Antivirals

Question 1

anti-herpes drugs (acyclovir) mechanism of action

Answer 1

*acyclic guanosine analogues with high affinity for phosphorylation by VIRAL thymidine kinase
*once triphosphorylated, it prevents viral replication by inhibiting DNA polymerase

Question 2

acyclovir spectrum

Answer 2

active against HSV-1, HSV-2, and VZV

Question 3

acyclovir - mechanism of resistance

Answer 3

MUTATION in viral thymidine kinase (or TK deficiency)

Question 4

valacyclovir benefits and indications

Answer 4

*better intracellular concentration and bioavailability (prodrug esters)
*works better against VZV than acyclovir

Question 5

ganciclovir - overview

Answer 5

*mechanism of action and resistance similar to that of acyclovir
*more active against CMV!

Question 6

ganciclovir indications

Answer 6

CMV infections in immunocompromised people and/or severe CMV infections
*IV only (valganciclovir is oral form)

Question 7

ganciclovir toxicity

Answer 7

**bone marrow suppression (myelosuppression)

Question 8

foscarnet - mechanism of action

Answer 8

*DIRECTLY inhibits DNA polymerase of human herpesviruses

Question 9

foscarnet - indications

Answer 9

used for resistant herpesviruses (HSV, VZV, and CMV)

Question 10

foscarnet - toxicities

Answer 10

*nephrotoxicity
*electrolyte disturbances

Question 11

cidofovir - overview

Answer 11

novel nucleotide analog
*uses CELLULAR (host) thymidine kinases to produce the diphosphate form

Question 12

M2 protein inhibitors

Answer 12

*amantadine and rimantadine
*used for influenza A only

Question 13

neuraminidase inhibitors

Answer 13

*oseltamivir and zanamivir
*active against influenza A and B

Question 14

when are the neuraminidase inhibitors helpful against influenza

Answer 14

*when started within 48 hours of symptom onset
*can also be used for influenza prophylaxis

Question 15

NA inhibitors (oseltamivir) - toxicities

Answer 15

nausea and vomiting

Question 16

ribavirin - mechanism of action

Answer 16

phosphorylated metabolites inhibit viral nucleaic acid synthesis

Question 17

ribavirin - uses

Answer 17

RSV, hantavirus

Question 18

ribavirin - toxicity

Answer 18

teratogenic

Question 19

drugs for treatment of Hep B

Answer 19

all nucleoside analogues:
*lamiviudine (also for HIV)
*adefovir
*tenofovir (also for HIV)
telbivudine
**entecavir - best if not HIV+

Question 20

treatments for hep C

Answer 20

direct acting antiviral drugs (replication inhibitors and protease inhibitors)
*can CURE hep C

Question 21

remdesiver - mechanism of action & indication

Answer 21

*COVID-19 in hospitalized pts (IV only)
*MOA: inhibits viral RNA-dependent RNA polymerase

Question 22

paxlovid - mechanism of action and indications

Answer 22

*COVID-19 (outpatient; oral)
*MOA: inhibits viral protease MPRO