Antiviral agents

Question 1

Influenza virus

Answer 1

Enveloped RNA virus

Question 2

Treatment for influenza

Answer 2

Amantadine, zanamavir

Question 3

Amantadine MOA

Answer 3

Inhibits viral uncoating by inhibiting viral membrane protein M2

Question 4

Side effects of amantadine

Answer 4

CNS effects, primarily in elderly

Teratogenic, contraindicated in pregnancy

Question 5

Zanamavir MOA

Answer 5

Neuraminidase inhibitor. Prevents release of new virions and their spread from cell to cell

Question 6

Amantadine therapeutic use

Answer 6

Influenza A, resistance is common

Question 7

Zanamavir therapeutic use

Answer 7

Active against influenza A and B. Useful for pophylaxis and acute treatment. Decrease severity and duration of symptoms, if started within the first 48 hrs. Resistance is uncommon.

Question 8

Pharmacokinetics of Zanamavir

Answer 8

low oral bioavailability, available as a dry powder. May be a problem for those with respiratory illnesses

Question 9

Herpes virus

Answer 9

enveloped DNA virus. Herpes simplex I and II, Varicella zoster, cytomegalo virus

Question 10

Treatment for herpes virus

Answer 10

acyclovir and famciclovir

Question 11

Acyclovir and famciclovir MOA

Answer 11

phosphorylated by a viral thymidine-kinase, then metabolized by host cell kinases to nucleotide analogs which inhibit viral DNA polymerase. Incorporated into DNA, chain terminator.

Question 12

Therapeutic use of acyclovir and famciclovir

Answer 12

Resistance an increasing problem, especially the immunosupressed. Low oral bioavailability. Famciclovir is a more bioavailable variant

Question 13

Treatment of HSV keratitis

Answer 13

Trifluridine, only used topically. But acylovir has high penetrance and is effective. Frequently given together.

Question 14

Hepatitis C virus

Answer 14

enveloped RNA virus, number one reason for liver transplant

Question 15

Drugs to treat hepatitis C

Answer 15

Ribavirin, interferons

Question 16

MOA of ribavirin

Answer 16

guanosine analog that inhibits RNA pol

Question 17

Pharmacokinetics of ribavirin

Answer 17

widely distributed (except CNS), oral or IV,

Question 18

Adverse effects of ribavirin

Answer 18

anemia and jaundice

Question 19

Adverse effects of ribavirin and interferon

Answer 19

fatigue, cough, rash, pruritis, nausea

Question 20

Which interferon is therapy based on

Answer 20

alpha

Question 21

Antiviral mechanisms of interferon

Answer 21

inhibition of translation

Question 22

Pharmacokinetics of interferons

Answer 22

low oral bioavailability, distributed widely, half life 1-4 hrs. Pegylated interferon can be administered weekly