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Valacyclovir and acyclovir pharmacokinetics in immunocompromised children

Lisa Bomgaars1, Patrick Thompson, Stacey Berg

  • 1Texas Children's Cancer Center, Baylor College of Medicine, Houston, Texas, USA. lbomgaars@txccc.org

Pediatric Blood & Cancer
|June 19, 2008
PubMed

Insights

Oral valacyclovir demonstrates good bioavailability and tolerability in immunocompromised children, supporting its use for herpes zoster treatment. This study provides key pharmacokinetic data for pediatric patients.

Area of Science:

  • Pharmacology and Therapeutics
  • Pediatric Infectious Diseases

Background:

  • Valacyclovir, an oral prodrug of acyclovir, is used for herpes simplex and zoster infections.
  • Limited pharmacokinetic and safety data exist for valacyclovir in pediatric populations.
  • This study addresses the need for data on acyclovir pharmacokinetics after valacyclovir administration in immunocompromised children.

Purpose of the Study:

  • To describe acyclovir pharmacokinetics following oral valacyclovir in immunocompromised pediatric patients.
  • To compare pharmacokinetic parameters of oral valacyclovir versus intravenous acyclovir.
  • To assess the efficacy of valacyclovir in treating active herpes zoster infections in children.

Main Methods:

  • Thirty-seven immunocompromised children were enrolled in two studies.
  • Pharmacokinetic data were collected from 32 patients after receiving oral valacyclovir (15 mg/kg).
  • Eleven patients also underwent pharmacokinetic sampling after intravenous acyclovir administration; three received valacyclovir for herpes zoster.

Main Results:

  • Mean C(max) for acyclovir after oral valacyclovir was 18.8 +/- 7 microM, with a total exposure of 4,106 +/- 1,519 microM min.
  • Acyclovir bioavailability from valacyclovir was approximately 64%.
  • The only reported toxicity was Grade 1 nausea and emesis in five patients; two of three herpes zoster patients showed complete lesion scabbing by day 9.

Conclusions:

  • Oral valacyclovir (15 mg/kg) was well-tolerated and showed excellent bioavailability in pediatric patients.
  • The findings support considering oral valacyclovir for treating herpes zoster in clinically stable pediatric oncology patients.
  • Further research into valacyclovir's use in pediatric populations is warranted.
Abstract

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