Flashcards in antiviral pharmacology Deck (13):
what is the mechanism of action of acyclovir?
competes with deoxyGTP for viral DNA polimerase and becomes incorporated into the replicating viral DNA chain ==> causes DNA SYNTHESIS TERMINATION
what type of anti-viral drug is monophosphorilated by vial thymidine kinase in infected cells and then activated to a triphosphate form by host cellular kinases in order to be inserted into newly synthesizing DNA?
what drug can be used for CMV in immunocompromized pts?
ganiciclovir or it's prodrug (valganiciclovir) which has better bioavailability
what are the major side effects of the guanisine analgogues (e.g. acyclovir)?
obstructive crystalline nephropathy and acute renal failure
what can be used to prevent renal toxicitiy from acyclovir?
what is the major side effect of ganciclovir?
bone marrow suppression and renal toxicity
What is the mechanisms of resistance to acyclivir?
mutated viral thymidine kinase
what is the mechanism of action of foscarnet?
FOScarnet inhibits viral DNA/RNA polimerase and also inhibits HIV reverse transcriptase by competing for pyroFOSphate binding site
used for acyclovir-resistant HSV
what is hte mechanism of resistance for foscarnet?
FOScarnet work by allosterically inhibiting viral polymerases (binds to pyroFOSphate binding site), so virsuses with mutated DNA polymerases can be resistant
What are the main side effects of foscarnet?
nephrotoxicity, electrolite imbalances, SEIZURES!
What antiviral drug preferentially inhibits viral DNA polimerase, does not require phosphorilation by viral kinase, causes nephrotoxicity and is not foscarnet?
what should be given with cidofovir/tenovir to prevent toxicity?
probenecid + IV saline
*probenecid inhibits organic anion transport in the renal proximal tubule