Antivirals Flashcards
What is the difference between acyclovir and valacyclovir?
Val form is a prodrug that gets converted to acyclovir. It is oral, and has a higher bioavailability.
(Why even use acyclovir)
What is required for acyclovir/valacyclovir to be active?
Must be phosphoryltateed and “trapped” in the cell by viral thymidine kinase
How does herpes develop resistance to acyclovir/valacyclovir?
Decreases the amount of/mutates thymidine kinase
The enzyme that phosphorylates and traps the drug
Which nucleotide is acyclovir/valacyclovir an analogue of?
Guanosine
What is the difference between antiviral vs antiretroviral?
Antiretrovirals are for HIV only
Why are acyclovir/valacyclovir such safe drugs?
They are only active once virus-infected cells take them in and phosphorylate them, and then they are trapped in the cell and won’t come back out.
If you see herpes, what drug are you giving?
Acyclovir/valacyclovir
What is the main side effect of acyclovir/valacyclovir?
What can you do to offset it?
Nephrotoxicity in ~high IV~ doses
Hydrate aggressively to prevent this
What is the MOA of docosanol (abreva)?
Inhibits viral fusion to host cell plasma membrane
Docosanol (Abreva) kind of sucks for cold sores. Why is it important?
Because it’s cheap and OTC and might be the only option for some people
(Definitely not the DOC…. that would be acyclovir/valacyclovir becasue it’s herpes)
Ganciclovir and valgancyclovir do the same thing. What is the difference between them?
Valgancyclovir is an oral alternative that is a prodrug with higher bioavailability (just like acyclovir and Val)
(Ganciclovir is oral, IV or ocular implant)
What diseases will be treated by ganciclovir/valgancyclovir?
CMV and herpes
Just wont be as effective for herpes as acyclovir
What can be used as treatment or prophylaxis of CMV and herpes in transplant patients or HIV+ patients?
Ganciclovir
Can we give ganciclovir/valgancyclovir to pregnant women?
No
What are the drugs that can be used for CMV and/or herpes?
Ganciclovir/valgancyclovir
Foscarnet
Cidofovir
What nucleotide is ganciclovir/valgancyclovir an analogue of?
Guanosine
Is ganciclovir/valgancyclovir active when you take it?
No, it must be activated by CMV phospotransferase or Herpes thymidine kinase
How would CMV develop resistance to ganciclovir/valgancyclovir?
Mutate the CMV phosphotransferase that activates the drug