Initial vancomycin dosing in pediatric oncology and stem cell transplant patients

BACKGROUND: Gram-positive bacteremia is a common infection in pediatric oncology and stem cell transplant (SCT) patients requiring therapy with vancomycin. Optimal dosing of vancomycin in this patient population has not been well established. METHODS: All pediatric oncology and SCT patients receiving vancomycin between October 2006 and March 2007 were included in this study. Therapeutic levels were defined as levels between 10 and 15 mg/dL and low therapeutic levels were between 5 and 9 mg/dL. Information regarding any recent or concurrent nephrotoxic medications was collected. RESULTS: Fifty-six patients received 82 courses of vancomycin during the study period. More patients (53.7%) received vancomycin for empiric therapy and 78% had recent or concurrent use of nephrotoxic medications. Using standardized vancomycin dosing guided by a computerized provider order entry system, there were significantly more patients who were in the subtherapeutic range than the supratherapeutic range (P=0.0023). There were also significantly more patients in the low therapeutic than the therapeutic range (P<0.0001). A small number of courses (3.5%) were associated with supratherapeutic levels. There was no association between the concurrent or recent use of nephrotoxic medications and vancomycin levels. CONCLUSIONS: Pediatric oncology and SCT patients with normal renal function require higher daily vancomycin doses than other pediatric patients.