Antivirals Flashcards
(24 cards)
What are the potential drug targets during viral replication?
- attachment of the viral particle to membrane
- penetration into the cytoplasm
- uncoating
- multiplication of genetic material
- protein synthesis
- assembly of new particle
- release
What is the most common veterinary use for antivirals?
ophthalmology to treat herpes in cats and horses
What is the most effective step of virus replication that an antiviral can inhibit?
viral attachment, as it stops the replication process before it has even started
How does amantadine work?
inhibits penetration and uncoating of influenza A virus
What is another use of amantadine?
analgesic, for animals that are unresponsive to others such as opiates
What antivirals target viral multiplication?
- idoxuridine
- acyclovir
- zidovudine/azidothymine
How does idoxuridine work?
- incorporated into viral DNA
- iodine prevents base pairing, so replication inhibited
Why is idoxuridine not given systemically?
because it also inhibits mammalian DNA replication
What is a veterinary use of idoxuridine?
herpetic keratitis in cats, topically given
How is acyclovir activated?
- phosphorylated 3 times
- first phosphorylation carried out by herpes thymidine kinase
- 2nd and 3rd carried out by host kinases
How does acyclovir work as an antivral?
inhibits DNA polymerase
What is acyclovir available as?
- ophthalmic ointment
- skin ointment
- tablet
- injection
What is acyclovir used for?
Herpes
What are the other forms of acyclovir?
gancyclovir and famcyclovir
What are the methods of acyclovir resistance?
- mutations in viral thymidine kinase, so acyclovir can’t be activated
- mutations in DNA polymerase
How does vidarabine work?
inhibits DNA polymerase, both host and viral, but more commonly viral
What is vidarabine used for?
topical eye treatment of herpes
How does zidovudine/azidothymidine work?
inhibits reverse transcriptase, also inhibits DNA polymerase at higher doses
How is zidovudine activated?
phosphorylated by host kinases
What is a veterinary use of zidovudine/azidothymidine?
treatment of FIV positive cats, can increase survival time and quality of life
What are the adverse effects of zidovudine/azidothymidine?
can cause hepatotoxicity and anaemia, so can’t be used in animals with renal or hepatic impairment
What is virbagen omega?
recombinant feline omega interferon
What is virabagen omega used for?
- parvovirus treatment
- treatment of FeLV and FIV
What is the mechanism of action of virabagen omega?
stimulate antiviral processes so the virus is destroyed and removed by the host
