Is an antiviral medication which is used to treat certain viral infections. It acts by inhibiting the production of genetic material (DNA), which is required for reproduction and hence the survival of the virus. Famciclovir itself does not kill the virus, but by stopping it from reproducing the virus is present in lower numbers. The lower numbers mean that the body's immune system can more easily overcome the virus. Famciclovir is used in the treatment of some of the various forms of the herpes virus as well as the virus responsible for causing the symptoms of shingles.