mean daily dose in the first month was 0.32 mg/kg, whereas at the end of the follow-up period it was 0.14 mg/kg. Tacrolimus mean whole blood concentration levels were between 7.1 ng/ml and 9.4 ng/ml, without significant differences over time. Mean daily doses in HCV+ and HCV- patients were 0.08 and 0.24 mg/kg, respectively (p < 0.01), and mean concentrations were 8.3 and 8.4 ng/ml (NS). HCV+ children required a mean dose three times lower than the dose used in HCV- children to obtain the same tacrolimus trough blood level. Therefore, doses in HCV+ children must be decreased to achieve levels within the therapeutic range.