Antiviral 35-50

Question 1

Acyclovir (Zovirax, Stavig) mechanism

Answer 1

phosphorylated by Viral Thymidine kinase
Acyclovir Triphosphate accumulates in cell
Competes w/ dGTP, gets incorporated
Lack of 3’OH Inhibits Viral DNA polymerase (irreversible)

Question 2

Acyclovir spectrum

Answer 2

HSV1>HSV2>VZV

Question 3

Pencyclovir (Denavir) mechanism

Answer 3

Phosphorylated by Viral Thymidine kinase

Question 4

Acylcovir resistance

Answer 4

Mutant Viral thymidine kinase

Mutant viral DNA polymerase

Question 5

Famciclovir mechanism

Answer 5

Inactive prodrug converted to Pencyclovir

Question 6

Pencyclovir vs acyclovir

Answer 6

100 times less potent ant inhibition of DNA polymerase
Accumulates in higher conc.
Longer T1/2
Slows down polymerization rather than chain termination

Question 7

Gangciclovir (Cytovene) mechanism

Answer 7

Herpes: Viral thymidine kinase does first phosphorylation, then cellular kinaseses make di and triphosphates
CMV: UL97 Kinase phosphorylates the drug first

Question 8

Gangciclovir most effective against

Answer 8

CMV>HSV1>HSV2

Question 9

Gangcyclovir resistance

Answer 9

Mutation of viral DNA polymerase
CMV: UL97 mutation
Thymidine kinase mutation

Question 10

Ribavirin spectrum

Answer 10

Unusual broad spectrum: DNA and RNA

Categorized as RNA