Flashcards in 4/25 Antivirals Deck (45)
name 2 neuraminidase inhibitors
MoA of Oseltamivir or Zanamivir
Inhibits influenza neuraminidase -> decrease release of virus
difference between Oseltamivir or Zanamivir?
Oseltamivir – oral drug
Zanamivir – inhaler; limited use in young children or patients who are unable to follow instructions
indications for Oseltamivir or Zanamivir?
influenza A/B (trmt/prevention)
name nucleotide analogs (at least 5)
MoA of Ribavirin?
nucleotide analog that inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase (prevents ribosomes from binding to viral RNA)
half-life of Ribavirin?
long half-life (stored in RBC and released over days)
Indications for Ribavirin?
ADRs of using ribarivin?
What are 2 alternate drugs that are within the same class as acyclovir?
MoA of Acyclovir?
Guanosine analog; phosphorylated by HSV/VZV–TK and subsequently phosphorylated by host enzymes to form a triphosphate
preferentially inhibits viral DNA polymerase chain termination (virus must be actively replicating; NO effect on latent forms)
Why should you be be considered when you prescribe acyclovir?
does the patient have renal failure?
renally excreted, therefore dose must be adjusted for patients with renal insufficiency
compare oral bioavailability between acyclovir and the 2 alternate drugs that are within the same class
acyclovir: not great
valacyclovir: oral pro-drug of acyclovir; better oral bioavailability
famciclovir: best oral bioavailability
Indications for acyclovir? valacyclovir?
HSV (mucocutaneous and genital lesions, encephalitis, pregnant women/neonatal, prophylaxis in immunocompromised patients) = oral acyclovir or valacyclovir
VZV (healthy, immunocompromised, pregnant women/neonates) = valacyclovir*, acyclovir
VZV, uncomplicated = famciclovir
CMV – weak activity
when would you normally prescribe famciclovir?
VZV (according to first AID)
Mechanism of resistance for Acyclovir et al?
Mutated viral TK
(common among immunodeficient patients, eg AIDs patients, who receive ACV for prolonged periods)
Side effect of Acyclovir et al?
What can you do to prevent this?
Nephropathy due to obstructive crystalline formation; can progress to acute renal failure if not adequately hydrated
What is an alternate drug that is within the same class as Ganciclovir?
What is the mxn of ganciclovir?
Guanosine analog that is converted to 5MP by CMV viral kinase and subsequently phosphorylated by host enzymes to form a triphosphate
preferentially inhibits viral DNA polymerase
why is ganciclovir more toxic than acyclovir?
more toxic to host enzymes than acyclovir because it can actually be incorporated into DNA, thereby inhibiting HOST kinases and DNA polymerases
What is valganciclovir?
valganciclovir is a pro-drug of ganciclovir; better oral bioavailability
Indications for ganciclovir?
mechanism of resistance for ganciclovir?
UL97 mutated CMV DNA polymerase or lack of viral kinase
side effects of ganciclovir?
Bone marrow suppression
What is Foscarnet?
Pyro"fos"phate inhibitor that binds to the pyrophosphate-binding site of DNA polymerase; does not require activation by viral kinase
Indication for Foscarnet?
Ganciclovir-resistant CMV retinitis
Mxn of resistance for Foscarnet
mutated DNA polymerase
ADR for foscarnet?
Sequesters divalent cations --> Hypo-Ca, Hypo-PO4, Hypo-Mg
Mxn of Cidofovir?
Nucleotide analog that inhibits viral DNA polymerase; does not require activation by viral kinase
10-100x more active against CMV in vitro
Half-life of Cidofovir?
Indications for Cidofovir?
Pox viruses (small pox, vaccinia, monkeypox)
Mxn of resistance for Cidofovir?
Mutated DNA polymerase
Side effect of Cidofovir? ways to prevent it from happening?
Nephrotoxicity (coadminister with probenecid and IV saline to toxicity)
What is Interferon α and its mechanism of action?
glycoproteins with anti-viral and anti-tumor properties; inhibits viral replication and promotes cytotoxic T cell and NK cell activity
Indications for Interferon α?
Hep B, C
Hairy cell leukemia
Side effects of Interferon α?
What are Boceprevir and Telapravir?
Protease inhibitor that forms a covalent bond with NS3 protease and prevents it from cleaving the HCV polyprotein into functional viral proteins
Indications for Boceprevir and Telapravir?
HCV – one very specific type only
ADR for Boceprevir and Telapravir?
Boceprevir – anemia, pancytopenia
Telapravir – anemia, pruritus, skin rash
Drugs for resistant strains
Valganciclovir –prophylaxis in immunocompromised hosts
Drugs for resistant strains