Anti-Virals

Question 1

Zanamivir, Oseltamivir: mech

Answer 1

Inhibit influenza neuraminidase –> decrease release of progeny of virus

Question 2

Zanamivir, Oseltamivir: use

Answer 2

Tx and Px of both influenza A and B

Question 3

Ribavirin: mech

Answer 3

Inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase

Question 4

Ribavirin: use

Answer 4

RSV, chronic hep C

Question 5

Ribavirin: tox

Answer 5

Hemolytic anemia. SEVERE teratogen

Question 6

Acyclovir, famciclovir, valacyclovir: mech

Answer 6

Monophosphorylated by HSV/VZV thymidine kinase and not phosphorylated in uninfected cells –> few adverse effects. GUANOSINE ANALOG. Triphosphate formed by cellular enzymes.
Preferentially inhibits viral DNA polymerase by chain termination.

Question 7

Acyclovir, famciclovir, valacyclovir: use

Answer 7

HSV and VZV. Weak activity against EBV. No activity against CMV. Used for HSV-induced mucocutaneous and genital lesions as well as for encephalitis. Px in immunocompromised pts. No effect on latent forms of HSV and VZV.
Valacyclovir, a prodrug of acyclovir, has BETTER ORAL bioavailability. (use during prodrome may prevent symptoms)

Question 8

Acyclovir, famciclovir, valacyclovir: tox

Answer 8

Obstructive crystalline nephropathy and acute renal failure if not adequately hydrated.

Question 9

Acyclovir, famciclovir, valacyclovir: MOR

Answer 9

Mutated viral thymidine kinase

Question 10

Ganciclovir: mech

Answer 10

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

Question 11

Ganciclovir: use

Answer 11

CMV, esp in immunocompromised pts. Valganciclovir, a prodrug of ganciclovir, has BETTER ORAL bioavailability

Question 12

Ganciclovir: MOR

Answer 12

Mutated CMV DNA polymerase or lack of viral kinase.

Question 13

Foscarnet: mech

Answer 13

Viral DNA polymerase inhibitor that binds to the pyrophosphate-binding site of the enzyme. Does not require activation of viral kinase.
FOScarnet = pyroFOSphate analog

Question 14

Foscarnet: use

Answer 14

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

Question 15

Foscarnet: tox

Answer 15

Nephrotoxicity

Question 16

Foscarnet: MOR

Answer 16

Mutated DNA polymerase

Question 17

Ganciclovir: tox

Answer 17

Leukopenia, neutropenia, thrombocytopenia, renal tox. More toxic to host enzymes than acyclovir. Teratogen

Question 18

Cidofovir: mech

Answer 18

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

Question 19

Cidofovir: use

Answer 19

CMV retinitis in immunocompromised pts; acyclovir-resistant HSV. Long half-life.

Question 20

Cidofovir: tox

Answer 20

Nephrotoxicity (coadminister with probenecid and IV saline to decrease toxicity)

Question 21

Interferons: mech

Answer 21

Glycoproteins normally synthesized by virus-infected cells, exhibitng a wide range of antiviral and antitumoral properties

Question 22

IFN-alpha: use

Answer 22

chronic hep B and C, Kaposi sarcoma, hairy cell leukemia, condyloma acuminatum, renal cell carcinoma, malignant melanoma

Question 23

IFN-beta: use

Answer 23

MS

Question 24

IFN-gamma: use

Answer 24

CGD

Question 25

IFN tox

Answer 25

neutropenia, myopathy