Standard-dose versus high-dose acyclovir in children treated empirically for encephalitis: a retrospective cohort study of its use and safety.

Background: Intravenous acyclovir is the treatment of choice for herpes simplex virus encephalitis. In 2006, the American Academy of Pediatrics updated its dosing recommendations for children aged 3 months to 12 years to receive high-dose acyclovir (60 mg/kg/day). The association between acyclovir dose and toxicity is unclear.

Objective: The purpose of our study was to review our institution's experience with standard- and high-dose acyclovir for the empiric treatment of encephalitis.

Study Design, Setting And Patients: This retrospective cohort study included patients aged 1 month to 18 years who received acyclovir as empiric treatment for encephalitis between 2005 and 2009 at a tertiary care children's hospital. We excluded patients with baseline renal impairment and those without serum creatinine measurements prior to and during treatment.

Main Outcome Measure: The main outcome measure of this study was to compare the occurrence of renal injury or failure between children who received the standard- versus high-dose regimen.

Results: Sixty-one patients were included (n = 32 standard-dose; n = 29 high-dose). There was no statistical difference in change in serum creatinine from baseline between children who received standard- versus high-dose acyclovir (0 vs. 5.1 %; p = 0.79). One child in the standard-dose group and three children in the high-dose group developed renal injury or failure during treatment (3.1 vs. 10.3 %; p = 0.34). Children with renal injury or failure were older, had a longer length of stay, and longer duration of therapy than children without.

Conclusions: The incidence of renal injury or failure was similar between children who received standard-dose and high-dose acyclovir.