Antivirals Flashcards
Tx of respiratory viral infections
neuraminidase inhibitors
inhibitors of viral uncoating
synthetic guanosine analog
oseltamivir
neuraminidase inhib
zanamivir
neuraminidase inhib
amantadine
inhibts viral uncoating
rimantadine
inhibitors of viral uncoating
ribavirin
synthetic guanosine analog
neuraminidase inhibitors
oseltamivir, zanamivir
work against type A and B influenza - prophylaxis OR after onset of sxs
neuraminidase inhib MOA
neuraminidase cleaves hemaglutinin residues from surface receptors - allows cleavage and budding of virus
–> INHIBITION of virion release d/t halted viral replication
olsetamivir vs zanamivir
olsetamivir: ORAL - hydrolyzed in liver
zanamivir: INHALE or INTRANASAL - less bioavail`
zanamivir AE
airway irritation - avoid in pt with asthma and COPD
Ion channel blockers
amantadine, rimantadine
only active on influenza type A
- not recommended as first line tx anymore b/c resistance
ion channel blocker MOA
blocks viral membrane protein - M2 (H+ channel)
- channel needed for fusion of viral with cell membrane to endosome
amantadine vs rimantadatine? which crosses BBB
amantadine = crosses BBB
- excreted in urine
greater AE with amantadine
ion channel blockers contraindications
pregnancy
nursing
ribavarin use
active against RNA/DNA viruses - broad spec
used in combo with IFN-alpha or HCV tx
ribavarin MOA
convert to ribavirin - triphosphate = inhibits GTP formation - no viral mRNA capping
inhib RNA dep RNA polym = inhib of protein synthesiss
ribavarin AE
dose dependent transient anemia
GI
CNS
PREGNANCY X - teratogen, can also affect those nearby, doesn’t need to be ingested by only 1 person
hepatic viral infection tx
1) IFN-alpha
2) nucleotide analog
3) protease inhibitors
ifn alpha
glycoproteins/cytokines - alpha and beta produced by many cell types
IFN-a MOA
naturally occuring
an be peglyated
nucleoside analogs
lamiduvidne
entecavir
lamidvudine
protect against hep B and HIV - in triphosphate form
monophosph form = incorporated into DNA (via HBV polymerase) – chain termination
entecarvir use
effective against lamivudine resistant HBV and HIV strains
phosphorylated form = competes for viral polymerase - inhibitiors blocks reverse transcriptase
STOPS ASSEMBLY and maturation