Impact of Malignancy Category on Vancomycin Dosage Requirements inPediatric Oncology Patients

Abstract

Objectives: To determine the dosage of vancomycin in milligrams/kilogram/day (mg/kg/day) required to achieve a trough value of 10 to 20 micrograms/milliliter (mcg/mL) in pediatric patients with differing types of malignancies. Methods: Retrospective review of pediatric patients with hematologic malignancy, solid tumor, or status post autologous or allogeneic hematopoietic stem cell transplantation (HSCT) receiving at least two doses of intravenous vancomycin with at least one evaluable trough concentration. Primary outcome was the dosage of vancomycin required to achieve first therapeutic trough value. Secondary endpoints included dosage requirement by age, proportion of patients achieving goal, incidence of supratherapeutic trough values and nephrotoxicity. Results: Mean dosage requirements were 72.5 [± 2.3] mg/kg/day among patients with hematologic malignancies, 66.5 [± 3.3] mg/kg/day in patients with solid tumors, and 77.3 [± 4.1] mg/kg/day in HSCT patients (p=0.12). Younger patients required significantly increased daily dosages in order to meet their trough goals in the hematologic malignancy and solid tumor groups (p<0.05). The proportion of patients achieving trough goals was also similar between groups (p=0.5). Supratherapeutic trough values were more common in the solid tumor groups (p<0.05). Nephrotoxicity occurred more frequently in the HSCT group (p<0.05). Conclusion: Vancomycin dosage requirements are similar between pediatric patients with differing categories of malignancies. Patients with solid tumors and HSCT appear to be at higher risk for supratherapeutic trough values, and HSCT patients appear to be at an increased risk for nephrotoxicity.