502 Final Quizlet Flashcards
(171 cards)
List the different types of viral hepatitis.
A, B, C, D, E
What type of virus causes Hep A?
RNA Virus
Is there a vaccine to prevent Hep A?
Yes
Is Hep A usually acute or chronic?
Acute condition that will resolve (never chronic)
How is Hep A transmitted?
Fecal into oral route
What type of virus causes Hep B?
Partially double-stranded small nonenveloped DNA virus
How is Hep B transmitted?
Blood and infected fluids
Is Hep B acute or chronic?
Chronic
Is there a vaccine to prevent Hep B?
Yes
What type of treatments are available for Hep B? What is the efficacy of these treatments?
Immune modulators and antivirals. These usually don’t completely eliminate the virus.
What is the mechanism of action of Lamivudine?
Cytosine analogue that acts as a reverse transcription inhibitor. (Inhibits DNA polymerase)
What is the MOA of Adefovir and Tenofovir? How are these activated from the prodrug form?
Adenosine analogue that acts as a reverse transcription inhibitor (inhibits DNA polymerase). Activated by adenylate kinase, which adds a second phosphate group.
What is the MOA of Telbivudine?
It converted to the active form With the addition of what chemical group? Thymidine nucleoside analog that inhibits DNA polymerase and causes chain termination of DNA synthesis. Addition of three phosphate groups.
What type of virus causes Hep C?
Positive-sense single-stranded RNA virus
How is Hep C transmitted?
Blood
Is there a vaccine to prevent Hep C?
No
Is Hep C primarily chronic or acute?
Can be either, but 80% progress to chronic.
What is the goal of treatment for Hep C and how is it measured?
Goal is to cure. This is measured with sustained virologist response, which is the absence of detectable HCV RNA in the plasma for 12 weeks following therapy.
What is the general MOA of the serine protease inhibitors?
Inhibit the actions of the NS3/4A serine protease, which is required to cleave the HCV RNA genome to form proteins used for viral replication. NS3/4A is a non-covalent heterodimer complex, where NS3 has the serine protease catalytic domain and NS4A has an activation subunit domain.
What is the general MOA of the NS5B polymerase inhibitors?
They inhibit the action of RNA polymerase which is needed for viral replication. Some act as nucleotide analog substrates while some bind to almost Eric sites on the enzyme and render it non-functional.
Which drug acts as a uridine nucleotide analog?
Sofosbuvir
How is Sofosbuvir activated? What is the rate limiting step?
It activated during first pass metabolism by hepatic kinases. The rate limiting step is addition of the first phosphate group. Active form is triphosphorylated.
Which drug acts as a non-nucleoside inhibitor at the allots Eric site on polymerase-palm 1?
Dasabuvir
What is the general MOA of NS5A inhibitors?
Inhibit NS5A proteins, which are required for viral replication.