Comparing Vancomycin Area Under the Curve With a Pharmacist Protocol that Incorporates Trough and Maximum Doses at a Children's Hospital.

OBJECTIVE

Updated vancomycin guidelines suggest dose adjustment based on area under the curve in a 24-hour period (AUC). This study aims to determine whether a pharmacist managed vancomycin protocol that incorporates maximum dosing paired with trough monitoring can achieve appropriate vancomycin AUC exposures.

METHODS

A retrospective review was performed evaluating vancomycin usage from October 2018 through September 2019 at a children's hospital. Patients with less than 4 doses or lack a trough concentration were excluded. Vancomycin AUC were estimated using 2 calculations: 1) the Le method, incorporating age and serum creatinine, and 2) the trapezoidal method based upon population data and patient-specific trough. Target AUC ranges were assessed. AUC goals were 400 to 600 mg·hr/L, but due to known variations between calculations, a variance of 20 mg·hr/L was allowed for each end of the goal. Secondary analyses included evaluations of efficacy and toxicity.

RESULTS

Two-hundred twenty-three patients were included. Initial doses were estimated to meet AUC goals in only 63%. After trough-based dose modification, 81% achieved a therapeutic AUC. Using the trapezoidal method, therapeutic concentrations were found in 51% of patients based on the initial dose and 77% after dose modification. Only 6.3% of patients had kidney injury with only 1 of those patients having any calculated AUC > 600 mg·hr/L and none above 620 mg·hr/L. No clinical failures were identified.

CONCLUSIONS

Increased initial dosing in infants and children is needed to result in AUC exposures recommended in the guidelines. Maximum dosing paired with trough monitoring may be an alternative to AUC monitoring in areas that are unable to perform AUC calculations. Prospective data are needed to validate these conclusions.