Antivirals Flashcards
(42 cards)
Which drugs block protein synthesis?
Interferon-a
Which drugs block viral uncoating?
Amantidine, rimantidine
Which drugs block release of progency virions?
Oseltamavir, Zanamivir
Which three types of Nucleic Acid synthesis anti-virals are there?
Guanosine analogs, Viral DNA polymerase inhibitors, and Guanine nucleotide synthesis blockers
Which drugs are guanosine analogs?
acyclovir, ganciclovir
Which drugs are viral DNA polymerase inhibitors?
cidofovir, foscarnet
Which drugs are guanine nucleotide synthesis blockers?
Ribavirin
What is the mechanism of oseltamivir/zanamivir? Use?
Inhibit influenza neuraminidase: decr release of progeny virus.
Influenza A and B.
What is the mechanism of acyclovir, famciclovir, and valacyclovir?
Guanosine analogs. Require phosphorylation to be effective - HSV and VZV thymidine kinase. Triphosphate formed by cellular enzymes. Not phosphorylaed in uninfected cells, few adverse effects. Chain termination.
Clinical use of acyclovir, famciclovir, and valacyclovir?
HSV and VZV. Weak against EBV, none against CMV.
- mucocutaneous and genital lesions, and for encephalitis.
- ppx in immunocompromised
- No effect on latent forms.
Which of acyclovir, famciclovir, and valacyclovir has better oral bioavaliability?
Valacyclovir - prodrug
Which antiviral for herpes zoster?
Famcicloivir
Toxicity of acyclovir, famciclovir, and valacyclovir?
Obstructive crystalline nephropathy and acute renal failure if not adequately hydrated.
Mechanism of resistance against acyclovir, famciclovir, and valacyclovir?
Mutated viral thymidine kinase.
What is the mechanism of ganciclovir?
Guanosine analog. 5′-monophosphate formed by a CMV viral kinase.
Triphosphate formed by
cellular kinases. Preferentially inhibit viral DNA
polymerase by chain termination.
What is the clinical use of ganciclovir?
CMV, especially in immunocompromised patients. Valganciclovir, a prodrug of ganciclovir, has
better oral bioavailability.
What is the toxicity of ganciclovir?
Leukopenia, neutropenia, thrombocytopenia, renal toxicity. More toxic to host enzymes than
acyclovir.
Mechanism of resistance against ganciclovir?
Mutated viral kinase
Mechanism of foscarnet?
Viral DNA/RNA polymerase inhibitor and
HIV reverse transcriptase inhibitor. Binds to
pyrophosphate-binding site of enzyme. Does
not require activation by viral kinase.
Clinical use of foscarnet?
CMV retinitis in immunocompromised patients
when ganciclovir fails; acyclovir-resistant HSV.
Toxicity of foscarnet?
Nephrotoxicity, electrolyte abnormalities
(hypo- or hypercalcemia, hypo- or
hyperphosphatemia, hypokalemia,
hypomagnesemia) can lead to seizures.
Mechanism of resistance against foscarnet?
Mutated DNA polymerase.
What is the mechanism of cidofovir?
Preferentially inhibits viral DNA polymerase. Does not require phosphorylation by viral kinase.
What is the clinical use for cidofovir?
CMV retinitis in immunocompromised patients; acyclovir-resistant HSV. Long half-life.
