Determination of the Appropriate Dose of Vancomycin for Pediatric Patients with Cancer

Childhood cancers are associated with a high risk of infection due to the pathophysiology and adverse effects of anticancer drugs. Although vancomycin (VCM) is often used for treating cancer-associated infections, there are limited studies on VCM dosing in childhood cancers. Therefore, we retrospectively investigated VCM dosing administered to pediatric patients with cancer at Nagano Children’s Hospital. The trough values of the dose were compared with pharmacists’ therapeutic drug monitoring (TDM) intervention and the revised antimicrobial TDM guidelines. Between April 2011 and March 2017, pediatric patients with cancer aged 1-12 years who were administered VCM were enrolled in the study. The daily dose, number of doses, trough value of VCM, and serum creatinine level at the start and end of VCM administration were compared. The average daily doses significantly increased from 45.8 mg/kg/day at the beginning to 61.8 mg/kg/day at the end of therapy in 29 patients aged 1-6 years. The number of doses significantly increased from 3 to 4 times daily. The trough value of VCM significantly increased from 5.0 μg/mL to 10.0 μg/mL. The serum creatinine level remained unchanged from 0.21 mg/dL to 0.20 mg/dL. In nine patients aged 7-12 years, the daily dose increased from 46.1 mg/kg/day to 60.0 mg/kg/day. The number of doses remained unchanged 4 times a day. The trough value increased significantly from 6.5 μg/mL to 10.2 μg/mL. However, the serum creatinine level remained unchanged from 0.24 mg/dL to 0.25 mg/dL. In pediatric patients with cancer, VCM doses to reach the target value of a trough concentration of 10 μg/mL or more were started with an administration of 61.8 mg/kg/day (15.5 mg/kg, every 6 h) for children aged 1-6 years and 60.0 mg/kg/day (15.0 mg/kg, every 6 h) according to the revised guidelines for those aged 7-12 years. VCM might reach the target trough value by further TDM.