Antivirals I Flashcards
What are the main anti-HSV and anti-VSV agents?
Acyclovir, Famciclovir, and Valacyclovir. All guanosine analogs.
What is the mechanism of action of the guanosine analogs?
They inhibit DNA polymerase and incorporate into viral DNA.
What are the other anti-HSV and anti-VSV agents?
Docosanol and Trifluridine.
What is Docosanol?
A 22 carbon alcohol that inhibits fusion of the viral envelop with the host cell membrane.
What is Trifluridine?
A fluorinated nucleoside that prevents both viral and host DNA synthesis.
What is Trifluridine used for?
Acyclovir resistant HSV.
What are the anti-CMV agents?
Ganciclovir, Valganciclovir, Cidofovir, and Foscarnet.
What is Cidofovir?
A cytosine analog. It’s di-phosphorylation is independent of viral kinases.
What is the drug of choice for CMV and why?
Valganciclovir, because it is orally active.
What is the treatment for HBV comprised of?
Five oral nucleoside/nucleotide analogs that are inhibitors of HBV DNA polymerase.
What is the treatment regimen for HBV?
HBV is treated sequentially (as opposed to HCV which responds best to combination therapy).
What are the anti-HBV agents?
Entecavir, Tenofovir, Adefovir, Lamivudine, and Telbivudine.
What is Entecavir?
A guanosine analog.
What is the best anti-HBV agent and its contraindication?
Tenofovir is the best anti-HBV agent, but it is contraindicated in renal insufficiency.
What else can be used used anywhere in the HBV treatment sequence?
PEG-IFN.
What were the only anti-HCV agents before the direct acting agents were discovered?
PEG-IFN and Ribavirin.
What is Ribavirin?
A guanosine analog that interferes with RNA metabolism required for viral replication. It works via multiple mechanisms.
What is the MOA of IFN?
Inhibits RNA and protein synthesis and destroys both the virus and infected host cells (a major side effect).
What is PEP?
Polyethylene glycol. It increases the half-life of IFN to one injection per week rather than daily.
What are the direct acting anti-HCV agents?
Drugs ending with the suffixes “buvir”, “previr”, or “asvir”.
What is NS3/4 A?
A HCV serine protease that catalyzes the cleavage of the HCV polyprotein into mature HSV. Is targeted by the “previr” drugs.
What is NS5B?
A HCV RNA dependent RNA polymerase. Is targeted by “buvir” drugs.
What is NS5A?
A HCV replicase. It is inhibited by the “asvir” drugs.
What is the MOA of drugs ending in “buvir”?
They target HCV NS5B.
What is the MOA of drugs ending in “previr”?
They target HCV NS3/4 A.
What is the MOA of drugs ending in “asvir”?
They target HCV NS5A.
What is the most common drug combination for HCV?
Ledipasvir and Sofosbuvir.
What are the anti-influenza agents?
The Adamantanes and Neuraminadase inhibitors.
What are the Adamantanes?
Amantadine and Rimentadine.
What is the MOA of the Adamantanes?
They block viral release by targeting the M2 protein.
What are the Adamantenes ineffective against?
H1N1, H3N2, and all influenza B strains.
What are the Neuraminadase inhibitors?
Zanamir (inhalation), Oseltamivir, and IV Peramiver.
What is the MOA of Neuraminadase inhibitors?
They block viral release.
What is an adverse side effect of IFN as well as a contraindication?
IFN can cause autoimmune reactions and is contraindicated in hyperbilirubinemia due to hepatic damage.
