Pharmacogenomics Flashcards
What is pharmacogenomics?
The study of genomic influence on drug response, often through complex interactions.
What is pharmacokinetics?
The fate of the drug in the body.
What is pharmacodynamics?
The effects of drugs in the body.
What is pharmacogenetics?
The study of individual gene-drug interactions, simple relationships of one or two genes effect on drug response.
What is haemolytic anaemia?
Red blood cell destruction, triggered by:
Infections, stress, fava beans, and medications - antimalarials, sulphonamides, aspirin.
What is G6PD deficiency?
Highest frequency in malaria infested regions.
This gives a survival advantage against malaria.
Deficiency seen more in men than women.
X-linked characteristic.
What is suxamethonium chloride?
Nicotinic acetylcholine receptor agonist, binds non-competitively at the synaptic junction.
This means it is not reversed by other drugs, and will wear off very slowly.
It is a fast acting depolarising muscle relaxant, can be used in anaesthesia.
Mostly metabolised by non-specific plasma cholinesterase.
What is suxamethonium apnoea?
Occurs when a patient has been given suxamethonium chloride muscle relaxant before surgery.
Patient cannot metabolise drug sufficiently rapidly, so remains paralysed and unable to breathe after the surgery.
Related to genetic variations of BCHE.
What is CYP2D6?
Cytochrome P450 2D6 metabolises many drugs.
It is a non-inducible enzyme - cannot change its expression through drugs.
Bimodal pattern - some patients have difficulty metabolising drugs that this enzyme normally would - debrisoquine or sparteine.
What are the classes of metabolisers?
Ultrarapid metabolisers
Extensive metabolisers - normal metabolisers.
Intermediate metabolisers
Poor metabolisers - these two have reduced function
Status depends on highest functioning allele of CYP2D6.
What do intermediate and poor metabolisers do?
They are not able to metabolise CYP2D6 substrates.
This means there are higher plasma levels of the parent drug, so increased risk for adverse effects.
Inability to form an active metabolite - lack of efficacy.
What is genetic variation in enzymes?
Variation in the enzyme activity caused by mutations leads to altered breakdown and excretion of many drugs.
