prodrugs
only become pharmaceutically active once they are metabolized within the cell, and therefore exact mechanism of action is not always entirely clear
pleconaril
Attachment Antagonists
–Prevents attachment, exposure of RNA in picornaviruses
•Mainly Enterovirus and Rhinovirus, potentially Hepatitis A virus and Poliovirus
enfuvirtid
early inhibitors
–Binds to gp41 and inhibits HIV membrane fusion
amantadine and rimantadine
uncoating inhibitors
interfere with Influenza virus protein M2 and prevent physiological changes needed to result in viral uncoating
arildone
–Binds to a stabilizes the Poliovirus capsid, preventing the uncoating, also effective against HSV-2 (mechanism unknown)
uncoating inhibitor
nucleic acid synthesis inhibitors
•Prodrugs converted into triphosphate nucleotide analogs and inhibits DNA Polymerase
Converted intracellularly by viral thymidine kinase, effective against EBV, CMV, HSV, VZV
Acyclovir
Valaciclovir (“esterfied” acyclovir)
Ganciclovir
Penciclovir
nucleic acid synthesis inhibitor
Converted intracellularly by cellular                                           kinases, effective against HSV and VZV
Adenosine arabinoside
nucleic acid synthesis inhibitor
sofosbuvir
–NS5B (RNA Polymerase) inhibitor in HCV that prevents viral RNA replication
nucleic acid synthesis inhibitors
ribavirin
–RNA analog that binds and prevents RNA synthesis in Hantavirus, HCV, and RSV
nucleic acid synthesis inhibitors
NRTI
•__N__ucleoside analog __Reverse-T__ranscriptase __I__nhibitors
–Nucleoside analogs that prevent DNA synthesis via reverse transcriptase
effective against HIV
•Azidothymidine/Zidovudine
•Tenofovir
Nucleic acid synthesis inhibitors (NRTI)
effective against HBV
entecavir
nucleic acid synthesis inhibitors
NRTI
effective against both HIV and HBV
Lamivudine
Nucleic acid synthesis inhibitors
NTRI
Effective against HBV and HSV
adefovir
nucleic acid synthesis inhibitors
NRTI
fomivirsen
–Antisense nucleic acids that bind to mRNA and prevent translation in Cytomegalovirus
protein synthesis inhibitors
protein synthesis inhibitors
Some viruses translate many/all of their proteins at once and then utilize post-translational proteases to cleave the individual proteins apart from one another to make the mature viral proteins needed for assembly
•Darunavir and Fosamprenavir
–Protease inhibitors specific to enzymes in HIV that prevent formation of mature viral proteins
protein synthesis inhibitors
•Boceprevir and Telaprevir
–Protease inhibitors specific to enzymes in HCV that prevent formation of mature viral proteins
protein synthesis inhibitors
ledipasvir
–NS5A inhibitor in HCV that prevents assembly of the mature viral proteins
assembly inhibitors
release inhibitors
In the Influenza virus, Hemagglutinin binds to siliac acid on the host cell to attach and Neuraminidase cleaves this bond to allow the virus to detach from the host cell
neuraminidase
release inhibitors
prevents the virus from being able to detach from the host cell and spread to new cells
•Oseltamivir (Tamiflu) and Zanamivir (Relenza)
–Neuarminidase inhibitors to prevent the spread of newly synthesized Influenza viruses
release inhibitors
antiviral resistance
High viral loads with multiple strains, fast reproduction rates, and little to no proof-reading/repair leads to very high mutation rates in viruses, often making antiviral medication ineffective
combination treatment -HAART
Highly active antiretroviral therapy combines a “cocktail” of antiviral medication to combat HIV to prevent the rapidly-mutating HIV from developing resistance to the drugs
HAART
Highly active antiretroviral therapy
antiretroviral drugs (ART), antiretrovirals (ARVs), or anti-HIV drugs, has proven to be effective at reducing the onset of AIDS and mortality rate of those affected with HIV