Antivirals Flashcards
HSV/ VZV- correspond to what HHVs
1,2,3
First line Tx for HSV, VZV
Acylovir, Valacyclovir, Penciclovir, Famicilovir
Alternative Tx for HSV and VZV
Cidofovir, Foscarnet, Vidarabine
Acyclovir- Drug class
Nucleoside analog of Guanosine
Acyclovir- MOA
viral thymidine kinase converts Acyclovir to acylco GMP –> inhibits viral DNA pol, chain termination
Acyclovir- admin
Topical, IV, Oral- not absorbed well orally
Acyclovir- elimination
renal
Acyclovir MOR
viral TK or viral DNA polymerase mutation
Acyclovir t1/2
3 hr
Acyclovir AE
Acyclovir has poor solubility, ensure adequate hydration to prevent crystalluria
Valcyclovir- Structure
Ester of Acyclovir
Valcyclovir advantages
Increased water solubility increases bioavailability
Pencicilovir Structure
Add OH group to Acyclovir
Penciclovir Advantage
increases intracellular concentration, prolonging the intracellular half life
Pencilovir Chain termination
Not an obligate chain terminator
Famciclovir Structure
Ester of Penciclovir
Famcilovir Advantage
More water soluble & Inc half life
Cidofovir structure
Nuleotide analog of Cytidine Monophosphate
Cidofovir activation
independent of the virus
Cidofovir MOA
viral DNA polymerase inhibitor –> chain termination
CIdofovir- Admin
IV
Cidofovir elim
Renal
Cidofovir- Uses
Resistant HHV1,2,3 and CMV (HHV5)
Cidofovir AE
dose limiting renal toxicity ensure is pre hydrated with IV saline
Cidofovir + Probenacid
Give probenacid to dec renal elimination of Cidofovir
Foscarnet Structure
Pyrophosphate analog
Foscarnet MOA
binds to pyrophosphate binding site of viral DNA pol –> inhibits it
Foscarnet Admin
IV
Foscarnet elim
Renal
Foscarnet AE
renal toxicity, prevent via hydration
Foscarnet resistance
mutation in viral DNA polymerase
Vidarabine Structure
Adenosine analog
Vidarabine MOA
viral TK coverts it to Ara- MP –> Ara- ATP inhibits viral DNA pol BUT NOT A CHAIN TERMINATOR
VIdarabine MOR
mutation in viral DNA pol
Vidarabine uses
Topical treatment for herpes keratitis. Limited systemic value b/c of metabolic inactivation and high toxicity
Tx for CMV
Cidofovir, Ganciclovir, Valganciclovir
Ganciclovir structure
similar to acyclovir but altered to be an inhibitor of UL97
Ganciclovir Admin
IV, not absorbed wel orally