Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

PCH 511 > Antivirals > Flashcards

Antivirals Flashcards

1
Q

WHAT ARE VIRUSES?

A

They are obligate intracellular parasites, which largely depend on the host cell metabolic machineries for their survival and replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why can’t you kill a virus?

A

They are active internally, so if you attack a virus with the intention of killing it, you
will kill the host. Viruses are best treated by inhibition of action.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A viral life cycle consists of 6 steps. What are they?

A
  1. Attachment
  2. Viral Entry
  3. Uncoating
  4. Replication
  5. Protein synthesis/assembly
  6. Release of new viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain the attachment phase.

A

This is the attachment of the viral particle to the membrane of the host cell. It is a highly
specific process mediated by some molecules on the surface of the viral protein coat or lipid envelop recognizing specific binding sites on the host cell. The specificity of this process is responsible for the tissue-specificity of most
viral infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain viral entry

A

Refers to the penetration of the viral particle into the cytoplasm of the host cell. Viral entry
can be through endocytosis, membrane fusion, or both.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain uncoating

A

Removal of the protein coat together with any additional covering (if any) from the viral
genome after its successful entry into the cytoplasm. This release of viral genome, also called uncoating, is normally followed by the replication stage of the life cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain replication

A

Nucleic acid replication or synthesis refers to the production of many copies of the viral
genome (DNA or RNA).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain protein synthesis and assembly

A

This refers to the synthesis of messenger RNA by DNA viruses (nucleic acid transcription), formation, assembly into the capsid, and release of new viral cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain the release of new viruses

A

Infective viral particles from the cell by budding from the cell membrane or rupture
of the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Classify antiviral drugs based on chemical structure

A
  1. Admantane drugs: Amantadine, Rimantadine
  2. Purine nucleosides: Inosine and its derivative inosiplex, acyclovir and gancyclovir
  3. Pyrimidine nucleosides: Zidovudine, Idoxuridine, Trifluridine
  4. Phosphorus derivatives: Foscarnet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Classify antivirals based on MOA

A
  1. Entry inhibitors: Maraviroc (CCR5 antagonist)
  2. Fusion inhibitors: Enfuvirtide
  3. Uncoating inhibitors: Amantadine, Rimantadine
  4. Reverse transcriptase inhibitors:
    a) NRTIs: Zidovudine, Lamivudine
    b) NNRTIs: Nevirapine, Ateviradine
  5. DNA polymerase inhibitors: Idoxuridine, Foscarnet
  6. Protease inhibitors: Ritonavir, Atovanavir, and Saquinavir
  7. Integrase inhibitors: Raltegravir
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Amantadine Hydrochloride
is the hydrochloride salt of

A

1-adamantamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the uses of amantadine?

A
  1. It is therefore used for the prophylaxis or treatment of early infection with influenza A.
  2. It is also used to treat Parkinson’s disease.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name three brands of amantadine

A

Gocovri, Symadine, and Symmetrel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the major drawback of amantadine?

A

It has a major drawback of causing stimulation of dopamine in the central nervous system, which can result into anxiety, depression or even hallucinations in addition to other minor central side effects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain the SAR of amantadine

A
  1. Replacement of the amino group with OH, SH, CN, or halogen results in an inactive compound.
  2. However, alkyl derivatives exhibit antiviral activity.
  3. But N-Acyl derivatives show reduced antiviral activity except glycyl derivatives.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the IUPAC name of rimantadine?

A

α-methyl-1-adamantane methylamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does rimantadine have less side effects than amantadine?

A

The additional alkyl group introduced makes it susceptible to hepatic metabolic enzymes that metabolize it into a form that cannot cross the blood-brain barrier.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is rimantadine used for?

A

Rimantadine is used to prevent or treat certain influenza (flu) infections (type A) in adults (17 years of age and older).

It is also used to prevent flu infection (type A) in children (1 to 16 years of age).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Amantadine and rimantadine are what type of inhibitors?

A

M2 protein inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which purine nucleosides are DNA polymerase inhibitors?

A

Acyclovir, Valacyclovir, and Ganiciclovir

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the characteristics of inosine?

A
  1. Found in RNA, all living things
  2. Used for production of uric acid
  3. Made in a lab
23
Q

What are the characteristics of inosiplex?

A
  1. Broad spectrum antiviral activity with effect against influenza, RNA viruses, DNA viruses, herpes simples, vaccinia, etc
  2. It is a 1:3 complex of inosine and the -1-
    dimethylamino-2-propanol salt of 4-acetamido
    benzoic acid.
24
Q

What is acyclovir used to treat?

A

Treats herpes, chicken pox, shingles

25
Acyclovir is converted to monophosphate by?
Thymidine kinase (herpes-specific viral protein)
26
Acyclovir monophosphate is then activated to the triphosphate form by?
Cellular kinases
27
Acyclovir is only active against what type of viruses?
Replicating viruses
28
The HCl salt of valacyclovir is used to treat
Shingles infection
29
Explain the SAR of acyclovir
1. Acyclic side chain at N-9 is essential for activity. 2. Absence of CH2OH group from side chain leads to an inactive analogue is obtained. 3. The position 9-alkoxy derivative is highly active against herpes simplex and varicella zoster virus
30
What is the MOA of acyclovir?
Competes with dGTP (guanine triphosphate) for viral polymerase. It then gets incorporated into viral DNA and causes chain termination, inhibiting nucleic acid synthesis.
31
Compare and contrast acyclovir and ganiclovir
1. Ganicyclovir differs from acyclovir by a single carboxyl side chain 2. Ganicyclovir is 50x more potent than acyclovir against cytomegaloviruses due to the absence of thymidine kinase in CMV. 3. Ganiciclovir does not require phosphorylation for producing its action against CMV.
32
What is the IUPAC name of acycloir?
9-(2-hydroxyethoxy)methylguanine
33
Why is acyclovir better than regular cyclic analogues?
Acyclovir is an acyclic analogue. Monophosphorylation must first occur by viral thymidine kinase before it can be further phosphorylated (to triphosphate) by cellular kinases, which is the active form of the drug. This means that the drug will only affect virus-infected cells, resulting in low toxicity.
34
What are th drawbacks of acyclovir?
It is highly polar, and as such, can cross biological membranes.
35
How would you classify pyrimidine nuclosides?
They are NRTIs--false substrates of nucleic acids
36
Give examples of pyrimidine nucleosides
Zidovudine, Lamivudine, Idoxuridine, Trifluridine
37
What is the MOA of pyrimidine nucleosides
They inhibit cell growth and replication by causing chain termination when they are incorporated into a DNA strand.
38
What is the chemical name of zidovudine?
3-azido-2-deoxythymidine (Azidothymidine or AZT for short)
39
SAR of zidovudine
The antiviral activity comes from substituting the OH group on C4 of the deoxyribose sugar of thymidine with an N3 group (azido).
40
Zidovudine was the first antiviral to be approved for the treatment of HIV. True or false?
True
41
Give examples of phosphorus derivatives for antiviral use
Foscarnet
42
What is the MOA of foscarnet?
It binds to enzymes involved in viral DNA synthesis (viral DNA polymerase or HIV reverse transcriptase). This prevents the viral DNA chain from elongating and stops the replication of viruses.
43
What is foscarnet used to treat?
HSV, CMV, and VZV (chicken pox) especially in immunocompromised individuals.
44
Is foscarnet a first-line treatment?
No. Foscarnet is highly nephrotoxic, so it is reserved for when first-line treatment is ineffective.
45
What is the MOA of entry inhibitors?
Entry inhibitrs bind to either host cell receptors (CD4), co-receptors (CCR5), or viral spike protein (gp120), preventing viral attachment into the host cell and therefore preventing entry. NON-ENVELOPED VIRUSES
46
Examples of entry inhibitors
Maraviroc, Ibalizumab
47
What is the MOA of fusion inhibitors?
They bind to gp41 and block HIV from entering a host cell by preventing the viral envelope from fusing with the cell membrane. ENVELOPED VIRUSES
48
What is the difference between entry inhibitors and fusion inhibitors?
They both prevent viruses from gaining access to the host cell, but entry inhibitors prevent non-enveloped viruses from attaching to the host cell surface, while fusion inhibitors prevent enveloped viruses from fusing with the host cell membrane.
49
Examples of fusion inhibitors
Enfuvirtide (Fuzeon) Given as a shot under the skin
50
What is reverse transcriptase enzyme?
It is a variant of DNA polymerase present in viruses that require the production of DNA from an RNA template as part of their life cycle, called Retroviruses.
51
What is the difference between NRTIs and NNRTIs?
NRTIs are false substrates that are incorporated into DNA and cause chain termination. NNRTIs are allosteric binders that bind to reverse transcriptase and cause conformational changes to the active site, preventing it from binding to substrates.
52
Why are NRTIs and NNRTIs used in combination?
The different MOAs that target the same process result in a maximum effect and prevent the development of resistance.
53
Examples of NNRTIs
Nevirapine (Viramune), Ateviridine
54
Why is Nevirapine considered safe for use in babies?
Reverse transcriptase is exclusive to virus-infected cells. Since the drug specifically targets reverse transcriptase, it does not affect human cells and is considered safe to use in newborns in preventing parent-to-child transmission of HIV.

PCH 511 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions