Summary

Introduction: A prospective study was conducted to verify if habitual vancomycin doses can determine adequate serum concentrations in 25 term newborn infants with sepsis and 38 to 44 weeks and 5 days of postconceptual age. Purpose: The therapeutic response of neonatal sepsis by Staphylococcus sp., treated with vancomycin, was evaluated through its serum concentration monitoring. Method: Vancomycin serum concentrations were determined by fluorescence polarization immunoassay technique (TDX/Abbott). Results: Thirteen newborn infants (59,1%) presented adequate peak vancomycin serum concentrations (20-40 mg/ml) and 1 presented peak concentration with potential ototoxicity risk (>40 µg/ml). Only 48% presented with adequate trough concentrations (5-10 mg/ml) and in 7 cases (28%) revealed a potential nefrotoxicity risk (>10 µg/ml). There was no significant agreement among the normality for peak and trough vancomycin in the method TDx/Abbott® (McNemar test: p=0,7905). Conclusions: Recommended vancomycin schedules for term newborn infants with neonatal sepsis should be based on the weight and postconceptual age only to start antimicrobial therapy, with no existence of an ideal pattern of vancomycin doses. Thus, vancomycin dose must be individualized, reducing the risk of toxicity or under therapeutic dose effects.