Evaluation for optimal dosing of vancomycin in patients with different physical types

The sufficient dose to obtain an optimal trough concentration of vancomycin (VCM) in patients with non-standard physical types remains controversial. In this study, we examined the relationship between the dose and physical type in patients in whom an optimal trough concentration was obtained among VCM-treated patients. We retrospectively investigated the dose of VCM and physical type in patients treated with VCM between January 2012 and January 2017 at two medical institutions (n = 272). The physical type was classified using the body mass index (BMI). Patients with a BMI of <18.5 kg/m² were assigned to the lean group, those with a BMI of 18.5-24.9 kg/m² were assigned to the standard group, and those with a BMI of ≥25 kg/m² were assigned to the obesity group. The mean doses of VCM per time (mg/kg) to achieve the target trough concentration of VCM, 15-20 μg/mL, were 19.8 ± 4.3, 16.5 ± 3.7, and 13.7 ± 2.7 mg/kg in the lean, standard, and obesity groups, respectively. The dose per time to achieve the target trough concentration decreased significantly in association with an increase of BMI. The upper limit of the recommended dose (15-20 mg/kg) or higher in lean patients, and the lower dose in obese patients than the recommended dose might be appropriate to achieve the target trough concentration when we calculated the dose per time based on actual body weight.