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

Question 1

mechanism of action of Acyclovir, Valacyclovir, and Famciclovir

Answer 1

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

Question 2

how is Acyclovir given?

Answer 2

topical, oral, IV

Question 3

how can we reduce Cidofovir’s toxic renal effects?

Answer 3

co-administration with probenecid

Question 4

which agent has the highest bioavailability- acyclovir or Valaciclovir?

Answer 4

valaciclovir–> 70%

acyclovir–> 15%

Question 5

what is the 1st line agent for CMV?

Answer 5

Ganciclovir

treatment and prophylaxis

Question 6

list the antiviral agents used for VZV

Answer 6

acyclovir
valaciclovir
famciclovir
ganciclovir

Question 7

when do we give IV acyclovir

Answer 7

HSV encephalitis and neonatal infection

Question 8

when do we use acyclovir?

Answer 8

HSV-1, HSV-2, VZV

prophylaxis for immunocompromised

Question 9

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

Answer 9

valaciclovir

acyclovir is short

Question 10

when is valaciclovir &famciclovir used?

Answer 10

VZV (including shingles)

Question 11

what is the function of antiherpetic agents?

Answer 11

antimetabolites

except Foscarnet!!

Question 12

what are the indications for giving Ganciclovir

Answer 12

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

Question 13

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

Answer 13

renal

directly proportional to creatinine clearance

Question 14

what are the side effects of Ganciclovir

Answer 14

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

Question 15

in which agent is it important to maintain hydration?

Answer 15

Cidofovir

Question 16

what does Cidofovir do?

Answer 16

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

Question 17

what is the resistance mechanism of Cidofovir and Foscarnet?

Answer 17

changes in DNA polymerase gene

Question 18

what is the mechanism of Foscarnet

Answer 18

inhibits viral RNA and DNA polymerase

Question 19

what is the 2nd line agent for CMV?

Answer 19

foscarnet

treatment and prophylaxis

Question 20

when do we give Cidofovir?

Answer 20

HSV
CMV
Adenovirus
HPV

Question 21

how are Cidofovir and Foscarnet given?

Answer 21

IV

Question 22

what are the indication for Foscarnet

Answer 22

CMV (2nd line)

HSV

Question 23

Which agents are active against many acyclovir-resistant strains?

Answer 23

Valaciclovir
Cidofovir
Foscarnet

Question 24

what is the SE of Cidofovir?

Answer 24

nephrotoxicity

Question 25

what agents have an additive effect with Cidofovir?

Answer 25

amphotericin B and aminoglycosides | causing NEPHROTOXICTY

Question 26

what are the SE's of Foscarnet

Answer 26

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

Question 27

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

Answer 27

Pentamidine IV

Question 28

what are Amantadine and Oseltamivir?

Answer 28

anti-influenza agents

Question 29

is resistance to amantadine common?

Answer 29

yes

Question 30

is resistant to Oseltamivir common?

Answer 30

no

Question 31

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

Answer 31

Oseltamivir Zanamivir *mainly prophylaxis

Question 32

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

Answer 32

2-3 days

Question 33

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

Answer 33

1-2 days

Question 34

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

Answer 34

Amantadine

Question 35

how are anti-influenza agents given?

Answer 35

orally zanamivir--> inhalation

Question 36

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

Answer 36

Amantadine | Rimantadine

Question 37

what is the mechanism of action of Amantadine?

Answer 37

inhibit M₂ protein--> inhibits viral RNA transcription

Question 38

what is the mechanism of action of Oseltamivir?

Answer 38

inhibit neuraminidase --> promote virion release

Question 39

what are the side effects of Amantadine

Answer 39

atropine-like effects livedo reticularis GI distress Dizziness

Question 40

what are the side effects of Oseltamivir

Answer 40

GI distress | flu-like symptoms

Question 41

what are the Anti-RSV agents?

Answer 41

Palivizumab Ribavirin Pal Riba..

Question 42

how is Palivizumab given?

Answer 42

parenteral

Question 43

what is Palivizumab and what does it target?

Answer 43

its a Humanized monoclonal Ab | targets the A- antigen of fusion protein in RSV

Question 44

when do we give Palivizumab?

Answer 44

prophylaxis in high-risk infants and children: - prematurity - congenital heart disease - bronchopulmonary dysplasia

Question 45

what are the side effects of Palivizumab?

Answer 45

upper respiratory tract infection, rhinitis fever diarrhea vomiting