Antivirals Notes Flashcards

1
Q

1) All antivirals are ……

2) No antivirals are ……

A

1) All are virustatic

2) None are virucidal

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2
Q

What type of intracellular parasites are viruses?

A

obligate intracellular parasites

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3
Q

Finish the sentence: As viruses utilise host cell enzymes to replicate……

A

….there are limited viral proteins that are targets for drugs

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4
Q

What is a common side effect to host cells?

A

toxicity to host cell

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5
Q

Are antivirals used in a) a minority or b) a majority of viral infections?

A

MINORITY

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6
Q

Antivirals a) DO b) DO NOT

eradicate virus from latently infected cells (Herpes)

A

b) DO NOT

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7
Q

True or False: Several stages of the life cycle are targets for antivirals (intracellular stages)?

A

TRUE

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8
Q

Do antivirals have a greater effect on a) host cell function or b) viral replication?

A

b) Viral replication

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9
Q

Most antivirals are what type of analogues?

A

nucleoside analogues

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10
Q

What do nucleoside analogues do?

A

they inhibit nucleic acid synthesis

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11
Q

Types of antiviral therapy:

What is prophylaxis?

A

To prevent infection

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12
Q

What is pre-emptive therapy?

A

It is when there is evidence of infection detected before symptoms

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13
Q

Name 4 types of antiviral therapy:

A

1) Prophylaxis
2) Pre-emptive therapy
3) Overt disease
4) Suppressive therapy

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14
Q

What is suppressive therapy?

A

it keeps viral replication below rate at which tissue damage occurs in an asymptomatic infected patient (HIV)

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15
Q

What is overt disease? (This wasn’t in notes)

A

A host-parasite interaction that results in some injury to the tissues of the host. (This was not in notes)

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16
Q

Antivirals for HSV: With what types of presentations of HSV are antivirals used?

A
  • Mucocutaneous: Oral/ Genital/ Eye/ Skin
  • Encephalitis
  • Immunocompromised- any site
17
Q

When are antivirals used in someone who presents with chickenpox (VZV)?

A
  • When it affects neonate/ immunocompromised/ pregnant

- Immunocompromised adult: only effective if the treatment is begun within 24h

18
Q

When are antivirals useful in someone who presents with shingles (VZV)?

A

only decreases post-herpetic neuralgia in immunocompetent host if begun within 72h

19
Q

Name some of the antiviral treatments and their route of administration in HSV + VZV:

A
  • Aciclovir: Oral/ IV/ Eye ointment/ cream
  • Valaciclovir: Oral
  • Famciclovir: Oral
  • Foscarnet: IV

(Aciclovir like drugs are only active in herpes infected cells (low toxicity for normal cells) )

20
Q

Describe Aciclovir’s mode of action: (4 points)

A
  • Aciclovir is converted by viral thymidine kinase to ACVMP
  • ACVMP then converted by host cell kinases to ACV-TP
  • ACV-TP in turn completely inhibits + inactivates HSV-specific DNA polymerase
  • Preventing further viral DNA synthesis without affecting normal cellular processes
21
Q

Antivirals + CMV ( cytomegalovirus):
-All available drugs for CMV have significant toxicity,
when should antivirals be used to treat CMV?

A
  • Only treat life/ sight threatening CMV infections

- May be used to treat neonates with symptomatic congenital CMV infection

22
Q

Name 4 antivirals used in the treatment of CMV and give their routes of administration:

A
  • Ganciclovir: IV/ ocular implant
  • Valganciclovir: Oral
  • Cidofovir: IV
  • Foscarnet: IV
23
Q

Antivirals+ HIV: What is the type of antiviral therapy used in HIV?

A

Combination anti-retroviral therapy (cART)

24
Q

How has cART transformed HIV care?

A
  • Restoration of immune function in AIDS

- Decrease in opportunistic infections

25
What are the antivirals used for chronic Hepatitis B?
* Pegylated interferon alpha (subcutaneous) | * Nucleoside analogues – Tenofovir / Adefovir / Entecavir / Lamivudine / Emtricitabine/ Telbivudine
26
What is the length of time antivirals are used for in Chronic Hepatitis C?
often 12-48 weeks
27
What are the 2 antiviral therapies used for Chronic Hepatitis C?
oPeglycated interferon alpha (subcutaneous) + ribavirin (oral) oAs above plus protease inhibitor (telaprevir / boceprevir)
28
In what respiratory infections are antivirals used?
- Influenza A / B | - Respiratory Syncytial Virus
29
State the antiviral treatment used in Influenza A / B:
• Oseltamivir (Tamiflu) or Zanamivir o Role in both treatment + prophylaxis o Should start within 48 hours of symptom onset / contact
30
State the antiviral treatment used in Respiratory Syncytial virus:
Ribavirin (rarely indicated)
31
What are the 2 categories of antiviral resistance that you can get?
Phenotypic & Genotypic
32
Describe phenotypic resistance to antivirals:
• Phenotypic – Virus can grow in presence of compound (HSV)
33
Describe Genotypic resistance to antivirals:
• Genotypic – Sequence genome + identify resistance associated mutations (HIV)
34
When should you suspect resistance to herpes virus in the immunocompromised?
If no response within 7 days
35
If HSV + CMV are both resistant to aciclovir, what is usually effective next?
Foscarnet is usually effective
36
When is HIV resistance testing performed?
At diagnosis/ failing therapy