Anti Viral Flashcards
What is the mechanism of action for oseltamivir and zanamivir?
Inhibit influenza neuraminidase → ↓ release of progeny virus.
What is the clinical use of oseltamivir and zanamivir?
Treatment and prevention of influenza A and B. Beginning therapy within 48 hours of symptom onset may shorten duration of illness.
What is the mechanism of action for baloxavir?
Inhibits the “cap snatching” (transfer of the 5’ cap from cell mRNA onto viral mRNA) endonuclease activity of the influenza virus RNA polymerase → ↓ viral replication.
What is the clinical use of baloxavir?
Treatment within 48 hours of symptom onset shortens the duration of illness.
What is the mechanism of action for remdesivir?
Prodrug of an ATP analog. The active metabolite inhibits viral RNA-dependent RNA polymerase and evades proofreading by viral exonuclease (ExoN) → ↓ viral RNA production.
What is the clinical use of remdesivir?
Recently approved for the treatment of COVID-19 requiring hospitalization.
What is the mechanism of action for acyclovir, famciclovir, and valacyclovir?
Guanosine analogs. Monophosphorylated by HSV/VZV thymidine kinase and not phosphorylated in uninfected cells → few adverse effects. Triphosphate formed by cellular enzymes. Preferentially inhibit viral DNA polymerase by chain termination.
What are the clinical uses of acyclovir, famciclovir, and valacyclovir?
- No activity against CMV because CMV lacks thymidine kinase necessary to activate guanosine analogs.
- Used for HSV/VZV-induced mucocutaneous and genital lesions as well as for encephalitis.
- Prophylaxis in immunocompromised patients.
- Prophylaxis in immunocompetent patients with severe or recurrent infection.
- No effect on latent forms of HSV and VZV.
- Valacyclovir, a prodrug of acyclovir, has better oral bioavailability.
- For herpes zoster, use famciclovir.
What are the adverse effects of acyclovir, famciclovir, and valacyclovir?
Obstructive crystalline nephropathy and acute kidney injury if not adequately hydrated.
What is the mechanism of resistance for acyclovir, famciclovir, and valacyclovir?
Mutated viral thymidine kinase.
