Oral antivirals revisited in the treatment of herpes zoster: what do they accomplish?

Oral antiviral agents currently represent the most important therapeutic keystone in the treatment of herpes zoster. Three oral antiviral agents are available for the treatment of herpes zoster: acyclovir, its derivative valacyclovir, and famciclovir. Meta-analysis of published data has shown that oral acyclovir significantly reduces various herpes zoster-related symptoms as well as the duration, intensity and prevalence of zoster-associated pain (ZAP). However, this drug does not influence postherpetic neuralgia. The newer agents famciclovir and valacyclovir exhibit a better oral bioavailability than acyclovir. These agents have demonstrated similar efficacy to acyclovir with ZAP and they require less frequent administration. When initiated within 72 hours, oral antiviral therapy of herpes zoster is beneficial in selected, elderly immunocompetent patients, reducing the duration and intensity of ZAP and providing more rapid skin lesion healing. Oral antivirals are also of benefit in immunocompromised patients with uncomplicated herpes zoster. However, signs of cutaneous and visceral dissemination should be monitored; if signs occur, intravenous antiviral therapy is indicated.