antivirals

Question 1

what two viruses is aciclivor used for

Answer 1

herpes simplex
varicella zoster virus

including: genital herpes, cold sores, shingles, chickenpox, encephalitis, etc.

Question 2

what is herpes blepharitis

Answer 2

chronic form of herpes eye infection

Question 3

what is valaciclovir

Answer 3

herpes pro drug

also CMV

Question 4

how is CMV treated in immunocompromised patients

Answer 4

ganciclovir and valganciclovir

Question 5

give examples of DNA viruses

Answer 5

HSV and HPV

Question 6

What is positive sense RNA

Answer 6

similar to mRNA and can be immediately translated by the host cell

Question 7

what enzyme is used to convert negative sense RNA to positive sense

Answer 7

RNA polymerase

Question 8

what is retrovirus

Answer 8

creates a DNA copy of the viral RNA using reverse transcriptase which is found in the virus

some retroviruses can transform normal cells into cancer cells (Human T cell leukaemia virus)

Question 9

what is a provirus

Answer 9

when the viral DNA has been incorporated into the genome of the host cell from a retrovirus

Question 10

how do nucleoside reverse transcriptase inhibitors work

Answer 10

inhibit viral DNA synthesis by acting as a chain terminator

they look like thymidine so replace it but the chain is unable to continue after

Question 11

how do non nucleoside reverse transcriptase inhibitors work

Answer 11

binding denatures the reverse transcriptase enzyme meaning the enzyme cannot produce viral DNA

Question 12

name some NRTIs (nucleoside analogues)

Answer 12

zidovudine
abacavir
lamivudine 
didanosine
zalcitabine 
stavudine 

all have a 5’ trisphosphate group which can bind but do not offer the 3’ function which is required for attachment

require phosphorylation by viral/ cellular kinases

Question 13

name some antiviral nucleoside analogues

used to treat HIV, herpes, RNA viruses

Answer 13

AZT (azidothymidine)
ganciclivor
ribavarin
acyclovir

Question 14

how do protease inhibitors work

Answer 14

HIV codes for inert proteins which are then converted to functional proteins by proteases (virus specific)

protease inhibitors block these enzymes so the virus cannot produce functional proteins

Question 15

name some protease inhibitors

Answer 15

atazanavir, indinavir, lopinavir, ritonavir, saquinavir

Question 16

what are the 6 classes of antiretroviral drugs

Answer 16

nucleoside analogues (RTI)
non nucleoside analogues (RTI)
Protease inhibitors
entry inhibitors
fusion inhibitors
integrase inhibitors

Question 17

what are integrase inhibitors

Answer 17

Blocks the insertion of the viral DNA into the host DNA thereby stopping formation of the provirus

Question 18

name an integrase inhibitor

Answer 18

raltegravir
elvitegravir
dolutegravir

Question 19

what is a fusion inhibitor

Answer 19

blocks binding, fusion and entry of HIV into a cell

receptors: CD4, CCR5 or CXCR4

Question 20

name some fusion inhibitors

Answer 20

maraviroc: CCR5 antagonist

enfuvirtide binds to gp41

Question 21

what is HAART

Answer 21

Combination of 3-4 different drugs, usually 2x NRTIs + NNRTI, PI or integrase inhibitor

Question 22

how do amantadine and rimantadine work (viral uncoating)

Answer 22

amatidine blocks a viral ion channel

rimantadine is concentrated in lysosomes and increases the ph of the compartment, which inteferes with the fusion of lysosomes and endocytosis of viral containing vesicles

Both block M2 ion channel functions

Question 23

how do influenza inhibitors work

Answer 23

NA- neuraminidase blocker

cleaves sialic acid from the cell surface so that newly made viruses are released

NA inhibitors mimic sialic acid substrate by binding to the NA active site which halts viral replication

Question 24

name some NA inhibitors

Answer 24

zanamivir (nasal spray)

tamiflu (tablet)

Question 25

what drugs can be used to treat hep C

Answer 25

ribavirin
pegylated interferon alpha
simeprevir
protease inhibitors