Acyclovir and valaciclovir belong to the group of nucleoside inhibitors of herpes viruses. Acyclovir is converted in the cell into active acyclovir triphosphate by the viral enzyme thymidine kinase. The triphosphate form competitively inhibits the viral DNA polymerase. This leads to a blockade of the viral DNA synthesis and thus of the viral replication. The related drugs ganciclovir and valganciclovir are drug of choice in cytomegalovirus infection.





Population pharmacokinetic parameters for acyclovir:

  • Clearance: Cl= 3,37 * creatinine Cl + 0.41 ml/min/kg
  • Volume of distribution: Vd= 0,69 L/kg
  • Half-life: t1/2= 2,4 h



Acyclovir has excellent oral absorption.


Acyclovir inhibits HSV and varicella zoster virus. 


Acyclovir inactivates the viral DNA polymerase in an irreversible way.