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.Pharmacology > Part 6: Antiviral agents > Flashcards

Part 6: Antiviral agents Flashcards

1
Q

viruses use host cell ____ and ____ to reproduce

A

biochemica pathways and replication machinery

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2
Q

many viruses are catergorized into 2 groups ___

A

RNA and DNA viruses

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3
Q

Herpes simplex virus, and varicella zoster virus are examples of ____ type viruses

A

DNA

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4
Q

HIV, Hepatitis, Influenza, SARS-CoV2 are examples of ___ type viruses

A

RNA

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5
Q

what are reverse transcribing viruses?

A

RNA viruses that use an enzyme (reverse transcriptase) to create viral DNA that is integrated into the host genome prior to replication

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6
Q

what enzyme is used by reverse transcribing viruses

A

reverse transcriptase

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7
Q

give an example of a reverse transcribing virus

A

HIV

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8
Q

why is it so hard to target viruses with drugs?

A

because they are simplistic mOs that use host materials; and many of them mutate extensively

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9
Q

1st step for viral infection

A

viral attachment and entry into host cells

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10
Q

2nd step for viral infection

A

genetic material is released intto the cytoplasm (uncoating)

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11
Q

3rd step for viral infection

A

once all the componenets are in the cytoplasm, replication begins

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12
Q

replication process depends on the virus, but in general, there are a few viral and host ____ and ____ involved

A

enzymes and replication machinery

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13
Q

4th step in viral infection

A

new viral particles are packaged and released to infect other host cells

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14
Q

what happens to the host cel during viral infection?

A

functions become impaired and are often killed in the process

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15
Q

if the host cell is not destryed by the virus, it may express____ on its surface

A

viral proteins

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16
Q

what is the point of a host cell displaying viral proteins on its surface?

A

causes the immune system to recognize the virus and begin to kill any cells with the antigen

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17
Q

t/f the immune response to viruses can oftne cause significant damage to our host cells as well

A

true

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18
Q

vira; drugs that have been optimized for pharmacological treatment often involve targetting _____ or ____

A

the virus entering or exiting the host cells

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19
Q

some antiviral work by rying to increase the host ___

A

immune response

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20
Q

what are immunomodulators?

A

pharm agents that interact with cells of the immmune system to boost the responsiveness and promote recognition of foreign agents

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21
Q

____ are a more specific approach to prime the immune system and promote memory of an infectious agent to facilitate a larger scale immune response should the infection ever show up

A

vaccinations

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22
Q

give an example of a drug used to treat herpes simplex virus

A

acyclovir

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23
Q

give 2 examples of drugs used to treat hepatitis C

A

ribavirin, IF-A

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24
Q

give 3 examples of drugs used to treat HIV

A

maraviroc, emtricitabine etravirine

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25
Q

give an example of a drug used to treat influenza

A

oseltamavir

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26
Q

give 3 examples of drugs used to treate COVID

A

remdeivir, hydroxychloroquine, bamlanivimab

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27
Q

what do DNA viruses like HSV do once theyve entered a host cell?

A

use a combo of host and their own enzymes to replicate their DNA and create new particles

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28
Q

acyclovir is an antiviral drug that is a ____ analogue

A

guanosine nucleoside

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29
Q

acyclovir is similar enough to endogenous nucleosides that they are incorporated into the ____

A

viral DNA

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30
Q

adding acyclovir into the viral DNA strand, what happens?

A

acyclovir is missing the key group in adding the next nucleotide, the chain will be ended

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31
Q

acyclovir binds to the viral ___ complex to be added to the growing viral DNA strand

A

DNA polymerase

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32
Q

t/f acyclovir bind more strongly than endogenous nucletides so the DNA polymerase complex does not dissociate as easily

A

t

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33
Q

what is the significance of acyclovir binding to DNA polymerase?

A

inhibits progression of viral DNA synthesis and prevents the virus from replicating in the host cell

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34
Q

the mechanims of acyclovir and similar drugs is specific to the viral DNA replication process because the first step in creating the _____ is catalyzed by a viral enzyme, not a host enzyme

A

nucleotide monophosphate

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35
Q

t/f the host-made nucleotides will not contain acyclovir, only the viral ones

A

true

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36
Q

t/f HSV cannot be completely cleared from the host, but can be managed to an asymptomatic level

A

t

37
Q

HSV infections are more easily transmited from ___- sores containing high # of viral particles

A

open

38
Q

how can resistance to nucleoside analogues like acyclovir happen?

A

mutations of viral enzymes responsible for incorporating acyclovir into nucleotides ; mutations in DNA polymerase

39
Q

ribavirin is a ____ analogue

A

nucleoside

40
Q

Ribavrin gets incorporated into the ____ and impairs ___

A

viral synthetic pathways; viral RNA synthesis

41
Q

ribavirn becomes a ___ nucleotide inside the cell

A

phosphorylated

42
Q

interferon ___ has been shown to have benefit in patients with hepatitis C infections

A

alpha

43
Q

interferons increase the activation of host ____ cells which recognize foreign bodies and infected host cells and destroy them

A

cytotoxic T

44
Q

why are interferons not commonly used?

A

non-specific activation of immune system causes systemic effects

45
Q

Maraviroc is an antiviral agent that blocks ____ receptors on the surface of host cells

A

CCR5

46
Q

what is the purpose of Maraviroc binding to the CCR5 receptors on host cells?

A

prevents HIV from entering the host cell

47
Q

t/f not all HIV strains bind to the CCR5 receptor, so Maraviroc does not always work

A

t

48
Q

is Maraviroc approved in Canada for prophylactic HIV?

A

no

49
Q

____ and ___ inhibitors can also be used to reduce the replication of HIV within host cells and release of viral particles

A

integrase and protease

50
Q

___ is the key enzyme in the replication of HIV

A

reverse transcriptase

51
Q

the ____ enzyme was one of the first targets addressed by HIV treatment

A

reverse transcriptase

52
Q

there are 2 classes of reverse transcriptase inhibitors: ___ and ___

A

nucleoside type (NRTIs) and non-Nucleoside type (NNRTIs)

53
Q

give an example of an NRTI

A

emtricitabine

54
Q

give an example of an NNRTI

A

etravirine

55
Q

what is Emtricitabine?

A

NRTI, nucleoside reverse transcriptase inhibitor

56
Q

Emtricitabine is converted to ____ inside cells

A

triphosphate nucleotides

57
Q

MOA of NRTIs

A

structurally similar to endogenous nucleosides and get incorporated into the HIV viral DNA, resulting in chain termination

58
Q

emtricitabine has a similar MOA as ____

A

acyclovir

59
Q

do NNRTIs resemble nucleosides?

A

no

60
Q

NNRTIs are not structurally similar to nucleosides, but have high affinity for ____

A

HIV reverse transcriptase enzyme

61
Q

MOA of Etavirine?

A

inhibits the enzymatic action of reverse transcriptase, preventing the production of HIV viral DNA in host cells

62
Q

t/f reverse transcriptase inhibitors are usually given in combination with other anti-HIV agents to attack the virus from multiple aspects of replication

A

t

63
Q

t/f in some situations, multiple reverse transcriptase inhibitors are used togther in attempt to counteract HIV mutations and resistance to single agenst

A

t

64
Q

the yearly flu vaccine is based on predictions of ___

A

which strains will be the most problematic this year

65
Q

what is neuraminidase?

A

one viral enzyme expressed by influenza that can be targetted

66
Q

____ is the viral enzyme required to allow the newly synthesized influenza particles to be released from the host cell

A

neuraminidase

67
Q

why is neuraminidase required for influenza to release viral particles?

A

our human cells dont bud or release little packages

68
Q

give an example of a neuraminidase inhibitor

A

oseltamavir (tamiflu)

69
Q

oseltamavir has been shown to be effective at reducing the severity of ____ and ____ infections if administered early

A

influenza A and B

70
Q

ideally, oseltamivir needs to be taken within ___ hrs of exposure to influenza or within ___ hrs of onset of symptoms

A

48; 24

71
Q

explain the replication process of COVID

A

virus enters cells by binding to angiotensin converting enzyme 2 (ACE) receptors, internalized, virla RNA is released from endosomes into the host cell cytoplasm where the viral genome is replicated and packaged into new particles for release and more infection

72
Q

what re 2 drug currently being discussed wrt COVID?

A

remdesivir and hydroxychloroquine

73
Q

what is remdesivir?

A

antiviral developed as potnetial treatmet for Ebolsa, now as potnetial for COVID

74
Q

what is hydroxychloroquine?

A

antimalarial drug now considered for COVID

75
Q

what type of antiviral is remdesivir?

A

nucleoside analogue

76
Q

resdemavir has structural similarities to ___

A

adenosine

77
Q

how does resdemavir work>

A

remdesivir nucleoside is processed during viral nucleotide biosynthesis ans is incorporated into the viral RNA, causing chain termination and preventing replication

78
Q

is resdemavir approved in Canada for COVID?

A

yes, with several conditions , includin gwithdrawing approval if ADRs occur

79
Q

hydroxychloroquine is used in some autoimmune diseases such as ___

A

Lupus

80
Q

does hydroxychloroquine have scientific evidence to support its use in COVID?

A

no

81
Q

t/f the antiviral actions of hydroxychloroquine are not as well understood as those of remdesivir

A

t

82
Q

what is the proposed antiviral mechanism of hydroxychloroquine?

A

reduce viral endosome acidification, which prevents the viral components from being relased into the host cell cytoplasm

83
Q

what are some of the ADRs of hydroxychloroquine?

A

irreversible blindness and possibly life-threatening arrhythmias, GI disturbances, neurologic effcets

84
Q

what drug was Trump given for COVID?

A

REGN-COV2

85
Q

what is an example of a neutralizing antibody used to treat COVID?

A

bamlanivimab

86
Q

neutralizing antibodes used for COVD bind to the __

A

spike protein

87
Q

MOA of neutralizing antibodies in treatment of COVID

A

binds to spike protein, prevents entry of the virus into the host cells, reduces ciral replication, and then has cell get recognized by immune system

88
Q

protective immunity wears off over time and is ineffective when viruses ___

A

mutate

.Pharmacology (55 decks)

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