Antivirals Flashcards
Are viruses alive or dead?
What are they?
Neither (can be active or inactive)
Obligate intracellular parasites
What two components do all viruses have?
Capsid (external coating)
Core of nucleic acids
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.
What are the two overarching categories of viruses?
DNA Viruses
RNA Viruses
What sub-category of RNA viruses is unique? How are they different from other viruses?
Retroviruses
Reverse Transcriptase mechanism (RNA → DNA vs DNA → RNA → proteins)
What type of anti-viral therapy is non-targeted?
Interferon
What is a viral capsid?
How would a nucleocapsid differ from this?
Shell surrounding nucleic acids
Nucleocapsids are capsid & nucleic acid together.
What is a viral envelope usually composed of?
Modified piece of a host cell membrane
Naked viruses consist only of a ____________.
nucleocapsid
What component of a virus allows “docking” on host cells?
spikes
How does a virion differ from a virus?
Virion = Fully formed virus able to establish infection in a host cell.
Virus = No metabolic activity yet (needs to infect something)
Virus families are denoted with the suffix _______.
-viridae (herpesviridae)
Virus genera are denoted with the suffix ______
-virus (simplexvirus)
What is the viral family of the influenza viruses?
Orthomyoxviridae
What is the viral family of HIV?
What about the genus?
Retroviridae
Lentivirus
What genuses are in the Herpesviridae family?
Simplexvirus (Herpes Simplex 1 & 2)
Varicellovirus (Varicella Zoster = chickenpox)
What is the viral family of the Hepatitis viruses?
What about the genus?
Hepadnaviridae
Hepadnavirus
What are the five phases of viral replication?
Adsorption
Penetration
Synthesis
Maturation
Release
What is the process of viral adsorption?
Attachment of virus to host cell via spike protein
What is the process of viral penetration?
What is it called if the entire virus enters the cell?
Entry of virions (or genome) into host cell
Uncoating
What is the process of viral synthesis?
Creation of new nucleic acids, capsid proteins, & other viral components.
What is the process of viral maturation?
Assembly of newly created viral components into complete virions.
What is the process of viral release?
Release of new virions from host cells.
What two types of viral release exist? Differentiate the two.
Lytic → rupture of host cells, fast & self-limiting (think GI virus)
Lysogenic → Slow release, makes host cell become viral factory. Can become lytic eventually.
What is the prototypical, first antiviral drug?
What is its mechanism of action?
Acyclovir
Inhibition of viral DNA synthesis
What is the indication for Acyclovir?
HSV & VZV
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 VZV infections.
Beneficial in pregnant women, ↓ viral shedding and ↓ c-section rate
What viral component allows HIV to bind to CD4⁺ T-lymphocytes?
gp120 spike protein
Which antiviral is a inhibitor of reverse transcriptase?
What is the therapy called when this drug is combined with others to treat HIV?
Azidothymidine (AZT) Zidovudine
Highly Active Antiretroviral Therapy (HAART)
Which drugs have activity against both HBV and HIV?
Lamivudine
When would one use Tenofivir?
HIV & HBV
Lamivudine-resistant HBV
How do Lamivudine & Telbivudine work?
Inhibition of HBV DNA polymerase
Inhibition of HIV reverse transcriptase
Interferon can be used for ____________ but it’s better at treating _______ ________.
viruses ; autoimmune diseases
What antivirals are available to treat influenza?
Oseltamivir (Tamiflu)
Zanamivir (Relenza)
Baloxivir Marboxil (Xofluza)
When must tamiflu be give to be successful?
How much efficacy do antiviral influenza drugs have?
48hrs
Usually shorten course of illness by 1 day.
Who should not be given Relenza (Zanamivir) for their influenza infection?
Why?
Patients with asthma & COPD
Relenza is an inhaled medication
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 influenza infection?
Viral attachment to human cells
What role do human neuraminidases have in influenza infection?
Cell Penetration
Between Flu A & Flu B, which is generally more severe?
Influenza A.
Which Influenza subtype has less antigenic shift and is generally more mild?
Who is generally more affected?
Does this flu infect anything other than humans?
Influenza B
Children
Seals
What is the progression of a COVID infection?
Attachment to ACE receptors → inflammatory mediators → WBCs → Cytokine Storm.
What severe outcomes can occur with cytokine storm?
ARDS
Multi-Organ Failure
Hyperinflammation syndrome
Death
What gene may be responsible for an increased susceptibility to COVID infection/severity?
Alu Polymorphism in ACE receptors
What PO drug has been approved for COVID infection?
Paxlovid
What parenteral drugs have been approved for COVID? Give their MOAs.
Remdesevir - chain termination inhibiting new viral synthesis.
MABs - block COVID entry into cells
Dexamethason
used to treat COVID-19
Aids with cytokines
Cabotegravir
HIV Pre exposure prophylaxis
