Pharmacokinetics of Sirolimus and Tacrolimus in Liver Transplant Recipients With Tacrolimus Toxicity

Pharmacokinetics of Sirolimus and Tacrolimus in Liver Transplant Recipients With Early Nephrotoxicity and/or Hypertension Due to Tacrolimus

Pharmacokinetics of Tacrolimus and Sirolimus alone and in combination in liver transplant recipients.

Liver transplant patients receiving tacrolimus, and who experience side effects such as hypertension and renal dysfunction, will be converted to sirolimus with low-dose tacrolimus, or Tacrolimus withdrawal. This study will evaluate allograft function by serial clinical lab testing, the pharmacokinetics of sirolimus and tacrolimus, the glomerular filtration rate (GFR) and the potential side effect of sirolimus, such as marrow suppression and hyperlipidemia. Two pharmacokinetic evaluations are planned: once around the third post-transplant month and another one at about 12 months. Expected outcomes are, a better understanding of sirolimus pharmacokinetic parameters over time in pediatric/adult liver recipients and early efficacy and safety data of the sirolimus as a non-nephrotoxic alternative to tacrolimus.

Inclusion Criteria:

• Recipients of primary liver (cadaver/liver, whole/segmental) transplants 5- 30 years old.
• Rejection-free post-transplant course for at least 3 months
• Renal dysfunction (15% decrease in age-adjusted calculated creatinine clearance)
• Hypertension requiring anti-hypertensive mediations.
• Informed consent.
• Weight ≥15 kg.

Exclusion Criteria:

• Rejection or infections within 3 months of enrollment.
• Intent to continue TAC
• Active participation in ongoing studies of immunosuppressive agents.
• Lack of informed consent.
• Pregnant or breast feeding
• HIV positive