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Zovirax (ACYCLOVIR)

Ligand Pharms · FDA-approved approved Small molecule Verified Quality 80/100

Acyclovir works by mimicking a building block of DNA to prevent the herpes virus from replicating.

Zovirax (Acyclovir) is a small molecule drug developed by Valeant Bermuda and currently owned by Ligand Pharmaceuticals. It targets the enzyme purine nucleoside phosphorylase and works as a nucleoside analog DNA polymerase inhibitor to treat various herpes simplex virus infections. Zovirax has been FDA-approved since 1982 for multiple indications, including encephalitis, genital herpes, and herpes zoster. The drug has a bioavailability of 22% and a half-life of 2.5 hours. It is available as a generic medication from multiple manufacturers.

At a glance

Generic nameACYCLOVIR
Also known asaciclovir
SponsorLigand Pharms
Drug classHerpes Simplex Virus Nucleoside Analog DNA Polymerase Inhibitor [EPC]
TargetPurine nucleoside phosphorylase
ModalitySmall molecule
Therapeutic areaImmunology
PhaseFDA-approved
First approval1982

Mechanism of action

Mechanism of Antiviral Action:. Acyclovir is synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types (HSV-1), (HSV-2), and varicella-zoster virus (VZV).The inhibitory activity of acyclovir is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV. This viral enzyme converts acyclovir into acyclovir monophosphate, nucleotide analogue. The monophosphate is further converted into diphosphate by cellular guanylate kinase and into triphosphate by number of cellular enzymes. In vitro, acyclovir triphosphate stops replication of herpes viral DNA. This is accomplished in ways: 1) competitive inhibition of viral DNA polymerase, 2) incorporation into and termination of the growing viral DNA chain, and 3) inactivation of the viral DNA polymerase. The greater antiviral activity of acyclovir against HSV compared with VZV is due to its more efficient phosphorylation by the viral TK.

Approved indications

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Patents

PatentExpiryType

Primary sources

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SourceUsed for
FDA labelMechanism, indications, dosing, boxed warnings, drug interactions
ClinicalTrials.govTrial enrolment, design, endpoints, results
FDA Orange BookPatents + exclusivity

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