Exam 3 - Smith - Antivirals Flashcards
T/F - Viral genetic material can either be DNA-encoded or RNA-encoded.
TRUE
What are antigens?
Proteins expressed not he surfaces of viruses that are recognized by host’s immune system
What is antigenic drift?
Antigens on newly formed viruses may evolve one or more mutations that prevent a host’s immune systems from recognizing the virus
What are antigenic shifts?
Significant and/or frequent enough, resistance develops which may lead to larger scale viral epidemics
These drugs inhibit what?
Acyclovir Valaclovir Famcyclovir Penicyclovir Ganciclovir Foscarnet
DNA POLYMERASE
*Used on DNA-encoded viruses
What drug inhibits viral uncoating M2 protein?
Amantadine
*RNA-encoded viruses
What drug inhibits viral RNA polymerase to prevent translation into mRNA?
Ribavarin
What drugs are neuroaminidase inhibitors?
Zanamivir (Relenza)
Oseltamivir (Tamiflu)
Tell me the main 3 types of the Herpes Simplex Virus?
1 - Oral herpes
—Trigeminal ganglia
—Fever blisters/cold sores
2 - Genital herpes
—Sacral ganglia
—Genitals, inner thighs, buttocks
3 - Varicella-Zoster
T/F - HSV may spread to the genitalia from the mouth and vice-versa.
TRUE
T/F - 2/3rds of population are HSV-1 positive.
TRUE
T/F - Over 400 million people worldwide are HSV-2 positive.
TRUE
Tell me the 8 types of HHV (HSV).
1 - Oral
2 - Genital
3 - VSV (chicken pox and shingles)
——————————————————
4 - EBV
5 - CMV
6 - Roseola
7 - Associated with HHV-6
8 - Kaposi’s Sarcoma
T/F - 1/3 of people will develop shingles at some point in their life.
TRUE
T/F - VZV’s primary infection is chickenpox, and VZV’s reactivation/recurrent infection is shingles.
TRUE
For how long is chicken pox contagious?
1-2 days pre-rash until all lesions are gone (about 7-10 days total)
When does shingles typically present itself?
Later in life
OR
During immunocompromised situations
What factors can cause a latent infection to become active again?
Stress
Fatigue
Sun exposure
Surgery
Fever
Menstrual periods
Immunocompromised
Difference b/t canker sore and cold sore.
Canker
- Cause unknown
- Inside mouth and on gingiva
- White, yellow, gray center, bright read border
- Single or in groups
- NOT CONTAGIOUS
Cold Sore -HSV -On or around lips, OUTSIDE of mouth -Red, fluid-filled, typically in groups -CONTAGIOUS —Avoid skin-to-skin contact with an active cold sore blister
T/F - Pts must ALWAYS hydrate well while on any -cyclovir drug to avoid crystalline nephropathy.
TRUE
Acyclovir is mostly prescribed for what?
HSV-1, and HSV-2
-Oral, IV, or topical
Tell me about valacyclovir.
Metabolized to acyclovir which equals 5x greater than oral acyclovir
-Oral
What drug is used for VZV?
Famcyclovir
Tell me about famcyclovir.
Metabolized pencyclovir which equals higher intracellular concentrations that oral acyclovir
-Oral only
Efficacy for VZV?
Famcyclovir>/= valacyclovir»>acyclovir
T/F - Penicyclovir is only used topically for either oral or genital HSV-1/HSV-2.
TRUE
T/F - All -cyclovir drugs share cross-resistance.
TRUE
*If resistant to one, you will be resistant to all
**All are renally cleared, so drink plenty of water
Which antiviral is IV only?
Gancyclovir
- Contraindicated in pregnancy (teratogenic, mutagenic)
- Contraindicated in men who wish to stay fertile
- Used to avoid cytomegalovirus
Tell me about Foscarnet.
IV only
SAFER than gancyclovir
Useful in acyclovir or gancyclovir-resistant HSV or CMV infections
How does Foscarnet work?
- Selectively inhibits VIRAL DNA POLYMERASE ENZYMES (NOT KINASES)*
- Nephrotoxic, so be careful
T/F - Viral kinases can mutate leading to resistance to cyclovir drugs.
TRUE
How does Tamiflu (Oseltamivir) work?
Neuroaminidase inhibitor
-Prevents cleavage of cell receptor keeping virus particle bound to host
-Can be used for prophylaxis or tx of influenza A and B viruses
T/F - Tamiflu prevent release of viral progeny from host cells, this stops viral spread, and allows the body to due its work.
TRUE
T/F - Tamiflu is active against both Influenza A and B.
TRUE
T/F - When a 5 day course of Tamiflu is initiated w/in 48 hours from onset of flu-symptoms, the duration of flu symptoms are decreased by up to 1-2 days.
TRUE
*Avoid alcohol
What other drug is like Tamiflu?
Relenza
How is Relenza different from Tamiflu?
Relenza can be inhaled or nose dropped
*Relenza is contraindicated for asthma, COPD, or allergies to MILK
What is Amantadine?
Anti-Parkinson’s drug that is also used as an antiviral for influenza A, a long time ago
-Used in 3rd world countries often b/c of affordability
T/F - Influenza A is nearly 100% resistant to Amantadine.
TRUE
-Almost never used b/c it only works with a few pts
