Famciclovir is a nucleoside analog DNA polymerase inhibitor used for the treatment of recurrent cold sores and genital herpes in healthy patients and patients with HIV, and to manage herpes zoster. Famciclovir undergoes rapid biotransformation to the active antiviral compound penciclovir, which has inhibitory activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) and varicella zoster virus (VZV). Famciclovir is hydrolyzed into Desacetylfamciclovir which is hydrolyzed into 6-Deoxypenciclovir. 6-Deoxypenciclovir is then oxidated into Penciclovir. This is transported by drug transporters into the blood then to the infected cell. Viral thymidine kinase phosphorylates penciclovir to a monophosphate form. The monophosphate form of the drug is then converted to penciclovir triphosphate by cellular kinases.Penciclovir triphosphate inhibits the activity of DNA polymerase by competing with its substrate dGTP. Less Viral DNA is transported into the nucleus, therefore, less viral DNA is integrated into the host DNA. Less viral proteins produced, fewer viruses can form.

Famciclovir Pathway References