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GI 2 > hepatitis Drugs > Flashcards

hepatitis Drugs Flashcards

1
Q

Biological agents used for treatment of Chronic HBV infection?

Nucleos-(t)ide reverse transcriptase inhibitors?

  • ALL caps the nucleoTIDE
A

-interferon a . . . and Pegylated versions

  • Entecavir
  • TENOFOVIR
  • Lamivudine
  • Telbivudine
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2
Q

Interferon-a formulations, especially PEG-interferons are primarily used for treatment of what patients

A

those with well compensated Liver disease who do not wish to be on long term treatment or are planning to be pregnant within next 2 to 3 years

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3
Q

Side effects of interferon therapy

A
  • flu like syndrome

- DANGEROUS in decompensated cirrhosis

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4
Q

difference in pharmacokinetics b/t interferon and PEG-interferon

A

PEG increases half life and only have to take once a week . . non pegylated interferon is 3x/week

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5
Q

IFN actions on UNINFECTED hepatocytes step by step

A
  • IFN binding activates Jak1 and Tyk2
  • Jak1 and Tyk2 phosphorylate IFN receptor
  • Phospho-IFN receptor recruits STATs
  • Jak1 and Tyk2 phosphorylate STATs
  • Phospho-STATs “undock” from IFN receptor and dimerize
  • they relocalize to nucleus
  • upregulates DNA transcription of interferon stiumlated genes (ISG)
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6
Q

What are the 2 ISGs that are synthesized after interferon binding

A
  • 2,5 oligoadenylate synthetase (2’5’ OAS)

- Protein Kinase R (PKR)

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7
Q

the ISG 2’5’ OAS does what

A

-activates Ribonuclease L –> degrades viral RNA

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8
Q

The ISG PKR does what

A

phosphorylate Elongation initiation factor (EiF) which then inhibits protein synthesis

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9
Q

What is the immunomodulary effect of IFN therapy?

what is the consequence?

A

favors cell mediated immunity TH1 phenotypes to eradicate HBV

increase in inflammation and fibrosis (explains the contraindications)

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10
Q

IFN therapy is contraindicated in what patients

A

those with one or more complication of chronic liver disease such as:

  • ASCITES
  • encephalopathy
  • variceal bleeding
  • COAGULOPATHY
  • HEPATOCELLULAR CARCINOMA
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11
Q

Adverse effects of IFN therapy

A
  • Flu like syndrome
  • fatigue and mental depression
  • Dose limiting toxicity (Bone marrow suppression and neurotoxicity)
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12
Q

explain the mechanism of why tenofovir is used with resistant cells

A

It is already phosphorylated so it can be harbored in cells that have low purine/pyrimidine kinase activity

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13
Q

First line oral Anti-HBV agents

Second line?

A
  • Tenofovir
  • Entecavir
  • Lamivudine
  • Telbivudine
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14
Q

explain the adverse effect of tenofovir and it’s relationship with HIV infected individuals

A

Nephrotoxicity

-more often with HIV because higher doses are used but still encountered without this

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15
Q

What part of the renal tubule is susceptible to Tenofovir toxicity

A

-proximal tubule

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16
Q

Explain Resistance profile to Entecavir

A

-Resistance is rare among Nucleoside-naive patients but resistance occurs in 50% of lamivudine-resistant patients after 5 years of treatment

17
Q

When might Entecavir be a better option than adefovir or tenofovir

A

patents with renal insufficiency and in those who are at risk for renal insufficiency

18
Q

Long-term efficacy of lamivudine is limited by frequent emergence of drug resistant HBN by a mutation in what

A

CATALYTIC DOMAIN OF HBV POLYMERASE

19
Q

Ribavirin is what analog

A

nucleoSide . . . guanosine analog

20
Q

mechanism of action of Ribavirin

A
  • MONO-phosphate form inhibits IMP dehydrogenase –> decrease GTP
  • TRI-phosphate form inhibits RNA-dependent RNA polymerase –> no RNA replication
  • induces mutation into viral RNA
21
Q

What does Ribavirin do to IFN action

A

potentiates it . .altering the balance between proinflammatory Th1 and Th2 cytokines

22
Q

Explain half life of Ribavirin

A
  • through renal clearance it’s only 1 day
  • BUT .. a lot of it is stored in erythrocytes and 60x concentrated so half life depends on the life span of the erythrocytes . . . . 40 days!!
23
Q

Contraindications for Ribavirin

A
  • hemolytic anemia

- Pregnancy . . even until 6 months post therapy

24
Q

New Direct acting antiviral agents used for HCV infection

A
  • Simeprevir
  • Ledipsavir
  • Sofobuvir
25
Q

Simeprevir inhibits what

A

-protease

26
Q

Ledipsavir inhibits what

A

NS5A

27
Q

Sofosbuvir inhibits what

A

Polymerase

GI 2 (13 decks)

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