CP3 - Antivirals Flashcards

1
Q

what are the two types of viruses?

A

RNA virus and DNa virus

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2
Q

which viruses cause which types of infections?

A

RNA -acute
DNA - Chronic
(as a general rule)

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3
Q

why is there a distinction in timespan of infections caused by RNA and DNA viruses?

A

this is due to the lifespan of DNA and RNA

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4
Q

examples of acute infections caused by viruses

A
  1. influenza
  2. measles
  3. mumps
  4. hep A
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5
Q

when do antivirals need to be administered if they are to be effective?

A

for acute infections, if they are given soon after symptoms develop

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6
Q

examples of chronic latent viral infections

A
  1. herpes simplex virus

2. cytomegalovirus

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7
Q

examples of chronic persistent infections

A
  1. HIV
  2. Hep B
  3. Hep C
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8
Q

what are the cell constituents of viruses?

A
  1. nucleic acid (DNA/RNA)
  2. protein coat
  3. enzymes
  4. may to may not have a lipid envelope
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9
Q

what are the types of genes found in viruses?

A
  1. structural genes - for the functioning of the virus

2. non structural genes - take over the cell

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10
Q

what is the mechanism of replication of viruses?

A
  1. virus enters the body
  2. finds the cell
  3. attaches to a receptor and enters the cell
  4. uncoating of the virus
  5. viral enzymes produced using host machinery
  6. replication of enzymes
  7. transcription and translation of structural proteins
  8. assembly of new virus
  9. virus release
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11
Q

what do antivirals target and why?

A

viral proteins because these are unique to viruses and important for their infectivity and replication

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12
Q

why are DNA viruses slightly difficult to tackle?

A

their polymerases are likely to be the same as those in eukaryotic cells
(RNA to RNA polymerases are not found in our body)

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13
Q

what are the constituents of a nucleotide?

A

nitrogen base + ribose sugar +phosphate group

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14
Q

why may antivirals not be completely effective against viruses?

A

enzymes that facilitate viral replication are not highly accurate, and are therefore prone to mutations

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15
Q

what type of antiviral is azidothymidine?

A

nucleoside reverse transcriptase inhibitor

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16
Q

what are the 2 types of NRTIs?

A

purine analogues

pyrimidine analogues

17
Q

name examples of purine analogues

A

analogues for adenine and guanidine - abacavir, tenofovir (end in vir)

18
Q

name examples of pyrimidine analogues

A

thymidine analogue- zidovudine
cytosine analogue - lamivudine
(end in vudine)

19
Q

which are the newer HIV drugs?

A
  1. fusion inhibitor
  2. integrase inhibitor
  3. chemokine receptor antagonists
20
Q

why are some NRTIs effective against Hep B?

A

the virus contains a reverse transcriptase enzyme

21
Q

what are NNRTIs?

A

non nucleoside reverse trascriptase inhibitors

22
Q

how do NNRTIs work?

A

bind directly to the reverse transcriptase and work by non competitive inhibition

23
Q

name examples of NNRTIs

A

efavirenz

nevirapine

24
Q

what are the aims of HAART?

A

Highly active antiretroviral therapy aims to switch off viral replication. lifelong treatment

25
Q

what substances are used to treat Hep C?

A

interferons and ribavirin are used, depending on virus genotype

26
Q

what are interferons?

A

proteins released by animal cells in response to the entry of a virus, to inhibit its replication

27
Q

what is aciclovir used against?

A

herpes simplex virus and varicella zoster

28
Q

what type of drug is aciclovir?

A

nucleoside analogue

29
Q

what is ganciclovir used against?

A

cytomegalovirus

30
Q

what are oseltamivir and zanamavir used against? what type of antivirals are they?

A

influenza

neuraminidase inhibitors

31
Q

what is ribavirin used against?

A

Hep C

Respiratory Syncytial Virus (RSV)

32
Q

what are interferons used against?

A

Hep B

Hep C