Background Vancomycin dosing regimens and individual pharmacokinetics vary in newborns. A time lag in achieving therapeutic levels often occurs with delays in treating sepsis or toxicity.
Aims To investigate initial therapeutic trough levels (10–15 mg/l) achieved by a standard dose (15mg/kg/dose 12 hourly) for all newborns compared to new dosing accounting for birth gestation and postnatal age.1
Methods Admissions from March 2010- January 2012 were included. Data on gestation, age, initial therapeutic level (pre 4th dose) and creatinine were analysed.
Results 111 treatment courses in 83 infants were evaluated. The new dosing increased the proportion of therapeutic levels [18/68 (26%) vs.16/43 (37%), p=0.29], greatest in infants ≥ 29 weeks at birth, ≥ 10 days old (12% vs. 66%). Toxicity decreased [21/68 (31%) vs. 9/43 (21%), p=0.28]. Sub-therapeutic levels were unchanged (40% vs. 43%). Creatinine was higher with toxic levels compared to therapeutic/low levels (p<0.0001). No infants with creatinine < 100 umol/l had toxic levels. 18/27 (66%) with toxic levels had a creatinine of > 100 umol/l.
Conclusions Dosing accounting for birth gestation and age resulted in a greater proportion of therapeutic levels and less toxicity but sub-therapeutic levels remain frequent. We recommend large scale population studies to determine the optimal dosing strategy.
Wallis, Williamson. Arch Dis Child F&N 2011; 96.
< 29 weeks at birth: < 10 days: 20mg/kg 18 hourly; > 10 days: 15mg/kg 12 hourly.
≥ 29 weeks at birth: < 10 days: 15mg/kg 12 hourly; > 10 days: 15 mg/kg 8 hourly.