Antivirals (non HIV/Hep) Flashcards
Herpes simplex virus (HSV) (profile)
2 most common types:
1st is oral
2nd is genital
man is only natural host
Herpes simplex virus (HSV) that is fatal?
Neonatal HSV (transmission from mother to child) rare but commonly FATAL to the child (25% of time)
Acyclovir (MOA)
irreversible binding to elongating viral DNA, preventing republication from occurring
unique analog b/c it is IRREVERSIBLE
what must nucleoside anti-viral drugs be transformed into for activity?
Nucleotide triphosphates
3 P groups
Virus Kinases cause what kind of phosphorylation?
MONO-phosphorylation
Virus Kinases (profile)
viruses have an enzyme that activates the antiviral drug, by adding a P group (the host cells add the other 2 P groups)
this means that the drug will not become active in cells that are not infected
which virus uses Thymidine kinase?
Herpes simplex virus (HSV) Varicella Zoster (VZV)
which virus uses UL97 kinase?
Cytomegalovirus (CMV) only
Virus to Drug?
HSV (herpes)
VZV (varicella)
CMV
HSV = ACV VZV = PCV CMV = GCV
Who adds the other 2 P groups to antiviral drug?
Host cells (Cell kinases)
Antiviral agents (non-retrovirals) (MOA)
inhibit viral DNA polymerase
which nucleoside is Acyclovir similar to?
Guanosine
only difference is that Acyclovir does not contain a hydroxyl (OH) group
Acyclovir (profile)
close to perfect antiviral drug
highly effective, highly selective against HSV
prodrug (means it needs to be activated)
activation requires 3 P groups
Nucleoside Esters are prodrugs with ____ oral bioavilability
Higher
Valacyclovir with De-acylation is ____?
Acyclovir
Famciclovir with De-acetylation is ____ ?
Penciclovir
Penciclovir vs Acyclovir
PCV is less active than ACV but has a longer half life (less frequency of administration required)
Acyclovir (Adverse effects)
Well tolerated by most
Pregnancy cat B
if patient is dehydrated, crystal formation can occur (acute renal failure)
Ganciclovir (profile)
active against CMV
CMV typically just develops in imunosupressed patients (cancer or transplants)
Ganciclovir (Adverse effects)
associated with bone marrow suppression
monitor for hematologic and renal toxicity (especially with patients taking cyclosporine)
Pregnancy cat C
how is Cidofovir activated?
host cell kinases convert to nucleotide triphosphate
no viral mediated phosphorylation
Cidofovir (MOA)
inhibits viral DNA polymerase
used for ophthalmic infections in immunocompromised patients
used for CMV
Cidofovir (adverse effects)
Systemic toxicity
Nephrotoxicity (do not use with NSAIDS)
how do you lessen nephrotoxicity caused by Cidofovir?
administer with probenecid (blocks tubular secretions)