Antivirals Flashcards
Acyclovir (zovirax) MOA
Guanosine analogue.Inhibits DNA synthesis by competing with dGTP. Terminates the chain due to lack of 3 prime hydroxyl. Requires phosphorylation by viral thymidine kinase.
Herpes DOC
Acyclovir
Acyclovir resistance
decrease viral thymidine kinase so the drug can’t be activated by phosphorylation.
Acyclovir kinetics
oral/IV/topical. Short half life. Concentrated (trapped) in viral cells. Excreted by the kidney
Valcyclovir
pro-drug with higher bioavailability. Eventually converted into acyclovir.
Acyclovir uses
genital herpes, oral herpes, herpes keratitis, encephalitis, prophylaxis in organ transplants.
Acyclovir toxicity
nephrotoxicity with high IV doses (decreased with hydration), nausea/vomiting, HA. Safe to use during pregnancy.
Docosanol (Abreva) MOA
Inhibits viral fusion
Docosanol (abreva) uses
OTC topical preparation for cold sores
Ganciclovir/valganciclovier MOA
Guanosine analogue activated by viral kinases. inhibits DNA polymerase. Less active and more toxic than Acyclovir.
Ganciclovir kinetics
Ocular implant, IV, Oral.
valganciclovir kinetics
Oral prodrug.
Ganciclovir uses
CMV/Herpes in immunocompromised, CMV retinitis, Life threatening CMV infections.
Ganciclovir toxicity
myelosuppression (neutro, thrombo, leuko) especially when used with zidovudine for HIV. Severe HA, confusion and seizures.
Foscarnet (foscvir) MOA
directly inhibits DNA/RNA polymerase and reverse transcriptase. No need for phosphorylation (good for use in resistant strains).
Foscarnet uses
Back up for HSV/CMV that are resistant to acyclovir or ganciclovir.
Foscarnet toxicity
Renal, adjust the dose and hydration.
Cidofovir (vistide) MOA
Cytosine analogue that inhibits viral DNA polymerase. Phosphorylated independent of viral enzymes.
Cidofovir uses
Back up for resistant strains of CMV and HSV.
Cidofovir toxicity
Dose dependent nephrotoxicity (hydration).
Osteltamivir (tamiflu)/Zanamivier (Relenza) MOA
Neuraminidase inhibitor. Blocks the release of the virus from the host cell.
Osteltamivir (tamiflu)/Zanamivier (Relenza) uses
Active against influenza A and B. Has to be used within 48 hours of symptom onset.
Osteltamivir (tamiflu) administration
Oral. approved for >1 year of age. Also used for the bird flu.
Osteltamivir (tamiflu) toxicity
nausea and vomiting (take with food)
Zanamivier (Relenza) administration
nasal/oral inhaler. approved for >7 years of age.
Zanamivier (Relenza) toxicity
Worsens COPD and asthma. Shouldn’t be given if patient has any airway disease.
Amantadine (symmetrel)/Rimantadine (flumadine) MOA
inhibits viral uncoating
Amantadine (symmetrel)/Rimantadine (flumadine) uses
prophylactic or symptomatic treatment of influenza A. Rarely used due to rapid development of resistance.
Ribavirin (virazole) MOA
Guanosine analogue that inhibits RNA polymerase and synthesis of GTP. Independent of viral kinases for phosphorylation.
Ribavirin (virazole) toxicity
hemolytic anemia, respiratory depression, cardiac arrest, IV use cause psychiatric issues. TERATOGENIC! even with occupational exposure.
RSV DOC
Ribavirin (virazole)
Ribavirin (virazole) uses
DOC for RSV. Also used to treat HCV along with interferon.
Interferon-alpha2b (intron-A) MOA
Blocks EVERYTHING (entry, transcription, translation, replication, processing, assembly and release). Given IV/IM.
PEG-interferon
Interferon-alpha2b (intron-A) that is long lasting and given as a depot prep once a week.
Interferon-alpha2b (intron-A) uses
HCV with ribavirin and chronic HBV.
Interferon-alpha2b (intron-A) toxicity
Flu-like symptoms, CNS depression and suicide (MUST prescrive with an antidepressant), hematologic, cardiac (hypotension and edema).
Boceprevir (victrelis) MOA
Blocks serine proteases needed for replication of HCV.
Boceprevir (victrelis) uses
Oral. Can be added to interferon and ribavirin to treat HCV.
Boceprevir (victrelis) toxicity
ihibitor of CYP3A4, exacerbates anemia, neutropenia and fatigue associated with interferon/ribavirin treatment.
HBV DOC
Lamivudine.
Lamivudine MOA
inhibits HBV polymerase (reverse transcriptase inhibitor)
Lamivudine use
DOC for chronic HBV can also treat HIV. Oral. few side effects.
Adefovir MOA
inhibits HBV DNA polymerase.
Adefovir toxicity
renal toxicity
Entecavir MOA
Guanosine analogue. Inhibits HBV DNA polymerase.