4 Antivirals Flashcards
What is antigenic drift?
Some antigens may become mutated during reproduction keeping prevent the immune system from recognizing the virus. (passively evading detection)
What is antigenic shift?
A large change in the expression of surface antigens on a virus to evade the host immune system. (actively evading detection)
Does antigen drift or shift cause epidemics?
Antigenic shift
What are the four target sites of action of antivirals?
Inhibition of 1) DNA Polymerase, 2) M2 protein, 3) RNA Polymerase, 4) Neuraminidase
What antiviral drugs target DNA polymerase?
Famcyclovir, Acyclovir, Penicyclovir, Valacyclovir, Ganciclovir, and Foscarnet (FAPVGF)
What does Amantadine target in the virus?
M2 protein which aids in the uncoating of the virus.
What does Ribavarin target?
RNA polymerase to prevent translation of viral proteins
What two antiviral drugs target neuraminidase?
Oseltamivir and Zanamivir (OZ)
Where does HSV-2 tend to reside during remission?
In the Sacral Ganglia at the base of the spine
What virus causes chickenpox and shingles?
varicella zoster virus (VZV)
When is chicken pox contagious?
1-2 days PRIOR to having a rash
Define immunosenescence
age-related decline in immune function
that increases risk of infection
Where do canker sores appear vs. cold sores?
- canker sores appear in the mouth and on the gingiva
- cold sores are outside the mouth, on the lips, etc
Are canker sores contagious?
No
What are three go-to drugs to treat HSV and VZV?
Acyclovir primarily for HSV, Valacyclovir for both, and Famciclovir for VZV
Why do patients taking antivirals for HSV or VZV need to drink plenty of water?
They can cause crystalline nephropathy by accumulating in the kidneys
What drug is approved for prophylaxis and treatment of Cytomegalo virus?
Gancyclovir
What drug inhibits spermatogenesis and shouldn’t be prescribed to pregnant patients or pts that want to have kids?
Gancyclovir
If the HSV or CMV infection is resistant to acyclovir or gancyclovir, what do you prescribe?
Foscarnet
What drug is used topically to treat HSV sores?
Peniciclovir
How exactly does Acyclovir work?
It undergoes 3 phosphorylations before inserting into the viral DNA where it blocks elongation
_________ is 10x more potent against HSV-1 and HSV-2 than against VZV.
Acyclovir
Why can Foscarnet work on viruses that are resistant to acyclovir and gancyclovir?
Because it doesn’t require viral kinases to be activated
What drug would you use to treat Influenza A and B viruses?
Oseltamivir (Tamiflu)
What happens to the course of infection of Tamiflue isn’t given within the first 24-72 hours?
It increases the time of sickness by 1-2 days
What drug is used to treat and prophylaxis of Influenza A and B viruses?
Zanamivir
What are contraindications for using Zanamivir?
severe asthma, COPD, or allergies to mile proteins
What are contraindication for prescribing Amantadine?
Renal impairment, epilepsy, closed angle glaucoma, and pregnant pts
What has a near 100% resistance to Amantadine?
Influenza B virus
Can you use Amantadine for Influenza A infections?
yes, but not with Influenze
