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Flashcards in 4/25 Antivirals Deck (45)
1

name 2 neuraminidase inhibitors

Oseltamivir
Zanamivir

2

MoA of Oseltamivir or Zanamivir

Inhibits influenza neuraminidase -> decrease release of virus

3

difference between Oseltamivir or Zanamivir?

Oseltamivir – oral drug
Zanamivir – inhaler; limited use in young children or patients who are unable to follow instructions

4

indications for Oseltamivir or Zanamivir?

influenza A/B (trmt/prevention)

5

name nucleotide analogs (at least 5)

Ribavirin
Acyclovir
Famciclovir
Valacyclovir
Ganciclovir
Valganciclovir

6

MoA of Ribavirin?

nucleotide analog that inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase (prevents ribosomes from binding to viral RNA)

7

half-life of Ribavirin?

long half-life (stored in RBC and released over days)

8

Indications for Ribavirin?

RSV
HepC (chronic)

9

ADRs of using ribarivin?

Hemolytic anemia
Teratogen
Gout

10

What are 2 alternate drugs that are within the same class as acyclovir?

Famciclovir
Valacyclovir (pro-drug)

11

MoA of Acyclovir?

Guanosine analog; phosphorylated by HSV/VZV–TK and subsequently phosphorylated by host enzymes to form a triphosphate

preferentially inhibits viral DNA polymerase chain termination (virus must be actively replicating; NO effect on latent forms)

12

Why should you be be considered when you prescribe acyclovir?

does the patient have renal failure?
renally excreted, therefore dose must be adjusted for patients with renal insufficiency

13

compare oral bioavailability between acyclovir and the 2 alternate drugs that are within the same class

acyclovir: not great

valacyclovir: oral pro-drug of acyclovir; better oral bioavailability

famciclovir: best oral bioavailability

14

Indications for acyclovir? valacyclovir?

HSV (mucocutaneous and genital lesions, encephalitis, pregnant women/neonatal, prophylaxis in immunocompromised patients) = oral acyclovir or valacyclovir

VZV (healthy, immunocompromised, pregnant women/neonates) = valacyclovir*, acyclovir

VZV, uncomplicated = famciclovir

CMV – weak activity

15

when would you normally prescribe famciclovir?

VZV (according to first AID)

16

Mechanism of resistance for Acyclovir et al?

Mutated viral TK
(common among immunodeficient patients, eg AIDs patients, who receive ACV for prolonged periods)

17

Side effect of Acyclovir et al?
What can you do to prevent this?

Nephropathy due to obstructive crystalline formation; can progress to acute renal failure if not adequately hydrated

CNS disturbances

18

What is an alternate drug that is within the same class as Ganciclovir?

Valganciclovir

19

What is the mxn of ganciclovir?

Guanosine analog that is converted to 5MP by CMV viral kinase and subsequently phosphorylated by host enzymes to form a triphosphate
preferentially inhibits viral DNA polymerase

20

why is ganciclovir more toxic than acyclovir?

more toxic to host enzymes than acyclovir because it can actually be incorporated into DNA, thereby inhibiting HOST kinases and DNA polymerases

21

What is valganciclovir?

valganciclovir is a pro-drug of ganciclovir; better oral bioavailability

22

Indications for ganciclovir?

CMV*
HSV
EBV

23

mechanism of resistance for ganciclovir?

UL97 mutated CMV DNA polymerase or lack of viral kinase

24

side effects of ganciclovir?

Bone marrow suppression
- Leukopenia
- Neutropenia
- Thrombocytopenia
Renal toxicity
Teratogen

25

What is Foscarnet?

Pyro"fos"phate inhibitor that binds to the pyrophosphate-binding site of DNA polymerase; does not require activation by viral kinase

26

Indication for Foscarnet?

Ganciclovir-resistant CMV retinitis
Acyclovir-resistant HSV

27

Mxn of resistance for Foscarnet

mutated DNA polymerase

28

ADR for foscarnet?

Nephrotoxicity
Sequesters divalent cations --> Hypo-Ca, Hypo-PO4, Hypo-Mg

29

Mxn of Cidofovir?

Nucleotide analog that inhibits viral DNA polymerase; does not require activation by viral kinase

10-100x more active against CMV in vitro

30

Half-life of Cidofovir?

long half-life

31

Indications for Cidofovir?

Ganciclovir-resistant CMV
Acyclovir-resistant HSV
Molluscum contagiosum
Pox viruses (small pox, vaccinia, monkeypox)

32

Mxn of resistance for Cidofovir?

Mutated DNA polymerase

33

Side effect of Cidofovir? ways to prevent it from happening?

Nephrotoxicity (coadminister with probenecid and IV saline to toxicity)

34

What is Interferon α and its mechanism of action?

glycoproteins with anti-viral and anti-tumor properties; inhibits viral replication and promotes cytotoxic T cell and NK cell activity

35

Indications for Interferon α?

Hep B, C
Kaposi Sarcoma
Hairy cell leukemia
Conyloma acuminatum

36

Side effects of Interferon α?

Neutropenia
Myopathy
Flu-like symptoms

37

What are Boceprevir and Telapravir?

Protease inhibitor that forms a covalent bond with NS3 protease and prevents it from cleaving the HCV polyprotein into functional viral proteins

38

Indications for Boceprevir and Telapravir?

HCV – one very specific type only

39

ADR for Boceprevir and Telapravir?

Boceprevir – anemia, pancytopenia
Telapravir – anemia, pruritus, skin rash

40

Influenza

Primary treatment

Zanamivir
Oseltamivir

41

HSV

Primary treatment
Alternate Drugs
Drugs for resistant strains

Acyclovir

Famciclovir
Valacyclovir

Cidofovir
Foscarnet

42

VZV

Primary treatment
Alternate Drugs

Famciclovir*
Acyclovir

Valacyclovir

43

CMV

Primary treatment
Alternate Drugs

Ganciclovir

Valganciclovir –prophylaxis in immunocompromised hosts

Cidofovir
Foscarnet

44

HepB

Primary treatment
Alternate Drugs
Drugs for resistant strains

Interferon α
adefovir
emtricitabine
tenofovir
entecavir
telbivudine

45

HepC

Primary treatment
Alternate Drugs

Interferon α + Ribavirin

Boceprevir
Telapravir