Simulation of vancomycin peak and trough concentrations using five dosing methods in 37 patients

Area of Science:

• Pharmacology
• Pharmacokinetics
• Clinical Pharmacy

Background:

• Vancomycin dosing requires precise pharmacokinetic parameter estimation for optimal therapeutic outcomes.
• Existing dosing nomograms and simulation methods vary in their ability to predict effective vancomycin serum concentrations.
• Accurate prediction of vancomycin peak and trough levels is crucial for efficacy and minimizing toxicity.

Purpose of the Study:

• To evaluate and compare the accuracy of five different vancomycin dosing methods (Matzke, Moellering, Nielsen, Lake-Peterson, and manufacturer's) in achieving target peak and trough serum concentrations.
• To assess the performance of these methods in predicting systemic drug clearance.
• To identify the most suitable initial dosing strategy for vancomycin therapy.

Main Methods:

• Simulation of five vancomycin dosing regimens in 37 patients.
• Collection of ten serum samples post-infusion for pharmacokinetic analysis.
• Nonlinear iterative least squares regression and a two-compartment, open-infusion model to estimate pharmacokinetic values.
• Simulation of steady-state peak and trough concentrations using patient-specific pharmacokinetic values and each dosing method.

Main Results:

• All simulated dosing methods underpredicted actual vancomycin systemic clearance.
• The Nielsen method exhibited the lowest prediction of drug clearance, while the Matzke method recommended the highest dosage.
• Only 3-16% of patients achieved the recommended vancomycin peak and trough concentrations across all simulated methods.
• No single method demonstrated satisfactory performance in attaining desired vancomycin therapeutic ranges.

Conclusions:

• Current vancomycin dosing methods demonstrate limitations in accurately predicting pharmacokinetic parameters and achieving target serum concentrations.
• The simulated methods, including the manufacturer's recommendations, were inadequate for ensuring therapeutic vancomycin levels.
• The Lake-Peterson method is suggested as a potential initial approach, but requires close patient monitoring and dosage adjustments.