Antivirals

Question 1

Acyclovir (zovirax) MOA

Answer 1

Guanosine analogue.Inhibits DNA synthesis by competing with dGTP. Terminates the chain due to lack of 3 prime hydroxyl. Requires phosphorylation by viral thymidine kinase.

Question 2

Herpes DOC

Answer 2

Acyclovir

Question 3

Acyclovir resistance

Answer 3

decrease viral thymidine kinase so the drug can’t be activated by phosphorylation.

Question 4

Acyclovir kinetics

Answer 4

oral/IV/topical. Short half life. Concentrated (trapped) in viral cells. Excreted by the kidney

Question 5

Valcyclovir

Answer 5

pro-drug with higher bioavailability. Eventually converted into acyclovir.

Question 6

Acyclovir uses

Answer 6

genital herpes, oral herpes, herpes keratitis, encephalitis, prophylaxis in organ transplants.

Question 7

Acyclovir toxicity

Answer 7

nephrotoxicity with high IV doses (decreased with hydration), nausea/vomiting, HA. Safe to use during pregnancy.

Question 8

Docosanol (Abreva) MOA

Answer 8

Inhibits viral fusion

Question 9

Docosanol (abreva) uses

Answer 9

OTC topical preparation for cold sores

Question 10

Ganciclovir/valganciclovier MOA

Answer 10

Guanosine analogue activated by viral kinases. inhibits DNA polymerase. Less active and more toxic than Acyclovir.

Question 11

Ganciclovir kinetics

Answer 11

Ocular implant, IV, Oral.

Question 12

valganciclovir kinetics

Answer 12

Oral prodrug.

Question 13

Ganciclovir uses

Answer 13

CMV/Herpes in immunocompromised, CMV retinitis, Life threatening CMV infections.

Question 14

Ganciclovir toxicity

Answer 14

myelosuppression (neutro, thrombo, leuko) especially when used with zidovudine for HIV. Severe HA, confusion and seizures.

Question 15

Foscarnet (foscvir) MOA

Answer 15

directly inhibits DNA/RNA polymerase and reverse transcriptase. No need for phosphorylation (good for use in resistant strains).

Question 16

Foscarnet uses

Answer 16

Back up for HSV/CMV that are resistant to acyclovir or ganciclovir.

Question 17

Foscarnet toxicity

Answer 17

Renal, adjust the dose and hydration.

Question 18

Cidofovir (vistide) MOA

Answer 18

Cytosine analogue that inhibits viral DNA polymerase. Phosphorylated independent of viral enzymes.

Question 19

Cidofovir uses

Answer 19

Back up for resistant strains of CMV and HSV.

Question 20

Cidofovir toxicity

Answer 20

Dose dependent nephrotoxicity (hydration).

Question 21

Osteltamivir (tamiflu)/Zanamivier (Relenza) MOA

Answer 21

Neuraminidase inhibitor. Blocks the release of the virus from the host cell.

Question 22

Osteltamivir (tamiflu)/Zanamivier (Relenza) uses

Answer 22

Active against influenza A and B. Has to be used within 48 hours of symptom onset.

Question 23

Osteltamivir (tamiflu) administration

Answer 23

Oral. approved for >1 year of age. Also used for the bird flu.

Question 24

Osteltamivir (tamiflu) toxicity

Answer 24

nausea and vomiting (take with food)

Question 25

Zanamivier (Relenza) administration

Answer 25

nasal/oral inhaler. approved for >7 years of age.

Question 26

Zanamivier (Relenza) toxicity

Answer 26

Worsens COPD and asthma. Shouldn't be given if patient has any airway disease.

Question 27

Amantadine (symmetrel)/Rimantadine (flumadine) MOA

Answer 27

inhibits viral uncoating

Question 28

Amantadine (symmetrel)/Rimantadine (flumadine) uses

Answer 28

prophylactic or symptomatic treatment of influenza A. Rarely used due to rapid development of resistance.

Question 29

Ribavirin (virazole) MOA

Answer 29

Guanosine analogue that inhibits RNA polymerase and synthesis of GTP. Independent of viral kinases for phosphorylation.

Question 30

Ribavirin (virazole) toxicity

Answer 30

hemolytic anemia, respiratory depression, cardiac arrest, IV use cause psychiatric issues. TERATOGENIC! even with occupational exposure.

Question 31

RSV DOC

Answer 31

Ribavirin (virazole)

Question 32

Ribavirin (virazole) uses

Answer 32

DOC for RSV. Also used to treat HCV along with interferon.

Question 33

Interferon-alpha2b (intron-A) MOA

Answer 33

Blocks EVERYTHING (entry, transcription, translation, replication, processing, assembly and release). Given IV/IM.

Question 34

PEG-interferon

Answer 34

Interferon-alpha2b (intron-A) that is long lasting and given as a depot prep once a week.

Question 35

Interferon-alpha2b (intron-A) uses

Answer 35

HCV with ribavirin and chronic HBV.

Question 36

Interferon-alpha2b (intron-A) toxicity

Answer 36

Flu-like symptoms, CNS depression and suicide (MUST prescrive with an antidepressant), hematologic, cardiac (hypotension and edema).

Question 37

Boceprevir (victrelis) MOA

Answer 37

Blocks serine proteases needed for replication of HCV.

Question 38

Boceprevir (victrelis) uses

Answer 38

Oral. Can be added to interferon and ribavirin to treat HCV.

Question 39

Boceprevir (victrelis) toxicity

Answer 39

ihibitor of CYP3A4, exacerbates anemia, neutropenia and fatigue associated with interferon/ribavirin treatment.

Question 40

HBV DOC

Answer 40

Lamivudine.

Question 41

Lamivudine MOA

Answer 41

inhibits HBV polymerase (reverse transcriptase inhibitor)

Question 42

Lamivudine use

Answer 42

DOC for chronic HBV can also treat HIV. Oral. few side effects.

Question 43

Adefovir MOA

Answer 43

inhibits HBV DNA polymerase.

Question 44

Adefovir toxicity

Answer 44

renal toxicity

Question 45

Entecavir MOA

Answer 45

Guanosine analogue. Inhibits HBV DNA polymerase.