Antivirals Flashcards
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.
What is the toxicity of cidofovir?
Nephrotoxicity (coadminister with probenecid and IV saline to decr toxicity).
What is the mechanism of ribavirin?
Inhibits synthesis of guanine nucleotides
by competitively inhibiting inosine
monophosphate dehydrogenase.
What is the clinical use of ribavirin?
Chronic HCV, also used in RSV
What is the toxicity of ribavirin?
hemolytic anemia, severe teratogen
What is the mechanism of Simeprevir?
HCV protease inhibitor, prevents viral replication
What is the clinical use of simeprevir?
chronic HCV in combo w/ ribavirin and peg-interferon-a
Cannot be used as monotherapy
What is the toxicity of simeprevir?
Photosensitivity rxn, rash
What is the mechanism of sofosbuvir?
Inhibits HCV RNA-dependent RNA polymerase acting as a chain terminator
Clinical use of sofosbuvir?
chronic HCV in combo w/ ribavirin and peg-interferon-a
Cannot be used as monotherapy
Toxicity of sofosbuvir?
Fatigue, headache, nausea
what is IFN-B given for?
MS
What is IFN-Y given for?
chronic granulomatous disease
What is IFN-A given for?
HCV/HBV, kaposi, hairy cell, condyloma accuminatum, RCC, malignant melanoma
Infection control (general): autoclave
pressurized steam at >120C. May be sporicidal.
Infection control (general): alcohols
Denature protein and disrupt cell membranes. Not sporocidal.
Infection control (general): chlorhexidine
Denature protein and disrupt cell membranes. Not sporocidal.
Infection control (general): hydrogen peroxide
Free radial oxidation. Sporicidal.
Infection control (general): iodine and iodophors
Halogenation of DNA, RNA and proteins. May be sporicidal.
