An AUC Target Simulation for Vancomycin in Patients With Class III Obesity

The objective of this simulation is to compare 24-hour vancomycin (Vanc₂₄) dosage requirements between a target area under the curve (AUC) versus a target trough approach in patients with class III obesity.

Adult patients were included if they received vancomycin in accordance with the University of Vermont Medical Center's class III obesity dosage protocol from June 2016 through December 2018. Patient-specific pharmacokinetic parameters were calculated for each patient using the Sawchuck-Zaske method. For this simulation, Vanc₂₄ dosages were calculated to achieve an AUC of 400 mg/L h and a trough concentration of 15 mg/L.

Sixty-three patients had Vanc₂₄ dosage requirements calculated. The median age was 59 years (interquartile range [IQR]: 51.5-68), body mass index (BMI): 45.7 kg/m² (IQR: 42.4-51.5), and 50.7% were male. The mean Vanc₂₄ dosage requirements were 3995 mg (standard deviation [SD] ±1673) in the target trough approach versus 2783 mg (SD ±1149) in the target AUC approach (P < .0001).

A target AUC approach required less vancomycin over a 24-hour time period relative to a target trough approach. Vancomycin therapeutic drug monitoring that explicitly targets AUC may reduce vancomycin exposure and potentially decrease the risk of nephrotoxicity in patients with class III obesity.