Summary Antivirals

Antiviral Chemotherapies

DNA Polymerase Inhibitors (DNA Viruses)

 Aciclovir:
 Nucleoside analogue
 Selective for viral DNA Polymerases
 Treatment for Herpes 1 and 2
 Phosphorylated by thymidine kinase both viral (mono) and cellular (di and tri)
as Aciclovir triphosphate is active form
 Poor oral availability and solubility
 Prodrug forms created Valaciclovir (L-Valine added)
 Competitive
 Penciclovir:
 Longer duration
 Poor solubility so prodrug Famciclovir
 Cidofovir:
 For viruses lacking thymidine kinase
 Monophosphate analogues
 Phosphonate is more stable than phosphate (mimics deoxycytidine
monophosphate)
 Extremely polar so poor bioavailability
 Idoxuridine and Trifluridine:
 Nucleoside analogues elaborated by cellular kinases
 Not as selective so more side effects

Nucleoside and Non-nucleoside Reverse Transcriptase Inhibitors (RNA Based Viruses)

 AZT and Lamivudine (nucleoside):
 Active in triphosphate form by cellular kinases
 Enzymatically converted into adenosine nucleobases in situ
 Competitive inhibitors
 Multiple side effects
 Nevirapine and Delavirdine (Non-nucleoside):
 Reversible non-competitive binding to allosteric site
 Mutation of allosteric site gives resistance

HIV Protease Inhibitors

 Apartyl proteases

Flu Virus

 Haemagglutinin:
 Viral glycoprotein
 Curial for absorption into cell
 Binds to glycol-conjugates containing sialic acid on host cell
 Neuraminidase:
 Viral protein cleaves sialic acid removing it from glycoproteins
 Blocking neuraminidase prevents virus infecting the cell


Neuraminidase