NCIt definition : The sodium salt form of acyclovir, a synthetic analog of the purine nucleoside, guanosine,
with potent antiviral activity against herpes simplex viruses type 1 and 2, varicella-zoster
virus and other viruses of the herpesvirus family. After conversion in vivo to the
active metabolite acyclovir triphosphate by viral thymidine kinase, acyclovir competitively
inhibits viral DNA polymerase by incorporating into the growing viral DNA chain and
terminating further polymerization.;