Antivirals Flashcards
What is rimantadine used to treat?
influenza A
What is the mechanism of action of rimantadine?
it blocks the M2 proton channel and prevents viral uncoating
How and when is rimantadine given?
orally within the first 48 hours of exposure
What is oseltamivir used to treat?
influenza
Oseltamivir is also known as what?
tamiflu
What is the mechanism of action of oseltamivir?
it blocks neuraminidase
What is special about the pharmacokinetics of oseltamivir?
it is given as a prodrug that must be activated in the gut and liver
What is zanamivir used to treat?
influenza A and B
What is the mechanism of action of zanamivir?
it blocks neuraminidase
How and when is zanamivir administered?
oral inhalation within the first two days of infection
What is the major adverse effect associated with zanamivir?
it may cause bronchospasm in asthmatics
List the three important anti-influenza medications.
- rimantidine
- oseltamivir
- zanamivir
What is the mechanism of action of ribavirin?
it is an anti-metabolite that blocks GTP formation, inhibits viral mRNA capping, and inhibits viral RNA-dependent polymerase
What is responsible for the selectivity of ribavirin?
- it has no kinase selectivity
- it has a selectivity for viral polymerase
What are the indications for ribavirin?
- orally and with INFa for HepC
- as an aerosol for respiratory syncytial virus
What are the adverse effects of ribavirin?
- known teratogen and embryotoxin
- may cause a dose-dependent anemia
What is the mechanism of action of acyclovir?
it is a guanosine analog and chain terminator which inhibits viral genome replication
What is responsible for the selectivity of acyclovir?
viral kinase and polymerase specificity
Which viruses are resistant to acyclovir?
those that are without thymidine kinase
What is acyclovir used to treat?
HSV-1 and HSV-2
What is the mechanism of action of ganciclovir?
it is a guanosine analog anti-metabolite which inhibits viral genome replication
How does the selectivity of ganciclovir compare to that of acyclovir?
it is less kinase and polymerase specific than acyclovir
What is ganciclovir used to treat?
retinitis and visceral effects of CMV
What are the side effects of ganciclovir?
due to reduced selectivity compared to acyclovir
- teratogenic
- myelosuppressive
- neuropathic
How well tolerated is acyclovir?
very well given its high selectivity
What is the mechanism of action of foscarnet?
it is a pyrophosphate anti-metabolite which directly inhibits viral polymerase to prevent viral genome replication
What is foscarnet used to treat?
- synergistic with ganciclovir for CMV
- used for valcyclovir-resistant herpes simplex
What is the primary adverse effect of foscarnet and how do we deal with it?
it is potentially nephrotoxic, so use a saline preload
What is the mechanism of action of cidofovir?
it is a cytosine anti-metabolite
Describe the selectivity of cidofovir?
it has no kinase specificity, just polymerase specificity
What is cidofovir used to treat?
herpes simplex and CMV
How is cidofovir cleared from the body?
active tubular secretion
Cidofovir is usually given alongside what other drug?
probenecid to increase bioavailability
Cidofovir has what adverse effect?
dose-dependent nephrotoxicity
What is the mechanism of action of trifluridine.
it competes with TTP for viral polymerase
Describe the selectivity of trifluridine.
it has very low specificity, activated by hosts kinases and low polymerase specificity
How is trifluridine used?
- limited selectivity restricts it to topical use
- best for HSV conjunctivitis or epithelial keratitis
List five drugs used to treat herpes by inhibiting viral genome replication.
- acyclovir
- ganciclovir
- foscarnet
- cidofovir
- trifluridine
List five drugs used to treat hepatitis.
- interferon alpha
- lamivudine
- telaprevir
- simeprevir
- sofosbuvir