Which dose range supports early target vancomycin exposure in patients with obesity?

A loading dose (LD) around 20 mg/kg (ceiling 2 g) appears to result in early attainment of area under the concentration‒time curve (AUC)_0–24 target in patients with overweight or obesity receiving vancomycin, according to a study.

A total of 209 patients (aged ≥15 years, median BMI 27.2 kg/m²) who received vancomycin for ≥3 days and had ≥2 trough concentration measurements from four Japanese hospitals (2012‒2025) were included in the analysis.

The investigators estimated AUC_0–24 and steady-state AUC₂₄ (AUC_ss) using Bayesian software. They also conducted multivariate logistic regression analyses to identify factors associated with achieving target AUCs (AUC_0–24: 400–500 μg·h/mL; AUC_ss: 400–600 μg·h/mL).

LD showed an independent association with achieving target AUC_0–24 (odds ratio [OR], 1.08, 95 percent confidence interval [CI], 1.02‒1.15). LD approximately 20 mg/kg correlated with early target exposure.

For maintenance therapy, estimated glomerular filtration rate (eGFR; OR, 0.979, 95 percent CI, 0.964‒0.995; p=0.008) and maintenance dose (MD; OR, 1.050, 95 percent CI, 1.010‒1.090; p=0.018) showed independent associations with AUC_ss attainment.

Pragmatic interim MD ranges were about 9.2 mg/kg/day for patients with eGFR <30 mL/min/1.73 m², 16.2 mg/kg/day for participants with eGFR 30‒60 mL/min/1.73 m², and 26.3 mg/kg/day for those with eGFR >60 mL/min/1.73 m².

“MD and renal function were independent predictors of AUC_ss, informing interim renal-stratified MD ranges until therapeutic drug monitoring (TDM) results become available,” the investigators said. “Early TDM remains essential given significant inter-individual variability.”