
Methods: A retrospective cohort study of vancomycin courses was performed at a tertiary care children’s hospital between January 1, 2010 and December 31, 2010. Eligible subjects were hospitalized children ≤ 18 years old who received ≥1 intravenous vancomycin course. A vancomycin courses were defined as continuous administration for ≥ 72 hours. Initial daily dose was defined as mg/kg of vancomycin in the first 24 hours, and categorized as < 40, ≥ 40 and < 50, ≥ 50 and < 60, and ≥ 60 mg/kg/day. The primary outcome was time in hours between initial vancomycin dose and first attainment of trough level of 10 mg/L. Hazard ratios were calculated using Cox proportional hazards regression.
Results: Overall, 315 patients received 432 courses. The most common reasons for prescribing vancomycin were suspected sepsis or blood stream infection (n=138, 32.7%), isolated fever (n=100, 23.7%), and skin or soft tissue infection (n=51, 12.1%). Seventy-one courses (16.4%) were prescribed to neonates, and 114 courses (26.3%) were prescribed to infants 1-12 months in age. The median course duration was 145.8 hours (IQR: 100.3-228.1 hours), and the median time to trough attainment ≥10 mg/L was 58.6 hours (IQR: 31.5-91.0 hours). Approximately 83% of all courses attained a trough level of 10 mg/L. Initial dose was a significant predictor of timely trough attainment (p=0.0087).
Conclusion: While high initial dosing leads to modest increases in proportion of courses with eventual trough attainment of 10 mg/L, hazard ratios markedly increased. Higher initial dosing can potentially reduce antibiotic selective pressure associated with trough levels <10 mg/L.
Initial daily dose (mg/kg/day) |
Number of courses |
% with trough attainment >10 mg/L |
Hazard Ratio |
<40 |
193 |
80.8 |
Ref |
≥40 and <50 |
165 |
83.0 |
1.213 |
≥50 and <60 |
49 |
89.7 |
1.488 |
≥60 |
25 |
92.0 |
1.874 |

S. Akyar,
None
S. Patel, None