Famciclovir is the diacetyl ester prodrug of 6-deoxy penciclovir. In order to exhibit its antiviral effects, famciclovir needs to be converted to penciclovir (that takes place following first-pass metabolism in the liver). The indications of famciclovir are similar to acyclovir and valaciclovir. Its safety profile also simulates acyclovir and valacyclovir.