Vancomycin area under the concentration - time curve (AUC) monitoring in young infants and children

The 2 main methods used to measure the area under the concentration–time curve over a 24-hour period (AUC₂₄) are manual AUC₂₄ calculations and model-informed precision dosing using Bayesian dosing software.

Manual AUC₂₄ calculations can be performed with a minimum of 2 measured vancomycin plasma concentrations after steady state has been reached. The first (peak) concentration is usually measured 30 minutes after the infusion has finished, and the second (trough) concentration is usually measured immediately before the next scheduled dose. For vancomycin continuous infusions, the AUC₂₄ is the random plasma concentration (mg/L) multiplied by 24 hours.

Model-informed precision dosing uses software to predict an individual’s drug exposure based on predetermined population pharmacokinetic models. It incorporates relevant patient characteristics (such as weight, height and serum creatinine) to determine the patient’s likely drug exposure. It is difficult to obtain multiple blood samples in young infants aged 0 to 90 days and children, so a pragmatic approach is to use a single vancomycin concentration taken any time after the first dose is administered. The Bayesian dosing software used for adults cannot be used in children unless a paediatric-specific pharmacokinetic model is available.

In children, the utility of vancomycin AUC₂₄ monitoring depends on the availability of a clinician with expertise in manual AUC₂₄ calculations, or Bayesian dosing software for AUC₂₄ monitoring.

In young infants aged 0 to 90 days without abnormal kidney function, the Vancomycin Area Under the Curve Calculator for Young Infants can be used¹. At the time of writing, there are no validated calculators that can calculate the AUC₂₄ for young infants with abnormal kidney function.