AntiVirals

Question 1

Docosanol

“Abreva”

Answer 1

anti-herpes

22C long-chain alcohol - disturb cell membrane –> block virus entry (no fusion)

Question 2

Acyclovir

Answer 2

HSV - encephalitis (IV)
herpes (shingles) zoster
VZV

nucleoside analog (dGTP)
phosphorylated by thymidine Kinase to be active
(common resistance)

chain terminator (inhibit protein synthesis) - via 2 specificity:
herpes thymine kinase
herpes DNA polymerase

YES pregnant

renal damage if fast IV

Question 3

Val-acyclovir

Val-gancyclovir

Answer 3

valine added improves oral bioavailability

Question 4

Ganciclovir

Answer 4

nucleoside analog (dGTP) - similar to acyclovir

CMV
CMV retinitis - ophthalmic (pt CD4+

Question 5

fosCARnet

Answer 5

nucleoside analog (dGTP)
competitive inhibits pyrophosphate binding of viral DNA polymerase

CMV, CMV retinitis - IV
HSV 1, 2 - resistant to gan and acyclovir
HHV6
EBV

nephrotoxic - induce renal insufficiency
electrolyte disturbance (Ca, Mg, K low) -> seizures

Question 6

pritelivir

Answer 6

anti-HSV

helices-primase inhibitor –> block viral DNA replication (NO unwinding)

Question 7

direct-acting antivirals (DAAs)

HCV

Answer 7

inhibit viral protease (NS3)
viral phosphoprotein (NS5A)
viral polymerase (NS5B)

HCV genotype 1 (90% cure) - add ribavirin +IFN

peak [ ] in 4 days

Question 8

Ribarvirin

Answer 8

deplete GTP pool (guanine nucleotide analog)
directly block viral RNA polymerase -> inhibit viral replication
trigger antiviral T cell responses

HCV
RSV - aerosol

hemolytic anemia
teratogenic agent

Question 9

PegIFN

pegylated interferon

Answer 9

stimulates host antiviral immunity (INC gene expression)

HCV - genotypes 2, 3 (50% effective with ribavirin)
Chronic HBV

longer t1/2 of IFN bc of peg

Question 10

Entecavir

Answer 10

guanosine analog
inhibits HBV DNA priming, RT and DNA viral polymerase

chronic HBV (lamuvidine resistant)

lactic acidosis, rebound hep

Question 11

Tenofovir

Answer 11

prodrug hydrolyzes to adenosine analog –> phosphorylated to Ten-PPP –> blocks HBV DNA pol

chronic HBV
HIV inhibitor

renal toxicity
lactic acidosis

Question 12

Amantadine

Rimantadine

Answer 12

block vision M2 ion channel –> protons cannot enter virus –> virus RNA will not release from vision protein –> infection blocked at uncaring (disassembly) stage (prevent RNPs dissociating from virus entry site)

influenza A - but now resistant
S31N mutation in M2

Question 13

Oseltamivir - oral

Zanamivir - aerosol

Answer 13

neuraminidase inhibitors
cleaves silica acid from infected cells and virion –> inhibits/retards virus dissemination/release

influenza A and B
H274Y mutation in NA

resistance emerging - bc error prone RNA dependent RNA polymerase

Question 14

what step do both host and virus depend on?

Answer 14

Translation

virus uses host ribosome

Question 15

when to treat HBV?

Answer 15

liver failure, cirrhosis and HBV DNA+

OR

reactivation of chronic HBV after immunosuppression

Question 16

Palivizumab

Answer 16

passive immunotherapy for RSV