Antiviral Flashcards
MOA Acyclovir
- guanosine analogue
- required phosphorylation and activation by viral thymidine kinase
- inhibits DNA synthesis by competing with dGTP
- concentrated in viral-infected cells
resistance to Acyclovir
develop due to decrease in viral thymidine kinase
route of administration of Acyclovir
- oral, topical, IV
What is Valacyclovir
- oral pro-drug; converted to acyclovir
- higher bioavailability
DOC: HSV (genital herpes; herpes keratitis)
Acyclovir/Valacyclovir
Toxicity of Acyclovir/Valacyclovir
- Nephrotoxicity with high IV doses
- hydration is important
- safe in pregnancy
MOA: Docosanol (Abreva)
- inhibits viral fusion to host cell plasma membrane so virus can’t get into cell
use of : Docosanol (Abreva)
- OTC for cold sores
- herpex simplex: topical
MOA: of Ganciclovir/Valganciclovir
- Guanosine analogue
- activated by viral kinases
- inhibits DNA polymerase
route of administration of Ganciclovir
- occular implant, oral, or IV
route of administration of Valganciclovir
oral
DOC: CMV
- Ganciclovir/Valganciclovir
DOC: VZV
Acyclovir/valacyclovir
Theraputic use of Ganciclovir/Valganciclovir
- CMV/herpes
- CMV retinitis
- life threatening CMV
contraindication of use with Ganciclovir/Valganciclovir
pregnant women- category C drug
toxicity of Ganciclovir/Valganciclovir
- myelosuppression: leukopenia
- CNS: HA, confusion, sz
MOA: Foscarnet (Foscavir)
- directly inhibits DNA and RNA polymerase, reverse transcriptase
- **does NOT require phosphorylation for activity
DOC: CMV encephalitis
Foscarnet + ganciclovir
treatment of CMV retinitis in ganciclovir resistant
- Foscarnet
- Cidofovir
toxicity of Foscarnet
renal toxicity
route of administration of Foscarnet
IV
MOA of Cidofovir
- inhibits viral DNA polymerase
- phosphorylation to an active drug is independent of viral enzymes
Alternate treatment of HSV
- Ganiclovir/valganciclovir
- Docosanol
- Foscarnet
- Cidofovir
toxicity of cidofovir
dose dependent nephrotoxicity
MOA of Oseltamivir (Tamiflu) and Zanamivir (Relenza)
Neuraminidase inhibitor, block release of virus from cells
DOC: Influenza A and B
- Oseltamivir (Tamiflu): patients > 1 yr
- Zanamivir (Relenza): patients > 7 yrs
route of administration of Oseltamivir (Tamiflu) and Zanamivir (Relenza)
- Oseltamivir (Tamiflu): oral
- Zanamivir (Relenza): inhaler
MOA of Amantadine/Rimantadine
inhibit uncoating of viral RNA within infected host cells, thereby preventing replication
alternate treatment of Influenza A
Amantadine/Rimantadine
MOA of Ribavirin
- guanosine analogue
- phosphorylated by host enzymes
DOC: RSV
Ribavirin
DOC: Hepatitis C
- Interferon alpha2B + Ribavirin (+ boceprevir if needed)
route of administration of Ribavirin
- aerosol
- IV
- oral
toxicity of Ribavirin
- oral: hemolytic anemia
- aerosol: respiratory depression, cardiac arrest
- IV: psychiatric
what do you have to be concerned when prescribing Ribavirin to women
Ribavirin is Teratogenic: category X drug: women should no concieve for at least 6 months after exposure to drug
**occupational exposure problematic
MOA of interferon-alpha2b
- A,B: blocks viral entry
- blocks transcription and translation of mRNA
- blocks viral replication
- blocks viral processing
- blocks viral assembly and release
route of administration of interferon-alpha2b
- IV
- IM
- Subcutaneous
alternate treatment of Hepatitis B
- interferon-alpha2b
- adefovir
- Entecavir
DOC: hepatitis B
Lamivudine
toxicity of interferon-alpha2b
- flu-like symptoms
- CNS: depression and suicide - prescribe antidepressants before initiating interferon therapy
MOA: Boceprevir
- block activity of a serine protease needed for replication of Hepatitis C virus
route of administration of Boceprevir
oral
toxicity of Boceprevir
- drug interaction: inhibitor of CYP3A4
- anemia
route of administration of Lamivudine, Adefovir, Entecavir
oral
MOA of Lamivudine
inhibits hepatitis B polymerase
MOA of adefovir
inhibits Hep B DNA polymerase
toxicity of Adefovir
renal toxicity
MOA of Entecavir
guanosine analogue