Constant rate infusion of vancomycin in premature neonates: a new dosage schedule

Aims Since vancomycin's bactericidal action has been shown to be time-dependent, a constant rate infusion over 24 h might result in a better bactericidal efficacy. The purpose of this study was to define a new dosage schedule in prematures. Methods Two vancomycin 24 h constant rate infusion schedules were tested in two groups of neonates. Postconceptional age (PCA) was 27 to 41 weeks in group 1 (n=24) and 28 to 51.5 weeks in group 2 (n=29). Group 1 neonates received continuous infusion of 10 to 30 mg kg(-1) day(-1), adjusted for PCA and weight. Group 2 was designed to take into account the significant relationship observed in group 1 between vancomycin clearance standardized on weight and PCA and consisted of a constant loading dose of 7 mg kg(-1) followed by continuous infusion of 10 to 40 mg kg(-1) day(-1) adjusted for PCA and weight. Results Mean vancomycin serum concentration at steady state was 11+/-3.1 mg l(-1) in group 1 and 15.4+/-6.2. mg l(-1) in group 2. Fifty-six percent of group 1 values vs 88% of group 2 values were between 10 and 30 mg(-1) at steady state (P<0.01). Both regimens were well tolerated. Conclusion A loading dose of vancomycin followed by constant rate infusion of the appropriate dose adjusted for PCA and weight might improve vancomycin concentrations in neonates.