Respiratory Antivirals

Question 1

what virus most affects children causing community acquired pneumonia

Answer 1

• RSV

Question 2

what virus most affects adults, the elderly, and immunocompromised which causes community acquired pneumonia

Answer 2

• influenza A/B

Question 3

is CMV a DNA or RNA virus

Answer 3

• DNA virus

Question 4

what kind of viruses are flu and RSV?

Answer 4

• (-)ssRNA

Question 5

how do you treat CMV

with what drugs?

Answer 5

• block viral DNA synthesis

- ganciclovir/valgancycloir

Question 6

MOA of Ganciclovir

Answer 6

• mimics nucleotide guanosine during viral DNA replication
• converted into triphosphate by viral and cellular enzymes
• competes with GTP for binding to polymerase
• incorporates into DNA causing chain termination

Question 7

what enzyme converts gancyclovir into its active form

and how?

Answer 7

• CMV kinase (a viral enzyme)

- phosphorylates

Question 8

resistance to ganciclovir

Answer 8

• mutations in viral proteins CMV kinase and CMV DNA polymerase

Question 9

toxicities of ganciclovir

Answer 9

• myelosuppression
• thrombocytopenia
• neutropenia

Question 10

can you use ganciclovir and valganciclovir in pregnancy

Answer 10

• potential teratogen and embryotoxin

Question 11

pharmacokinetic issues with ganciclovir

Answer 11

• low oral bioavailability

- so you give it in pro-drug valgancyclovir first

Question 12

which influenza coat proteins are drug targets

Answer 12

• neuraminidase

- M2 ion channel

Question 13

MOA of amantadine and rimantadine

Answer 13

• inhibit viral uncoating of flu virus by blocking M2 proton pump

Question 14

how M2 proton pump works

Answer 14

• acidifies interior of virion which facilitates uncoating of flu virus

Question 15

MOA of oseltamivir and zanamivir

Answer 15

• prevent cleavage of sialic acid-hemagglutinin complex,

- virus cannot be released

Question 16

oseltamivir results

Answer 16

• marginal, but significant therapeutic effects

Question 17

how do you take zanamivir

Answer 17

• inhaled

Question 18

toxicities of zanamivir

avoid use in patients with

Answer 18

• bronchospasm

- asthma or COPD

Question 19

can you give oseltamivir and zanamivir during pregnancy

Answer 19

• good for pregnancy

Question 20

MOA of ribavirin

Answer 20

• guanosine analog
• inhibits GTP synthesis
• inhibits RNA replication
• incorporates into RNA producing a defective genome

Question 21

pharmacokinetic issues with ribavirin

Answer 21

• has high volume of distribution
• concentrates in RBCs
• can cause hemolytic anemia

Question 22

do we use ribavirin during pregnancy

Answer 22

• ABSOLUTELY NOT
• potential DNA damage
• teratogenic, embryo toxic

Question 23

if a women is given ribavirin, what should happen next

Answer 23

• birth control for 7 months

Question 24

drug interactions with ribavirin

problem with this

Answer 24

• blocks activation of HIV reverse transcriptase inhibitors (AZT)
• HIV+ patients are immunocompromised and more likely to get RSV and now they can’t be treated for it