Evaluation of teicoplanin concentrations for loading-dose optimization across BMI categories.

OBJECTIVES: This study aimed to evaluate the relationship between teicoplanin trough concentrations and loading doses and to identify the appropriate body-weight descriptor for loading doses across BMI categories. PATIENTS AND METHODS: This retrospective study included adult patients whose teicoplanin trough concentrations had been measured. Cumulative loading doses and trough concentrations were compared among the underweight (BMI < 18.5 kg/m2), normal-weight (BMI 18.5-24.9 kg/m2) and overweight/obese (BMI ≥ 25.0 kg/m2) groups. Trough concentrations at the guideline-recommended loading dose scaled to different body-weight descriptors were simulated using individual pharmacokinetic parameters to evaluate the target attainment rate (TAR) within the target range 15-30 mg/L. RESULTS: In total, 206 patients were analysed, comprising 35 underweight, 131 normal-weight and 40 overweight/obese patients. The overweight/obese group received significantly lower loading doses than the other two groups. In contrast, Day 4 trough concentrations did not differ significantly between the underweight, normal-weight and overweight/obese groups, with median concentrations of 23.2, 23.7 and 24.1 mg/L, respectively. Simulation analysis showed that total body weight (TBW)-based dosing achieved a high TAR in the underweight and normal-weight groups (84% and 85%, respectively) and a lower TAR (71%) with a higher median of 27.2 mg/L in the overweight/obese group. The body-weight descriptor yielding a higher TAR than TBW-based dosing in the overweight/obese group varied by target range, with overlapping 95% CIs indicating no clear superiority. CONCLUSIONS: Simulation analysis suggests that TBW-based loading doses may lead to teicoplanin overexposure in overweight/obese patients. Further studies are warranted to identify the appropriate body-weight descriptor for loading doses in this population.