Drug pharmacokinetics may be altered during liver transplantation. Cefotaxime (CTX), used as perioperative prophylaxis, demonstrates time-dependent killing and therefore continuous infusion might have pharmacodynamic advantages.Objectives
To determine the pharmacokinetics of CTX and desacetylcefotaxime (DCTX) in serum, bile and urine during continuous and intermittent infusion when performing liver transplantation.Methods
Fifteen patients undergoing liver transplantation were studied after continuous infusion (CI) (4000 mg iv per 24 h following a loading dose of 1000 mg) and intermittent bolus infusion (BI) (1000 mg iv four times daily). Samples were collected during the first 48 h after liver transplantation. Concentrations of CTX and DCTX were determined by HPLC.Results
During surgery, the mean concentration in serum after CI was 18 mg/L. The lowest serum concentration was 5 mg/L in the CI group and levels were undetectable in the BI group. Target serum concentrations of ≥4 mg/L were reached for 100% of the dosing interval during CI and ∼60% during BI. Post-operatively, the mean concentration in serum after CI was 26 mg/L. The lowest serum concentration was 8 mg/L in the CI group and levels were undetectable after BI. The peroperative pharmacokinetics of CTX in this patient group were deranged and variable, mainly caused by an increased volume of distribution and decreased hepatic clearance. Metabolism was hampered, but DCTX area under the curve (AUC)/CTX AUC ratios varying between 0.7–0.9 were reached peroperatively. Post-operatively, DCTX AUC/CTX AUC ratios were higher (1.1–1.4). Unchanged CTX in bile was ∼0.1% of the administered dose, leading to concentrations >4 mg/L throughout the dosing interval for both regimens.Conclusion
Although an intermittent bolus infusion of CTX 1000 mg produces t > target concentration for 60% of the dosing interval during liver transplantation, serum concentrations may be insufficient during the reperfusion phase. Continuous infusion overcomes this. Post-operatively, CTX clearance is impaired by decreased metabolic clearance and there is substantial accumulation of DCTX. In bile, sufficient concentrations of CTX and its active metabolite are reached with both regimens.