1. Antivirals Flashcards

1
Q

What is an antiviral?

A

A drug that is effective against viruses by killing them/suppressing their ability to replicate.

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2
Q

How many people were living with AIDS worldwide in 2012? How many were newly infected?

A
  1. 3 million

- 2.3 million newly infected

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3
Q

What happens to CD4+ T cells after infection with HIV?

A

Initially decrease (~6 weeks)

  • then increase
  • then gradually decrease over years&raquo_space; death
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4
Q

What happens to the number of copies of HIV RNA once infected?

A

Initially increase rapidly (~6 weeks)

  • then decrease
  • years later increase again&raquo_space; death
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5
Q

What type of molecule tends to cause acute viral infections?

A

RNA

-don’t survive well

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6
Q

Give some examples of acute viral infections.

A

Influenza, measles, mumps, hep A

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7
Q

What type of molecule tends to cause chronic viral infections?

A

DNA

-relatively stable

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8
Q

How is HIV different from most chronic viral infections?

A

Caused by single-stranded RNA, but is copied to DNA during replication

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9
Q

What are the 2 types of chronic infection?

A

Latent (lying dormant)

Persistent (continuing to exist)

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10
Q

Give some examples of latent chronic viral infections.

A

Herpes simplex, cytomegalovirus

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11
Q

Give some examples of persistent chronic viral infections.

A

HIV, hep B, hep C

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12
Q

What do viruses consist of?

A

Nucleic acid (DNA/RNA)
Protein (coat/enzymes)
+/- Lipid envelope

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13
Q

What sort of parasite are viruses?

A

Intracellular

-they only replicate in cells

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14
Q

What are the 2 types of proteins that most viruses are composed of?

A

STRUCTURAL (core proteins - GAG, envelope proteins - ENV)

NON-STRUCTURAL (enzymes -POL)

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15
Q

What are the stages of viral replication? (8)

A
  1. Virus attaches to cell (receptor)
  2. Cell entry
  3. Virus uncoating
  4. Early protein production (viral enzymes)
  5. Replication
  6. Late transcription/translation (viral structural proteins)
  7. Virus assembly
  8. Virus release
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16
Q

Do most viruses kill the cells they infect?

A

No, they get released and&raquo_space; infect other cells

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17
Q

How do we use the proteins that viruses encode to treat viral infections?

A

They are unique proteins, so they are targets for molecular inhibition (anti-viral activity)

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18
Q

What are the reactions that polmerases catalyse? (4)

A
  • DNA to DNA
  • DNA to RNA
  • RNA to RNA
  • RNA to DNA
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19
Q

Where are DNA to DNA/RNA polmerases found?

A

Eukaryotes

DNA viruses

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20
Q

Where are RNA to RNA polmerases found?

A

RNA viruses

-not eukaryotes

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21
Q

Where are RNA to DNA polymerases found?

A

Retroviruses (HIV)
Hep B
(-not eukaryotes)

22
Q

What type of drug is azidothymidine (AZT)?

A

Nucleoside Reverse Transcriptase Inhibitor (NRTI).

23
Q

What was azidothymidine developed as, and what is it now used to treat?

A
  • Developed as an anti-cancer drug, but too toxic against normal cells
  • Now used to slow progressions of HIV as it works at lower concentrations (but it can become resistant)
24
Q

What are NRTIs?

A

Nucleoside Reverse Transcriptase Inhibitors

- antiretroviral drugs used to treat HIV

25
What are the main types of NRTIs?
- PYRIMIDINE ANALOGUES (thymidine & cytosine) | - PURINE ANALOGUES (adenine & guanidine)
26
Give 2 examples of pyrimidine analogues.
THYMIDINE: Zidovudine CYTOSINE: Lamivudine
27
Give 2 examples of purine analogues.
Abacavir | Tenofovir
28
Which NRTIs are also effective against Hepatitis B, and why?
Lamividine & tenofovir | -Hep B contains reverse transcriptase enzyme
29
What are NNRTIs and how do the work?
Non-Nucleoside Reverse Transcriptase Inhibitors. | -also inhibit reverse transcriptase (HIV prevention)
30
Give 2 examples of NNRTIs.
Efavirenz | Nevirapine
31
What are protease inhibitors (PIs)?
``` A class of antiviral drug commonly used to treat HIV and hepatitis. -Inhibit unique proteases in viruses ```
32
Give some examples of protease inhibitors.
``` Atazanavir Darunavir Lopinavir Nelfinavir Ritonavir ``` -NB. -avir
33
What is special about Ritonavir as a protease inhibitor?
It inhibits liver enzymes that break down other antivirals, so is used to "boost" the levels of other PIs.
34
Name 3 newer HIV drugs.
- Fusion inhibitors - Integrase inhibitors - Chemokine receptor antagonists (co-receptor)
35
Give an example of a fusion inhibitor (HIV drug).
Enfuviritide | -T20, given by IM injection
36
Give an example of an integrase inhibitor (HIV drug).
Raltegravir | -prevent replication/fusion of the genome
37
Give an example of a chemokine receptor anatagonist (HIV drug).
Maraviroc (CCR-5) | -blocks entry to cells
38
What does HAART stand for?
Highly Active Anti-Retroviral Therapy
39
What does HAART consist of?
- 2 NRTIs & NNRTI | - 2 NRTIs & boosted PI
40
When is HAART used?
HIV treatment. Started when CD4+ decreases and taken lifelong -aims to decrease viral load & prevent additional infection
41
How many nucleotides does the HIV genome contain?
~9000 nucleotides | -each contains 1+ mutations >> more adaptability to change
42
What HIV mutation results in resistance to Lamivudine?
M184V mutation
43
How could HIV potentially be cured?
Supressed on antivirals & destroy existing CD4 lymphocytes by conditioning >> stem cells restored by donor
44
What would be the criteria for an HIV stem cell donor?
- HLA-matched | - Delta 32 homozygous allogenic
45
What are interferons?
Proteins released by animal cells that inhibit viral replication (naturally occurring antivirals).
46
How is hepatitis C treated?
Interferons & ribavirin. | - must be given from 3-12 months & can >> depression
47
What are the 5 important antivirals?
``` Aciclovir Ganciclovir Oseltamivir & Zanamavir Ribavirin Interferons ```
48
What is Aciclovir used to treat?
Herpes Simples (Rx) Varicella Zoster (nucleoside analogue)
49
What is Ganciclovir used to treat?
Cytomegalovirus
50
What are Oseltamivir & Zanamavir used to treat?
Influenza
51
What is Ribavirin used to treat?
Hepatitis C | RSV
52
What are Interferons used to treat?
Hepatitis C | Hepatitis B