Advances in antiviral therapy: acyclovir.

Acyclovir [9-(2-hydroxyethoxymethyl)guanine] is a newly licensed acyclic nucleoside analog that is active in vitro and in vivo against herpes simplex virus (HSV) and varicella zoster virus (VZV). This agent is available in the United States in topical and intravenous forms, and the oral preparation is currently being evaluated in clinical trials. The precise therapeutic role for acyclovir in patients with herpesvirus infections is still evolving. This article reviews the current status of this exciting new antiviral agent.