Anti Viral 2

Question 1

What is the mechanism of action for Foscarnet?

Answer 1

Viral DNA/RNA polymerase inhibitor and HIV reverse transcriptase inhibitor. Binds to the pyrophosphate-binding site of the enzyme. Does not require any kinase activation. Foscarnet = pyrophosphate analog.

Question 2

What is the clinical use of Foscarnet?

Answer 2

CMV retinitis in immunocompromised patients when ganciclovir fails; acyclovir-resistant HSV.

Question 3

What are the adverse effects of Foscarnet?

Answer 3

Nephrotoxicity, multiple electrolyte abnormalities, which can lead to seizures.

Question 4

What is the mechanism of resistance for Foscarnet?

Answer 4

Mutated DNA polymerase.

Question 5

What is the mechanism of action for Cidofovir?

Answer 5

Preferentially inhibits viral DNA polymerase. Does not require phosphorylation by viral kinase.

Question 6

What is the clinical use of Cidofovir?

Answer 6

CMV retinitis in immunocompromised patients. Long half-life.

Question 7

What are the adverse effects of Cidofovir?

Answer 7

Nephrotoxicity (coadminister cidofovir with probenecid and IV saline to reduce toxicity).

Question 8

What is the mechanism of resistance for Cidofovir?

Answer 8

Mutations in the viral DNA polymerase gene.