Respiratory Antivirals Flashcards
what virus most affects children causing community acquired pneumonia
- RSV
what virus most affects adults, the elderly, and immunocompromised which causes community acquired pneumonia
- influenza A/B
is CMV a DNA or RNA virus
- DNA virus
what kind of viruses are flu and RSV?
- (-)ssRNA
how do you treat CMV
with what drugs?
- block viral DNA synthesis
- ganciclovir/valgancycloir
MOA of Ganciclovir
- 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
what enzyme converts gancyclovir into its active form
and how?
- CMV kinase (a viral enzyme)
- phosphorylates
resistance to ganciclovir
- mutations in viral proteins CMV kinase and CMV DNA polymerase
toxicities of ganciclovir
- myelosuppression
- thrombocytopenia
- neutropenia
can you use ganciclovir and valganciclovir in pregnancy
- potential teratogen and embryotoxin
pharmacokinetic issues with ganciclovir
- low oral bioavailability
- so you give it in pro-drug valgancyclovir first
which influenza coat proteins are drug targets
- neuraminidase
- M2 ion channel
MOA of amantadine and rimantadine
- inhibit viral uncoating of flu virus by blocking M2 proton pump
how M2 proton pump works
- acidifies interior of virion which facilitates uncoating of flu virus
MOA of oseltamivir and zanamivir
- prevent cleavage of sialic acid-hemagglutinin complex,
- virus cannot be released
oseltamivir results
- marginal, but significant therapeutic effects
how do you take zanamivir
- inhaled
toxicities of zanamivir
avoid use in patients with
- bronchospasm
- asthma or COPD
can you give oseltamivir and zanamivir during pregnancy
- good for pregnancy
MOA of ribavirin
- guanosine analog
- inhibits GTP synthesis
- inhibits RNA replication
- incorporates into RNA producing a defective genome
pharmacokinetic issues with ribavirin
- has high volume of distribution
- concentrates in RBCs
- can cause hemolytic anemia
do we use ribavirin during pregnancy
- ABSOLUTELY NOT
- potential DNA damage
- teratogenic, embryo toxic
if a women is given ribavirin, what should happen next
- birth control for 7 months
drug interactions with ribavirin
problem with this
- 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
