Comparison between famciclovir and valacyclovir for acute pain in adult Japanese immunocompetent patients with herpes zoster.

Famciclovir is a guanine analog antiviral drug used commonly for herpes zoster. Efficacy of famciclovir treatment has been reported to be comparable to valacyclovir treatment. Both of these medications reduce the time to complete cessation of zoster-associated pain including post-herpetic neuralgia, as compared to acyclovir.