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Flashcards in Topical Antivirals Deck (18)
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1
Q

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

A

T

2
Q

Cidofovir depends on viral TK for phosphorylation

A

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

3
Q

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

A

True

4
Q

Imiquimod Is a non nucleoside heterocyclic amine

A

T

5
Q

Imiquimod activates toll like receptor 5

A

False

TLR7

6
Q

Bleomycin acts during M and G2 phases of cell cycle causing single strand DNA breakage

A

T

7
Q

Podophyllotoxin is active ingredient in podophyllin and podofilox

A

T

8
Q

Podophyllotoxin is an antimitotic agent that arrests cells in metaphase

A

T

9
Q

Podophyllotoxin binds irreversibly to tubulin

A

False

Reversibly

10
Q

Podophyllotoxin is contraindicated in pregnancy

A

T

11
Q

Trichloroacetic acid can be used in pregnant for cervical warts

A

T

12
Q

Acyclovir is specific for HSV infected cells as drug requires phosphorylation by viral enzyme thymidine kinase

A

True

13
Q

Pencyclovir is an acyclic purine nucleoside analog of guanine

A

T

14
Q

Acyclovir MoA

A

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
15
Q

What is cidofovir active metabolite ?

A

It is to be phosphorylated to Cidofovir diphosphate

16
Q

Cidofovir competitively inhibits deoxycytosine triphosphate

Not phosphorylated by viral TK

A

T

17
Q

Foscarnet is. Pyrophosphate analog

A

T

18
Q

Pyrophosphate interferes with cleavage of pyrophosphate from deoxyguanosine triphosphate

A

False

Deoxyadenosine