C.5.Agents to treat HSV, VZV, CMV, RSV infection. Anti-influenza agents. Flashcards

1
Q

mechanism of action of Acyclovir, Valacyclovir, and Famciclovir

A

thymidine kinase monophosphorylates the agents–> they are bioactivated by host-cell kinases to the triphosphate form
triphosphate form inhibits viral DNA polymerase

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2
Q

how is Acyclovir given?

A

topical, oral, IV

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3
Q

how can we reduce Cidofovir’s toxic renal effects?

A

co-administration with probenecid

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4
Q

which agent has the highest bioavailability- acyclovir or Valaciclovir?

A

valaciclovir–> 70%

acyclovir–> 15%

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5
Q

what is the 1st line agent for CMV?

A

Ganciclovir

treatment and prophylaxis

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6
Q

list the antiviral agents used for VZV

A

acyclovir
valaciclovir
famciclovir
ganciclovir

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7
Q

when do we give IV acyclovir

A

HSV encephalitis and neonatal infection

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8
Q

when do we use acyclovir?

A

HSV-1, HSV-2, VZV

prophylaxis for immunocompromised

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9
Q

which agent has the longest T1/2- Acyclovir or valaciclovir?

A

valaciclovir

acyclovir is short

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10
Q

when is valaciclovir &famciclovir used?

A

VZV (including shingles)

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11
Q

what is the function of antiherpetic agents?

A

antimetabolites

except Foscarnet!!

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12
Q

what are the indications for giving Ganciclovir

A
  1. CNV 1st line
  2. prophylaxis in solid organ and bone marrow transplantation
  3. HSV-1, HSV-2, VZV
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13
Q

what type of elimination do we have in Ganciclovir and Foscarnet?

A

renal

directly proportional to creatinine clearance

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14
Q

what are the side effects of Ganciclovir

A
bone marrow suppression
mucosits, gastroenteritis
hepatic dysfunction
seizures (in overdose)
crystalluria (nephrotoxic)
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15
Q

in which agent is it important to maintain hydration?

A

Cidofovir

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16
Q

what does Cidofovir do?

A

it’s activated by host cell kinase and become diphosphate–> which inhibits viral DNA polymerase

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17
Q

what is the resistance mechanism of Cidofovir and Foscarnet?

A

changes in DNA polymerase gene

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18
Q

what is the mechanism of Foscarnet

A

inhibits viral RNA and DNA polymerase

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19
Q

what is the 2nd line agent for CMV?

A

foscarnet

treatment and prophylaxis

20
Q

when do we give Cidofovir?

A

HSV
CMV
Adenovirus
HPV

21
Q

how are Cidofovir and Foscarnet given?

A

IV

22
Q

what are the indication for Foscarnet

A

CMV (2nd line)

HSV

23
Q

Which agents are active against many acyclovir-resistant strains?

A

Valaciclovir
Cidofovir
Foscarnet

24
Q

what is the SE of Cidofovir?

A

nephrotoxicity

25
Q

what agents have an additive effect with Cidofovir?

A

amphotericin B and aminoglycosides

causing NEPHROTOXICTY

26
Q

what are the SE’s of Foscarnet

A
  1. nephrotoxicity
  2. electrolyte disorders (K+, Mg²+, Ca²+ ↓↓)
  3. genitourinary ulceration
  4. CNS effects
27
Q

which agent when given with Foscarnet against pneumocystis in HIV patients, produces an additive nephrotoxic effect (life-threatening hypocalcemia)

A

Pentamidine IV

28
Q

what are Amantadine and Oseltamivir?

A

anti-influenza agents

29
Q

is resistance to amantadine common?

A

yes

30
Q

is resistant to Oseltamivir common?

A

no

31
Q

which anti-influenza agents are used for Influenza A and B virus?

A

Oseltamivir
Zanamivir

*mainly prophylaxis

32
Q

for how long does Oseltamivir reduce the duration of flu symptoms, when used prophylaxis?

A

2-3 days

33
Q

for how long does Amantadine reduce the duration of flu symptoms, when used prophylaxis?

A

1-2 days

34
Q

which anti-influenza agent has potential use in Parkinson’s disease?

A

Amantadine

35
Q

how are anti-influenza agents given?

A

orally

zanamivir–> inhalation

36
Q

which anti-influenza agents is used only for Influenza A virus?

A

Amantadine

Rimantadine

37
Q

what is the mechanism of action of Amantadine?

A

inhibit M₂ protein–> inhibits viral RNA transcription

38
Q

what is the mechanism of action of Oseltamivir?

A

inhibit neuraminidase –> promote virion release

39
Q

what are the side effects of Amantadine

A

atropine-like effects
livedo reticularis
GI distress
Dizziness

40
Q

what are the side effects of Oseltamivir

A

GI distress

flu-like symptoms

41
Q

what are the Anti-RSV agents?

A

Palivizumab
Ribavirin

Pal Riba..

42
Q

how is Palivizumab given?

A

parenteral

43
Q

what is Palivizumab and what does it target?

A

its a Humanized monoclonal Ab

targets the A- antigen of fusion protein in RSV

44
Q

when do we give Palivizumab?

A

prophylaxis in high-risk infants and children:

  • prematurity
  • congenital heart disease
  • bronchopulmonary dysplasia
45
Q

what are the side effects of Palivizumab?

A

upper respiratory tract infection, rhinitis
fever
diarrhea
vomiting