Individualized vancomycin dosing in infants: prospective evaluation of an online dose calculator

Background: Empiric vancomycin dosing regimens fail to achieve recommended target trough concentra-tions of 10-20 mg/L in the majority of infants. This study assessed the performance of a model-based dosing calculator (Vanc App) in achieving target vancomycin concentrations at first steady-state level.Methods: This was a multicenter prospective study in four tertiary pediatric hospitals over an 18-month period. Infants aged 0-90 days with suspected Gram-positive sepsis requiring empiric vancomycin treat-ment were included if they did not meet any of the exclusion criteria: post-menstrual age (PMA) < 25 weeks, weight < 500 g, glycopeptide allergy, receiving extracorporeal membrane oxygenation, vancomycin use within the previous 72 h, and renal impairment. The Vanc App used a published population pharma-cokinetic model to generate a dose based on the infant's PMA, weight, creatinine, and target vancomycin concentration.Results: A total of 40 infants were included; 40% were female, median (range) weight was 2505 (700-4460) g and median (range) PMA was 37.4 (25.7-49.0) weeks. The median (range) vancomycin dose was 45 (24-79) mg/kg/day. All infants had trough vancomycin concentrations measured at steady-state (24-< 48 hours) and 30 (75%) infants achieved target concentrations. Five infants had supratherapeutic (me-dian 25, range 21-38 mg/L) and five had subtherapeutic (median 6, range < 5-9 mg/L) concentrations. An area under the concentration-time curve (AUC0-24) of 400-650 mg/L.h was achieved in 33 (83%) infants. There were no infusion-related reactions or nephrotoxicity.Conclusion: Individualized intermittent vancomycin dosing using a model-based online calculator resulted in 75% and 83% of infants achieving target trough and AUC0-24, respectively, at first steady-state level.There were no vancomycin-related nephrotoxicity or infusion-related reactions.(c) 2023 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.