Cefepime Pharmacokinetics in Liver Transplant Recipients in an Intensive Care Unit

The purposes of this study are to:

I. Characterize the plasma concentration-time profile of cefepime in liver transplant patients to determine the pharmacokinetic parameters in this patient population.

II. Perform stochastic modeling using the population pharmacokinetic parameters obtained in Specific Aim I to determine the ideal dose and dosing regimen of cefepime required to attain predetermined therapeutic targets in liver transplant patients.

The use of cefepime in liver transplant patients at conventional doses used for other patient populations leads to non-optimal drug exposure among liver transplant patients. Furthermore, using serum creatinine as a method of estimating creatinine clearance is not the optimal way to determine the best cefepime dose. The consequence of this non-optimal exposure is the unattainability of therapeutic targets. These therapeutic targets are correlated with positive microbiologic outcome and clinical cure.

Liver transplant patients in the ICU

Inclusion Criteria:

• Women and members of minority groups will be included in this study. However, as this study seeks to generate pilot data, there will be no specific statistical analysis comparing differences based on gender or race.
• Subjects receiving drugs known to induce or inhibit hepatic enzymes are not excluded from this study as cefepime is renally eliminated and not significantly metabolized by the liver.
• All liver transplant subjects are eligible for enrollment in this study, including subjects who have undergone a living related liver transplant.
• The pharmacokinetics of cefepime in children are significantly different from those of adults. For the purposes of this study only adults (aged > 18 years old) will be able to participate.

Exclusion Criteria:

• Subjects will be excluded if they are anemic (hemoglobin < 7 mg/dl), or are patients with severe gastrointestinal bleeding who are receiving packed red blood cells.
• Subjects who are receiving hemodialysis or other forms of renal replacement therapy (such as continuous veno-venous hemofiltration), or patients with a calculated creatinine clearance of < 10 ml/min will be excluded from the study.