A retrospective review of vancomycin dosing in paediatric patients

Background: Vancomycin has antimicrobial activity against most Gram-positive pathogens. Reduced susceptibility of vancomycin to many microbes has necessitated higher target vancomycin trough levels (VTL) of 10-20mg/L. Paediatric dosing algorithms have remained unchanged despite higher VTL targets; increased doses are required. The study outcomes were to assess the impact of new dosing guidelines on VTL, time to target VTL and vancomycin-associated acute kidney injury (vAKI).

Methods: A single-centre review assessed 63 vancomycin treatment episodes between Apr-2016 and Feb-2019. Demographic data, treatment duration, daily vancomycin dosing and VTL were collected. Episodes were grouped as high-dose vancomycin (HDV) (≥60mg/kg/day) and low-dose vancomycin (LDV) (<60mg/kg/day). Target VTL was 10-20mg/L. AKI was defined by modified pRIFLE criteria as ≥50% increase in baseline creatinine within 7 days of treatment commencement. The project was registered with the local audit team.

Results: Initial VTL were significantly higher in the HDV group (mean 10.4, SD±4.7mg/L; n=20) than LDV (mean 7.9,SD±4.0mg/L;n=43), p=0.0397. Whilst time-taken to reach target VTL was improved in the HDV group (53.5±22.3 hours vs 66.1±37.1hours), this was statistically insignificant (p=0.2675). Paired t-tests revealed no significant changes to baseline creatinine in HDV (p=0.1267) and LDV (p=0.2006). No differences in vAKI incidence between the two groups were noted (p>0.05).

Conclusion: Increasing vancomycin dosages improved initial VTL but was insufficient to improve the length of time to reach target VTL. Reassuringly, there was no increase in vAKI incidence with HDV. The study suggests loading doses in paediatrics may be needed to improve time to target VTL.