ALS 6 Flashcards
virus
obligate intracellular parasite
genome made of DNA and RNA
prophylaxis
preventing the disease before the etiologic agent is acquired by vaccination or by giving drug before the infection
therapy
treatment of the disease when the host is infected by the virus
analogue substrate definition
substrate of the enzyme with chemical modifications that does not allows dissociation of the substrate to the enzyme
the substrate is locked into the active site
substrate analogue uses
prevent virus DNA replication by blocking the chain addition of DNA or RNA synthesis
acyclovir
chain terminator that locks -OH group, no phosphodiester bonds are formed
why acyclovir not kill us?
activated only inside virus infected cells
ACV to ACVMP by phosphorylation
ACVMP to ACVTP by cellular enzymes
ACVTP has higher affinity to viral DNA polymerase than host
characteristics of a drug
effective and specific to the target viral function
easy to administer
effective against most variants of the influenza virus
few sides effects
classes of drugs used against influenza
prevent virus out of endosome
target RNA dependent viral polymerase
target neuraminidase for viral particles release
amantidine
sits in the M2 protein ion channels that protonates the virus and prevent proton entry
amantidine resistance
single point mutation in the M2 protein (S3IN)
drug does not bind anymore
low cost to fitness of the virus
H3N2
circulating virus resistant to amantidine
H5N1
resistant due to poultry overuse
pH1N1
swine flu emerged carrying S3IN
baloxivir
inhibits polymerase acidic endonuclease
baloxivir resistance
single point mutation in the PAI38T common in H3N2 virus
relenza
higher avidity for enzyme, goes in but cannot come out therefore the enzyme cannot turnover
tamiflu
same effect as relenza but available orally
neurominidase function
cleaves viral molecules made by infected cells to be released into the circulation
neurominidase inhibitor
prevent cleavage of the viral molecules into the circulation, being therefore tethered into the cell host resulting in no spread or replication
effects of HIV anti-virals
fusion inhibitors with the cell membrane
reverse transcriptase inhibitor
combination therapy
use of multiple drugs at the same time to combat mutation of a single gene that confers resistance