Anti-Herpes

Question 1

Acyclovir

Answer 1

Characteristics:
- 200x more selective for HSV TK than Mammalian TK
- Phosphorylated 3x

MOA:
- Competitive inhibition of viral DNA polymerase
- Incorporated into DNA primer strand
–> Virus can not replicate properly

Indication:
- Treats HSV
- Treats VZV
- Ineffective against CMV

Question 2

Penciclovir

Answer 2

Prodrug: Famciclovir

Characteristics:
- Is used in place of Acyclovir
- Treats HSV 1 and 2
- Treats VZV
- Ineffective against CMV
- Has to be Phosphorylated 3x

MOA:
- Competitive inhibition of viral DNA polymerase
- Incorporated into DNA primer strand
–> Virus can not replicate properly

Question 3

Ganciclovir

Answer 3

Characteristics:
- Phosphorylate by Thymidine Kinase (HSV)
- Phosphorylate by Phosphotransferase/Phosphokinase (CMV)
- Has to be Phosphorylated 3x

MOA:
- Competitive inhibition of viral DNA polymerase
- Incorporated into DNA primer strand
–> Virus can not replicate properly

Indication:
- Treats HSV 1 and 2
- Treats VZV
- Very Effective against CMV

Question 4

Cidofovir

Answer 4

Characteristics:
- Has to be Phosphorylated 2x
- Metabolized by Cellular Kinase instead of Thymidine Kinase

MOA:
- Competitive inhibition of viral DNA polymerase
- Incorporated into DNA primer strand
–> Virus can not replicate properly

Indication:
- Treats HSV 1 and 2
- Treats VZV
- Treats against CMV

Question 5

Foscarnet

Answer 5

Characteristics:
- Treats HSV, VZV, CMV
- Works well against viruses with deficient TK
–> Good for ganciclovir-resistant CMV
–> Good for acyclovir-resistant HSV/VZV
- Does not require phosphorylation

MOA:
Blocks cleavage of PPi from dNTPs
- Inhibits Viral DNA Polymerase

Question 6

Idoxuridine

Answer 6

Characteristics
- Cellular Kinase
- 3x Phosphorylation
- Targets HSV-1 and 2
- Used Topically

Question 7

Trifluridine

Answer 7

Characteristics:
- Cellular Kinase
- Treats HSV 1 and 2
- Has to be used topically

MOA:
- Monophosphate inhibits thymidylate synthase
–> Inhibiting DNA synthesis
- Triphosphate inhibits vDNA polymerase

Question 8

Vidarabine

Answer 8

Characteristics:
- Purine Nucleoside Analog
- Cellular Kinase
- Targets HSV 1,2 VZV, EBV
MOA:
- Inhibits vDNA Polymerase

Question 9

Docosanol

Answer 9

Characteristics:
- Treats HSV

MOA:
- Inhibit Viral Entry into Cell

Question 10

Fomivirsen

Answer 10

Characteristics:
- Treats CMV

MOA:
- Blocks translation of viral mRNA
- Inhibits virus binding to cells