Vancomycin Area Under the Curve Simplified.

Area of Science:

• Pharmacokinetics and Pharmacodynamics
• Infectious Diseases
• Clinical Pharmacy

Background:

• Serum trough concentrations are insufficient for monitoring vancomycin safety and efficacy.
• The daily area under the curve (AUC24) to minimum inhibitory concentration (MIC) ratio > 400 mg*h/L is a more robust dosing target.
• A practical method to estimate AUC24 from trough concentrations is needed.

Purpose of the Study:

• To develop and validate a mathematical model for estimating vancomycin AUC24 from serum trough concentrations.
• To provide a practical tool for optimizing vancomycin dosing regimens.

Main Methods:

• A mathematical model was developed to compute median and range AUC24.
• The model utilizes vancomycin dose (mg/kg) and observed serum trough concentration.
• Volume of distribution (Vd) and elimination constant (Ke) are incorporated, with population Vd values provided.

Main Results:

• Doses of 15-20 mg/kg achieve AUC24 > 400 mg*h/L with troughs ≥ 11 mg/L, even with Vd = 1 L/kg.
• With median Vd, troughs as low as 9 mg/L with doses ≥ 15 mg/kg can achieve AUC24 > 400 mg*h/L.
• An AUC24:MIC goal of > 400 can be met with MIC 1.5 mg/L using doses ≥ 15 mg/kg and targeting troughs ≥ 16 mg/L for Vd ≤ 0.7 L/kg.

Conclusions:

• Higher vancomycin doses (mg/kg) targeting lower troughs optimize AUC24:MIC goals > 400.
• Troughs of 15-20 mg/L are seldom necessary for organisms with MIC ≤ 1 mg/L.
• The model provides a practical approach for vancomycin therapeutic drug monitoring.