Antiviral drugs Flashcards
Acyclovir
Inhibits nucleic acid synthesis: competitive inhibitor of dGTP causing termination and trapping the DNA polymerase
Requires metabolic activation to triphosphate form (first one is by viral kinase)
Tx: herpes simplex virus 1 & 2, varicella zoster virus, cytomegalovirus
Poor oral bioavailability
Boceprevir
Prevents cleavage of precursor polypeptides of HCV: inhibits Ns3/4A serine protease
Foscarnet
Inhibition of pyrophosphate cleavage (need to cleave pyrophosphate before linking to the previous component and stops replication)
inhibits DNA/RNA pol and RT
Ganciclovir
Inhibits nucleic acid synthesis: competitive inhibitor of dGTP causing termination and trapping the DNA polymerase
Requires metabolic activation to triphosphate form (first one is by viral kinase)
Tx: herpes simplex virus 1 & 2, varicella zoster virus, cytomegalovirus
Poor oral bioavailability
Oseltamivir
Neuraminidase inhibitor: destroy receptors (sialic residues) recognized by viral hemagglutinin on cell surface
decrease in progeny virions
Viral aggregation at cell surface and reduced virus spread within respiratory tract
Prevents release of influenza A and B virus from infected cell
Ribavarin
Inhibits inosine monophosphate dehydorgenase
Inhibits nucleic acid synthesis: competitively inhibits GTP-dependent 5’ capping of viral mRNA and specifically influenza virus transcriptase activity
Multiple sites of interacting action of GTP-dependent enzymatic processes (some of these may potentiate others)
May enhance viral (lethal) mutagenesis
Converted to triphosphate
Trifluridine
Inhibits nucleic acid synthesis: irreversibly inhibits thymidylate synthase and specific DNA pol
Lesser extent: incorporated in cellular DNA in both infected and uninfected cells (decreasing host DNA synthesis)
Resistance is rare
Tx: HSV- induced keratitis and keratoconjunctivitis
Zanamivir
Neuraminidase inhibitor: destroy receptors (sialic residues) recognized by viral hemagglutinin on cell surface
decrease in progeny virions
Viral aggregation at cell surface and reduced virus spread within respiratory tract
Prevents release of influenza A and B virus from infected cell
Amantadine
Binds M2 protein: Ion channel blocker
Inhibits viral uncoating of Influenza A
Peginterferon Alfa
Inhibits protein synthesis directed by viral mRNA
Signals cell to make antiviral proteins: inhibit translation and other steps in viral replication
Rimantadine
Binds M2 protein: Ion channel blocker
Inhibits viral uncoating of Influenza A
Valacyclovir
Prodrug for acyclovir
Better oral bioavailability
Valganciclovir
Prodrug for ganciclovir
Better oral bioavailability
Abacavir
NRTI
Lamivudine
NRTI
Inhibits nucleic acid synthesis by HBV: competitively inhibits HBV DNA pol
Converted to triphosphate form
Tenofovir Disoproxil
NRTI
Already a monophosphate (nucleotide not a nucleoside)