Antiviral Drugs Flashcards
How is Acyclovir/Valacyclovir administered?
Oral, topical, IV
What is the MOA for Acyclovir/Valacyclovir?
- Nucleotide analogue
- Requires phosphorylation by viral thymidine kinase
- Inhibits DNA synthesis
- Concentrated in viral-infected cells
What are the uses of Acyclovir/Valacyclovir?
DOC:
VZV (Chicken pox/Shingles)
SAFE IN PREGNANCY
What are toxicities of Acyclovir/Valacyclovir?
- N/V, HA
- Nephrotoxicity (high doses); need to hydrate
How does resistance develop to Acyclovir/Valacyclovir?
Resistance develops due to decrease in viral thymidine kinase
What is the MOA for Docosanol (Abreva)?
Inhibits viral fusion to host cell membrane so that the virus cannot enter cell
What are the uses of Docosanol (Abreva)?
OTC for HSV (cold sores)
How is Ganciclovir/Valganciclovir administered?
Oral, IV, ocular implant
What is the MOA for Ganciclovir/Valganciclovir?
- Nucleoside analogue
- Activated by viral kinases
- Inhibits DNA polymerase
What are the uses for Ganciclovir/Valganciclovir?
DOC:
CMV
CMV retinitis
CMV + Herpes
What are toxicities of Ganciclovir/Valganciclovir?
- Teratogenic!
- Myelosuppresion: leukopenia
- CNS: HA, confusion, seizures
- Nausea, fever, rash
- Hepatotoxicity
What are contraindications to Ganciclovir/Valganciclovir?
Pregnancy
How is Foscarnet administered?
IV
What is the MOA of Foscarnet?
Directly inhibits DNA & RNA polymerase, reverse transcriptase
What are the uses of Foscarnet?
DOC:
CMV encephalitis
(+ ganciclovir)
CMV retinitis
(if ganciclovir resistance)
HSV
(if acyclovir/ganciclovir resistant)
What are toxicities of Foscarnet?
Renal toxicity (renal elimination) – adjust dose and hydrate
What is the MOA for Cidofovir?
- Nucleoside analogue
- Inhibits viral DNA polymerase
What are the uses of Cidofovir?
CMV retinitis (IV) (if ganciclovir resistance)
HSV (IV or topical)
(if acyclovir/ganciclovir resistant)
What are toxicities of Cidofovir?
Renal toxicity (renal elimination) – adjust dose and hydrate
What is the MOA for Oseltamivir (Tamiflu) and Zanamivir (Relenza)?
Neuraminidase inhibitors – block release of virus
What are the uses of Oseltamivir (Tamiflu) and Zanamivir (Relenza)?
DOC:
Influenza A and B (start within 48-72 hours)
How is Oseltamivir (Tamiflu) administered and who is it approved for?
Orally for those over 1 year old
How is Zanamivir (Relenza) administered and who is it approved for?
Nasal or oral inhaler for those over 7 years old
What are toxicities of Zanamivir (Relenza)?
- May worsen respiratory function in COPD
- Bronchospasms in asthmatics
What are toxicities of Oseltamivir (Tamiflu)?
N/V (take with food)
In what population should you avoid prescribing Zanamivir (Relenza)?
Not recommended in those with airway disease
What is the MOA for Baloxavir Marboxil (Xofluza)?
Inhibits DNA synthesis via mRNA
How is Baloxavir Marboxil (Xofluza) administered and who is it approved for?
Orally in single dose for those over 12 years old
What are the uses of Baloxavir Marboxil (Xofluza)?
Influenza A and B (start within 48-72 hours)
How is Ribavirin administered?
Oral, IV, aerosol
What is the MOA for Ribavirin?
- Nucleoside analogue
- Phosphorylated by host enzymes
- Inhibits RNA polymerase and synthesis of GTP
What are the uses of Ribavirin?
DOC:
RSV (aerosol)
What are the toxicities of Ribavirin?
Oral: - Hemolytic anemia (dose dependent) Aerosol: - Respiratory depression, cardiac arrest, hypotension IV: - Psychiatric (SI, depression)
Teratogenic! (Category X drug)
What is a contraindication o Ribavirin?
Women in general (do not conceive for at least 6 months after exposure to drug)
What is the MOA of Tenofovir?
- Nucleoside analogue
- Inhibits HBV DNA polymerase
What are the uses of Tenofovir?
DOC:
Hepatitis B
What is the MOA for Entecavir?
- Nucleoside analogue
- Inhibits HBV DNA polymerase
What are the uses of Entecavir?
2nd DOC:
Hepatitis B
What is the MOA for Lamivudine?
- Nucleoside analogue
- Inhibits HBV DNA polymerase
What are the uses of Lamivudine?
Hepatitis B
What is the MOA for Harvoni?
- Nucleoside analogue
- Inhibits viral NS5B RNA polymerase, blocking replication of HCV and causing termination
What is the MOA for Epclusa?
Inhibits HCV NS5A protein which may prevent replication
What are the uses for Harvoni and Epclusa?
DOC:
Hepatitis C
What are the toxicities of Harvoni and Epclusa?
Fatigue, irritability, HA
What is the DOC for VZV (Chicken pox/Shingles)?
Acyclovir/Valacyclovir
What is the DOC for CMV?
Ganciclovir/
Valganciclovir
What is the DOC for CMV encephalitis?
Foscarnet + Ganciclovir
What is the DOC for CMV retinitis?
Ganciclovir/
Valganciclovir
What are other drug options if there is CMV retinitis resistance to Ganciclovir?
Foscarnet OR Cidofovir
What is the DOC for CMV + Herpes?
Ganciclovir/
Valganciclovir
What is the DOC for Influenza A and B?
Oseltamivir (Tamiflu) and Zanamivir (Relenza)
What is the DOC for RSV?
Ribavirin
What are the top drug choices for Hepatitis B?
DOC:
Tenofovir
2nd DOC:
Entecavir
What is the DOC for Hepatitis C?
Harvoni OR Epclusa