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

Objective: 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. Methods: 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. Results: 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). Conclusion: 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.