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Acyclovir
Intended Dose:
Drug Pharmacology

Purine nucleosides
A guanosine analog antiviral drug that acts as an antimetabolite. Aciclovir is used for the treatment of herpes simplex virus infections, varicella zoster (chickenpox) and herpes zoster (shingles).
For the treatment and management of herpes zoster (shingles), genital herpes, and chickenpox.
  • Bell's Palsy
  • Chickenpox
  • Encephalitis, Herpes Simplex
  • Herpes Simplex Infection
  • Herpes Zoster
  • Herpes simplex of the oral-labial
  • Herpes simplex type I reactivation
  • Infections, Cytomegalovirus
  • Recurrent Genital Herpes (RGH)
  • Recurrent Herpes Labialis
  • VZV re-activation
  • Acute Genital herpes
  • Acute Herpes labialis
  • Severe Genital herpes
 
Aciclovir (INN) or acyclovir (USAN, former BAN) is a synthetic deoxyguanosine analog and it is the prototype antiviral agent that is activated by viral thymidine kinase. The selective activity of aciclovir is due to its affinity for the thymidine kinase enzyme encoded by HSV and VZV. EC50 value of acyclovir against clinical herpes virus isolates was 1.3 μM (range: < 0.56 to 3.3 μM).
Viral (HSV-1, HSV-2 and VZV) thymidine kinase converts aciclovir to the aciclovir monophosphate, which is then converted to the diphosphate by cellular guanylate kinase, and finally to the triphosphate by phosphoglycerate kinase, phosphoenolpyruvate carboxykinase, and pyruvate kinase. Aciclovir triphosphate competitively inhibits viral DNA polymerase and competes with the natural deoxyguanosine triphosphate, for incorporation into viral DNA. Once incorporated, aciclovir triphosphate inhibits DNA synthesis by acting as a chain terminator. One may consider aciclovir to be a prodrug as it is metabolized to more active compounds. Aciclovir is selective and low in cytotoxicity as the cellular thymidine kinase of normal, uninfected cells does not use aciclovir effectively as a substrate.