Session 5 - Anti-virals Flashcards
Outline the lifecycle of influenze
- Influenza virus binds to cell via Hemagglutinin onto sialic acid sugars on the surface of epithelial cells.
- Entry of virus into cell via endocytosis
- ATP driven proton entry into the endosome, allowing fusion of the viral membrane with the internal endosomal membrane
- Entry of protons into the virus itself via the viral M2 Ion Channel. Low pH inside the virus results in breakdown in the viral coat of the nucleocapsid core. This releases viral RNA into the host cytoplasm
- Virus replicates using host cell machinery
- Viral protein assembly
- New virus buds off the cell membrane, but many remain attached by re-attaching to the sialic acid on the cell surface
- Viral Neuramidase enzyme breaks this bond, allowing viral release
What are the three types of influenze?
A, B and C
Where does influenze A reside?
Multiple host species
How does Influenza A change?
Antigenic draft and shift
How is Influenze B different to A?
Lower mortality
What is another name for Influenze C?
Common Cold
What process is target in anti-viral therapy?
- Entry of protons into the virus itself via the viral M2 Ion Channel. Low pH inside the virus results in breakdown in the viral coat of the nucleocapsid core. This releases viral RNA into the host cytoplasm
Name 2 M2 ion channel blockers
Amantadine
Rimantadine
What are the indications of M2 ion channel blocker treatment?
Prophylaxis and treatment of acute Influenza A in groups at risk.
What do M2 ion channel blockers do?
Blocks M2 Ion Channel, preventing breakdown of viral coat and release of viral RNA into host cell.
Which of the two M2 ion channel blockers has more marked ADR
Amantadine more than rimantadine
Give four adverse drug reactions to M2 antivirals
Dizziness
Hypotension
GI disturbance
Confusion, insomnia and hallucination can be problematic in the elderly
What are M2 ion channel blockers effective against?
Group A, not group B
Name two neuramidase inhibitors?
Zanamivir
Oseltamivir
How is zanamivir administered?
Inhaled