Anti-virals Flashcards
Can a virus replicate independently?
No.
Describe the structure of a virus.
- lipoprotein membrane
- Nucleoid: DNA or RNA core
- Surface proteins
- Core proteins (capsid)
What are the 4 main types of anti-viral therapy?
- reverse transcriptase inhibitors
- protease inhibitors
- Absorption and fusion inhibitors
- anti-viral cytokine therapy
What is HIV?
Retrovirus
Mostly infects T4-lymphocytes (express CD4)
Uses cell surface receptors as ports to gain entry in to cell.
What are the 2 main classes of drugs used in anti-viral therapy?
Reverse transriptase inhibitors and protease inhibitors.
What is HAART?
A current therapeutic approach.
‘Highly active anti-retroviral therapy’ - a combo of 3 drugs to prevent resistance.
What are NRTIs? What do they do?
Nucleoside reverse transcriptase inhibitors. (ZIDOVUDINE) = SLOW RESISTANCE
Block conversion of viral RNA -> DNA.
They are prodrugs.
triphosphate metabolite is incorporated into and terminates the DNA chain.
Zidovudine was originally what?
An anti-cancer drug.
What does zidovudine do?
Selective for viral RT but doesn’t effect mammalian DNA pol. It is phosphorylated 3 times and goes into DNA and stops it.
Can cause pancreatitis, liver damage, severe anaemia.
What are NNRTIs?
Non-nucleoside reverse transcriptase inhibitors.
(NEVIRAPINE - lacks selective toxicity)
Useful as part of HAART.
FAST RESISTANCE.
What do protease inhibitors do?
Bind to active site of protease, inhibiting function.
(SAQUINAVIR)
Nausea, vomiting, diarrhoea.
Used in combo.
What is a first fusion inhibitor?
Enfuvirtide.
inhibits entry of HIV into host.
adverse side effects.
What is involved in cytokine therapy?
IFN-a is a naturally occurring glycoprotein secreted by cells due to infection.
Inhibits viral replication in infected cells.
Needs to be administered 3 times a week for chronic hepatitis C.
Major side effects of IFN-a?
Fatigue Depression Flu symptoms Nausea Diarrhoea Appetite loss
