Anti-Virals Flashcards

1
Q

what are some viral targets for drugs?

A
  • viral capsid proteins
  • viral integrase (HIV)
  • proteases
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2
Q

name some features of viruses

A
  • envelope proteins
  • lipid envelope
  • capsid (protein shell)
  • genetic material (RNA or DNA)
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3
Q

what is the tropism in hepatitis?

A

liver hepatocytes

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4
Q

what sort of hepatitis infection requires treatment?

A

chronic infection only (B and C)

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5
Q

what drugs are used to treat hep B?

A

tenofovir (nucleoTide analogue)

this is for chronic management and is not a cure

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6
Q

what is tenofovir? (HepB)

A

a nucleotide analogue that inhibits reverse transcriptase

given with peginterferon alpha

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7
Q

what drugs are used to treat Hep C?

A
  • Ribavirin (nucleoSide analogue)

- Boceprevir (protease inhibitor)

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8
Q

what is ribavirin?

A

nucleoside analogue
• Purine analogue.
• Given with Peginterferon alfa.

Use for Hep C

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9
Q

what is tenofovir used for?

A
hep B treatment
and HIV (inhibit reverse transcriptase)
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10
Q

what is ribavirin used for?

A

hep C treatment

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11
Q

what is boceprevir used for?

A

hep C treatment

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12
Q

what is boceprevir?

A

protease inhibitor

•Most effective against HepC genotype 1.

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13
Q

how does the hep B and hep C virus differ?

A

hep B is a dsDNA virus while hep C is a ssRNA virus

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14
Q

which hepatitis infection can be cured?

A

C can be cured while B cannot be cured

hep C is given a combo of drugs based on the HCV genotype, viral load, past treatment experience and liver health etc

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15
Q

what are the stages of HIV’s life cycle?

A

1) attachment and entry
2) replication and integration (these can be targetted separately)
3) assembly and release

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16
Q

what happens in the attachment and entry stage of HIV?

A

viral membrane proteins interact and bind leucocyte membrane proteins leading to viral capsid endocytosis.

Use GP120 and GP41

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17
Q

what happens in the replication and integration stage of HIV?

A

reverse transcriptase converts viral RNA to DNA which is integrated into host DNA by HIV integrase

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18
Q

how does HIV enter a cell?

A
HIV GP120 binds CD4 and 
either CCR5 (chemokine receptor) or CXCR4.
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19
Q

what needs to be done for HIV to definitely enter a cell?

A

needs to bind to the chemokine co-receptor CCR5 or CXCR4 alongside the binding to CD4

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20
Q

what part of HIV penetrates the membrane of the host?

A

Gp41

glycoprotein 41: envelope protein complex subunit in retroviruses

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21
Q

what drugs can be used to target the attachment and entry phase of HIV’s life cycle?

A
  • enfuvirtide (binds and inhibits Gp41)

- maraviroc (blocks CCR5 co-receptor)

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22
Q

what does enfuvirtide do?

A

binds to Gp41 of the HIV virus to disable penetration into the host cells membrane

23
Q

what does maraviroc do?

A

blocks to CCR5 so viral endocytosis can not be stimulated

24
Q

how does HIV replicate normally?

A

Reverse transcription

– viral ssRNA becomes dsDNA.

25
Q

what drugs can be used to target HIV replication (reverse transcription) ?

A

o Zidovudine/AZT
– nucleoside RT inhibitor.

o Tenofovir
– nucleotide RT inhibitor.

o Efavirenz
– non-nucleoside RT inhibitor.

26
Q

what is zidovudine?

A

nucleoside RT inhibitor

Activated by a 3-step phosphorylation process.

27
Q

what is tenofovir? (HIV)

A

nucleotide RT inhibitor

Activated by fewer (<3) phosphorylation steps

28
Q

what is efavirenz?

A

non-nucleoside RT inhibitor (use in HIV)

  • No phosphorylation required as it is not incorporated into viral DNA.
  • Binds to RT and changes its conformation
29
Q

which of the drugs that target HIV replication has the least phosphorylation steps?

A

efavirenz (no phosphorylation required)

30
Q

what mutation in some people means they do not become infected by HIV?

A

delta 32 mutation of CCR5

31
Q

what is the effect of having a delta 32 mutation?

A

the cells do not express the chemokine receptor CCR5 and therefore HIV cannot be endocytosed

32
Q

how does HIV integrate its genetic material into the human genome?

A

Viral integrase inserts viral RNA into host DNA.

33
Q

what drugs target HIV integration?

A

Raltegravir – viral integrase inhibitor.

34
Q

what does raltegravir do?

A

viral integrase:

inhibits HIV viral RNA being integrated into human DNA by inhibiting HIV integrase

35
Q

how does HIV assemble and release its virions?

A

o Gag precursor is the precursor for all viral structural proteins.
o HIV protease cleaves the Gag precursor into an active Gag protein to be used for make viral components

36
Q

what drugs target HIV assembly and release?

A
target HIV protease that cleaves Gag precursor
o Saquinavir 
– protease inhibitor
o Low-dose Ritonavir 
– reduces protease inhibitor metabolism.
37
Q

what are the HIV protease inhibitors?

A

o Saquinavir

o Low-dose Ritonavir (booster given to increase concentration of protease inhibitors)

38
Q

what are the HIV integrase inhibitors?

A

Raltegravir

39
Q

what are the HIV replication inhibitors?

A
o Zidovudine (nucleoside RTi)
o Tenofovir (nucleotide RTi) 
o Efavirenz (non-nucleoside RTi)
40
Q

what are the HIV entry inhibitors?

A
o Enfuvirtide (GP41)
o Maraviroc (CCR5)
41
Q

what are the stages of HIV life cycle split up according to drug targeting?

A
  • virus attachment
  • virus entry
  • virus replication
  • virus integration
  • virus assembly and release
42
Q

what sort of virus is Herpes Simplex?

A

dsDNA

like Hep B

43
Q

describe HSV structure

A

o Surrounded by a tegumet & enclosed in a lipid bilayer.

44
Q

what are the tropisms of HSV-1 and HSV-2?

A

o HSV-1 –> cold sores (oral)

o HSV-2 –> genital herpes (genital)

45
Q

how is HSV infection treated?

A

Acyclovir

– nucleoside analogue.

46
Q

what is the difference between a nucleoside and nucleotide?

A

nucleoside= base+ sugar

nucleotide= base+ sugar+phosphate

47
Q

what sort of virus is influenza?

A

ssRNA

like Hep C

48
Q

describe the Influenza structure

A

Envelope proteins neuraminidase (NA) activation leads to release of virus

49
Q

what is the tropism for influenza?

A

Nose, throat and bronchi.

50
Q

what is the treatment for influenza?

A

Oseltamivir

– Neuraminidase inhibitor.

51
Q

what is neuraminidase?

A

enzymes cleave the glycosidic linkages of neuraminic acids.

Found on Influenzavirus

52
Q

what sorts of viruses are the following:

  • HIV
  • Hep B
  • Hep C
  • HSV
  • Influenza
A
  • HIV–> retrovirus
  • Hep B–> dsDNA
  • Hep C–> ssRNA
  • HSV–> dsDNA
  • Influenza–> ssRNA
53
Q

name some nucleoside analogues and the infections they treat

A

ribavirin–> HepC

acyclovir–> Herpes Simplex

54
Q

name a neuraminidase inhibitor and the infection it treats

A

oseltamivir –> influenza