mechanism of antiviral drugs Flashcards
what are the main viruses one that’s effects the brain?
HSV
HIV
what are the main viruses that effects the mouth?
HSV
what are the main viruses that effects the liver?
Hepatitis B and C
CMV
3 aims of therapy for anti-virals?
viral eradication = hepatitis C and influenza
long term suppression = HIV and hepatitis B
management of flares/reactiveness of disease = herpesviruses
what are viruses
sub microscopic infectious agents (80-1400 nm)
- they are obligate parasites = this means that they fully rely on the metabolic processes of host cells
how do we classify viruses?
- route of transmission (arbovirus= viruses by insects)
- the disease they cause
- size/shape
- appearance of the capsid
- presence or absence of a lipid environment.
what is the Baltimore classification system?
based on the mechanism of mRNA production
Baltimore classification of system:
what are retroviruses?
what do DNA viruses require?
they are ‘reverse transcribed’ to DNA and integrated to the host genome.
DNA viruses transcription.
Baltimore classification system:
what is the positive sense RNA virus?
what are tiger negative sense RNA virus?
positive = contain RNA in 5’-3’ orientation which can be directly used as mRNA for translation into proteins.
negative= contain RNA in 3’-5’orientation which requires conversion to 5-3’ before translation into proteins.
what is an example of:
I
II
III
I = ds-DNA = adenovirus, Herpes virus
II= ss-DNA = parvoviruses
III = ds-RNA = reoviruses
what is an example of:
IV
V
IV= +ss RNA
V= - ss RNA
WHAT are the 3 main mechanisms of action of anti-viral therapy?
-Virucides
- Anti viral drugs
- immunomodulators
mechanisms of actions of the anti-viral therapy?
virucides= detergents, organic solvents, UV light
Antiviral drugs = inneffective vs non replicating /latent virus
immunomodulators = it will replace the deficient host immune response, enhance the endogeous response (reduces the harmful host immune response)
what stage does the antiviral drugs hat are the 8 stages of viral life cycle?
at which pint does antiviral drugs target?
1) attachment
2) penetration
3) disassembly
4) transcription
5) translation
6) replication
7) assembly
8) release
they can target any of these stage.
what is special about positive ssRNA viruses?
they don’t need to be transcribed - they can undergo direct translation in the host cell cytoplasm.
how do nucleoside analogues work as antiviral drugs?
how is this done?
- these prevent viral replication by interfering with nucleic acid replication, transcription and translation
- this is done using ‘analogue’ compounds which compete with essential nucleotides for binding sites
what is given to treat Herpes Simplex virus DNA replication?
acyclovir
- this will swap guanosine which acyclovir to bind with cytosine on the nucleotide chain.
- this prevents the reading of th viral DNA= can’t transcribe.
what are the 4 considerations for antiviral therapy?
- effectiveness and aim of therapy
- toxicity and side effects
- drug/drug interactions
- emergencies of resistance
what does antiviral drug resistance result from?
- resistance result from mutation within viral genomes
- there is selective drug pressure = resistant viral population
what is the development of resistance favour by?
- development of resiatnce favoured by:
- high viral load
- high intrinsic viral mutation rate
- degree of selective pressure
- resistance barrier of drug class/ individual agent
- antiviral target that can mutate without effecting fitness