Antivirals (Exam V) Flashcards
What are the unique properties of viruses?
- They are infectious particles (not organisms)
- They are active or inactive (rather than dead or alive)
- They can not replicate outside a host cell (obligate intracellular parasite). They must instruct the genetic and metabolic machinery of the host cell to make and release new viruses.
What are the components to a virus (3)
What is a naked virus?
- Capsid: shell surrounds the nucleic acid
-Nucleocapsid: capsid and nucleic acid together All viruses will have these two things - Envelope- usually a modified piece of the host cell membrane. some virus will have this
- Spikes - Project from either the nucleocapsid or envelope to allow viruses to dock with their host cells
Naked virus consist only of a nucleocapsid
What does the statement “most viruses are self-limiting” mean?
- They are dealt with by the body’s innate immune defense mechanisms and require no antiviral medication.
Which viruses have targeted antiviral therapy?
Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Varicella Zoster Virus (VSV)
Hep C Virus (HCV)
Hep B Virus (HCB)
Influenza
Human Immunodeficiency Virus (HIV)
Respiratory Syncytial Virus (RSV)
Coronavirus (COVID-19)
What type of anti-viral therapy is non-targeted?
Interferon
What is the prototypical, first antiviral drug?
What was it used for?
What is its mechanism of action?
- Acyclovir
- Anti-Herpes for HSV & VZV.
- Inhibition of viral DNA synthesis
What is acyclovir’s mechanism of action?
- Impersonates the deoxyribose sugar of a DNA chain. Missing a hydroxyl group so the chain ends up terminating.
When is acyclovir indicated?
Does this change for pregnancy?
- HSV 1 & 2, and Varicella Zoster Virus infections.
- Beneficial in pregnant women, ↓ viral shedding and ↓ c-section rate.
Which antiviral is a inhibitor of reverse transcriptase, treatment for HIV?
What is the therapy called when this drug is combined with others to treat HIV?
- Azidothymidine (AZT) Zidovudine, reverses transcriptase.
- Highly Active Antiretroviral Therapy (HAART), cocktail with a combination of 6 different drugs
What is the MOA of Lamivudine?
What is the MOA of Tebivudine?
When would you use Tenofivir?
Lamivudine:
Inhibits HBV DNA polymerase and HIV reverse transcriptase.
Tebivudine:
Inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate, thymidine 5’-triphosphate.
Tenofivir:
- Activity against HIV & HBV
- Effective in treating Lamivudine-resistant HBV
How do Lamivudine & Telbivudine work?
- Inhibition of HBV DNA polymerase
- Inhibition of HIV reverse transcriptase
What are the antiviral drugs recommended by the CDC for the flu?
- Oseltamivir (Tamiflu) - take within first 48hrs
- Zanamivir (Relenza) - target neuramindase protein
- Baloxivir Marboxil (Xofluza)- one time dose
Which influenza antiviral is a one-time dose pill?
Who cannot receive this medication?
- Xofluza (Baloxivir Marboxil)
- Pregnant and/or breastfeeding mothers, & hospitalized or very ill patients
What human cell surface antigens are used to categorize influenza subtypes?
- Hemaglutinin (H1, H2, H3)
- Neuramindase (N1, N2)
What role does human hemaglutinin have in influenza infection?
- Viral attachment to human cells
