Topical Antivirals Flashcards
Pencyclovir exhibits more efficient phosphorylation and higher affinity of viral DNA polymerases for its triphosphate form
&
Increased stability of the triphosphate form leading to longer duration of activity
Cf. acyclovir
T
Cidofovir depends on viral TK for phosphorylation
False
Cidofovir requires two stages of phosphorylation to form the active metabolite Cidofovir diphosphate
–> competitive inhibitor of deoxycytosine-59-triphosphate for incorporation into viral DNA by viral DNA polymerases . After incorporation , blocks further viral DNA synthesis
Cidofovir requires two stages of phosphorylation to form the active metabolite Cidofovir diphosphate
–> competitive inhibitor of deoxycytosine-59-triphosphate for incorporation into viral DNA by viral DNA polymerases
True
Imiquimod Is a non nucleoside heterocyclic amine
T
Imiquimod activates toll like receptor 5
False
TLR7
Bleomycin acts during M and G2 phases of cell cycle causing single strand DNA breakage
T
Podophyllotoxin is active ingredient in podophyllin and podofilox
T
Podophyllotoxin is an antimitotic agent that arrests cells in metaphase
T
Podophyllotoxin binds irreversibly to tubulin
False
Reversibly
Podophyllotoxin is contraindicated in pregnancy
T
Trichloroacetic acid can be used in pregnant for cervical warts
T
Acyclovir is specific for HSV infected cells as drug requires phosphorylation by viral enzyme thymidine kinase
True
Pencyclovir is an acyclic purine nucleoside analog of guanine
T
Acyclovir MoA
Acyclovir is phosphorylated by viral thymidine kinase to acyclovir monophosphate which is then further metabolized to acyclovir triphosphate by HUMAN CELLULAR GUANYLATE KINASE
- -> acyclovir triphosphate inhibits viral DNA polymerase
- -> acyclovir triphosphate is mistaken for deoxyguanosine triphosphate and becomes irreversibly incorporated into viral DNA
What is cidofovir active metabolite ?
It is to be phosphorylated to Cidofovir diphosphate
