Valacyclovir HCl (Valtrex™): An Acyclovir Prodrug with Improved Pharmacokinetics and Better Efficacy for Treatment of Zoster

  • M. Lynn Smiley
  • Alison Murray
  • Paulo de Miranda
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 394)


Oral administration of acyclovir (9-[2-hydroxyethoxy)methyl]-9H-guanine, Zovirax®) is effective treatment for mucocutaneous infections caused by herpes simplex virus type I (HSV1) and herpes simplex virus type 2 (HSV-2). In zoster, a debilitating disease caused by reactivation of varicella zoster virus (VZV), acyclovir accelerates healing, and decreases the incidence, severity, and duration of pain.1,2,3,4,5,6,7,8,9,10 However, as the oral bioavailability of acyclovir is limited (15–21%), it is difficult to achieve the high plasma drug concentrations required to inhibit VZV, and herpes viruses which are relatively insusceptible to acyclovir in vitro, e.g. Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Hï-íV-6. This limited bioavailability of acyclovir necessitates frequent dosing (5 times daily) and may not provide maximum therapeutic benefit. Thus, for the treatment of zoster and the suppression of CMV infections, higher oral acyclovir doses than are effective for the treatment of herpes simplex viruses infections or, in some cases, intravenous acyclovir are necessary in order to demonstrate benefit.


Herpes Simplex Virus Type Herpes Zoster Genital Herpes Bone Marrow Transplant Recipient Oral Acyclovir 
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© Springer Science+Business Media New York 1996

Authors and Affiliations

  • M. Lynn Smiley
  • Alison Murray
  • Paulo de Miranda

There are no affiliations available

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