Vancomycin Therapeutic Regime Adjustment in Newborns and Infants with Bacterial Infection: Case Series.

Background: Vancomycin is used mostly to overcome infections caused by methicillinresistant microorganisms. There are no well-established administration protocols for neonates and infants, so the leak of a specific administration regime in that population may lead to serum concentrations beyond the specified range.

Objective: This case series evaluated the pharmacokinetics adjustment from a vancomycin therapeutic regimen prescribed to neonates and infants with bacterial infection at a neonatal public hospital intensive- care-unit, with the primary purpose to verify cases of nephrotoxicity.

Methods: Three neonates and four infants taking vancomycin therapy, hospitalized in a public hospital from November 2014 to March 2015, were included in the study. Vancomycin serum concentrations were determined by particle-enhanced-turbidimetric inhibition-immunoassay. The vancomycin concentrations were used for dose adjustment by USC*Pack-PC-Collection®, a non-parametric maximization program. The trough serum concentration range of 10 to 20mg.L-1 was considered therapeutic.

Results: Three patients had serum concentration outside the reference-range, one with subtherapeutic, and two with supratherapeutic concentrations. All patients had concomitant use of drugs which interfered with vancomycin distribution and excretion pharmacokinetics parameters, including drugs that may enhance nephrotoxicity. One patient showed signs of acute renal damage, by low vancomycin and creatinine estimated clearances.

Conclusion: The pharmacokinetic adjustment has been proven to be a useful and necessary tool to increase therapeutic efficacy and treatment benefits. The standard dose of vancomycin can be used to initiate therapy in neonates and infants admitted to the ICU, but after reaching the drug steady state, the dosing regimen should be individualized and guided by pharmacokinetic parameters.