Antiviral therapy

Question 1

Block M2 channel, only effective against Influenza A

Answer 1

Adamantanes

Release of the viral ribonucleoprotein depends on acidification of the endosome. As the pH of the endosome drops, an ion channel, M2, in the viral membrane allows H+ into the virus.

Recal Hemaglutanin binds to sialyc acid

Question 2

Inhibit Influenza Neuraminidase

Answer 2

Zanamivir, Osltamivir

Treats Influenza A and B

Question 3

Inhibits synthesis of guanine nucleotides by competitively inhibiting IMP dehydrogenase

Answer 3

Ribavirin

inosine 5’-phosphate + NAD+ + H2O –> xanthosine 5’-phosphate + NADH + H+

RSV, chronic Hep C

Question 4

Hemolytic Anemia S/E

Answer 4

Ribavirin

Question 5

Teratogen, Severe

Answer 5

Ribavirin

Question 6

Monophosphorylated by HSV/VZV thymidine kinase. Guanosine analog. Triphosphate formed by cellular enzymes. Preferentially inhibits viral DNA polymerase by chain termination.

Answer 6

Acyclovir

HSV and VZV (no effect on latent forms)

Weak activity against EBV

NO activity against CMV

Question 7

Valcyclovir, a prodrug of acyclocir, has ___________

Answer 7

better oral bioavailability

Question 8

For herpes zoster, use ___________

Answer 8

Famciclovir

Question 9

Mechanism of resistance of acyclovir

Answer 9

Mutated thymidine kinase

Question 10

5’-monophosphate formed by a CMV viral kinase. Guanosine analog. Triphosphate formed by cellular kinases. Preferentially inhibits viral DNA polymerase

Answer 10

Gancyclovir

CMV, especially in immunocompromised

Question 11

Valganciclovir, a prodrog of gancyclovir, has ____________

Answer 11

better oral bioavailability

Question 12

S/E Leukopenia, Neutropenia, Thrombocytopenia, Renal Toxicity

Answer 12

Ganciclovir

More toxic to host enzymes than acyclovir

Question 13

Mechanism of resistance of gancyclovir

Answer 13

Mutated CMV DNA polymerase or lack of viral kinase

Question 14

Viral DNA polymerase inhibitor that binds to the pyrophosphate-binding site of the enzyme

Does not require activation by viral kinase

Answer 14

Foscarnet (pyroPHOsphate analog)

CMV retinitis in immunocompromised when gancyclovir fails or acyclovir-resistance HSV

Question 15

S/E Nephrotoxic

Answer 15

Foscarnet

Question 16

Mechanism of resistance of Foscarnet

Answer 16

Mutated DNA polymerase

Question 17

Preferentially inhibits viral DNA polymerase.

Does not require phosphorylation by viral kinase.

Answer 17

Cidofovir

CMV retinitis in immunocompromised, acyclovir-resistant HSV

Long half life

Question 18

Nephrotoxicity - coadminister with probenecid and IV saline to reduce it

Answer 18

Cidofovir

Question 19

IFN-alpha

Answer 19

Hep B, C

Question 20

IFN - Beta

Answer 20

MS

Question 21

IFN-Gamma

Answer 21

NADPH oxidase deficiency

Question 22

S/E Neutropenia, Myopathy

Answer 22

Interferons