Valacyclovir in the treatment of genital herpes and herpes zoster

Genital herpes is prevalent and sometimes debilitating. Likewise, herpes zoster ('shingles') can be painful and often disabling. The treatment of these conditions has been advanced over the past two decades by the introduction of guanosine nucleoside antivirals such as valacyclovir (Valtrex), Glaxo Wellcome), the highly bioavailable prodrug of acyclovir (Zovirax), Glaxo Wellcome). This review describes the pharmacology, pharmacokinetics, clinical efficacy and tolerability of valacyclovir and considers its clinical attributes in the context of those of the antivirals, acyclovir and famciclovir (Famvir), SmithKline Beecham). The data demonstrate that valacyclovir is more effective than placebo and as effective as other antivirals in the episodic and suppressive treatment of recurrent genital herpes. Valacyclovir is the only antiviral shown to be effective with a short (3-day) course in the episodic treatment of recurrent genital herpes, as well as with once-daily dosing for daily suppressive therapy. In herpes zoster, valacyclovir is as effective as famciclovir and more effective than either placebo or acyclovir at facilitating cutaneous healing and healing of zoster-associated pain and post-herpetic neuralgia. Valacyclovir is well tolerated, with convenient dosing frequencies for the treatment of genital herpes or herpes zoster, it also has the option for use as a short course therapy in the episodic treatment of recurrent genital herpes, all of which are important benefits in the management of these conditions.