Anti-viral agents 1 and 2 Flashcards
Give 2 examples of DNA viruses:
Herpes
Chickenpox
Give an example of a retrovirus:
HIV
Give 2 examples of RNA viruses:
influenza
ebola
Give an example of a virus which is DNA but with a retroviral phase:
HepB
Polio is a positive sense virus, what does this mean?
its RNA is the same as the mRNA so doesn’t have to go through an extra step
What is a negative sense virus?
where the RNA has to be copied to give the positive sense mRNA
What are the two main drugs to treat influenza?
Oseltamivir
Zanamivir
these are neuraminidase inhibitors (TS inhibitors)
What is the function of neuraminidase?
to cleave the sugar unit of sialic acid which is essential in the mucus lining of URT
How is zanamivir administered compared to oseltamivir?
zanamivir: inhalation (poor bioavailability)
oseltamivir: oral (pro-drug)
What causes the common cold?
human rhinoviruses (positive sense RNA virus)
What is idoxuridine used for?
HSV
toxic for internal use, therefore topical for eye infections and cold sores
How does acyclovir work?
it is a selective inhibitor of HSV DNA polymerase, leading to termination of a growing DNA strand (missing ‘3OH group)
targets thymidine kinase
If acyclovir targets thymidine kinase, how come it doesn’t target human cells?
as acyclovir has a much lower affinity to human cells compared to viral cells
What are side effects of acyclovir (esp. if injected)?
nausea, diarrhoea, headache, tremors, delirium
minimised if topical use (poorly absorbed therefore not not for oral use)
what is ganciclovir?
more toxic than acyclovir
used for cytomegalovirus (like HSV viruses)
