Pharmacogenetics Flashcards
what is pharmacogenetics
study of inherited genetic differences in drug metabolic pathways which can affect an individual’s response to drugs (positive or negative)
what effect can changing a protein have on pharmacogenetics of drug
affects absorption, activation, altered traget, catabolism or excretion
what may happen if we get the drug wrong due to different genetics
inactive drug - reduced efficacy to treatment such as in cancer
over active drug - more toxicities introduced
financial cost due to adverse effects
what is TPMT used for and how does it work
chemotherapy
inactivates certain drugs
azathioprine, 6 mercaptopurine and 6 thioguanine - if these are not broken down by TPMT there are cytotoxic compounds
why are polymorphisms of TPMT dangerous
they can’t break down cancer drugs so excess toxic metabolite
what is ivacaftor used for
cystic fibrosis (balletic CFTR mutation) ivacaftor enhances cftr activity which increases the channel permeability this is only seen in patients with G551D genotype
how does succinylcholine relate to pharmacogenetics
it is a muscle relaxant used in anaesthesia but is readily broken down by BCHE activity
you can have rare genotype variants of this protein which prolong the effects of the drug and have a death risk
how can aminoglycosdies cause hearing loss (antibiotics)
G>A mutation at 1555 position in MT-RNR1 gene resembles E coli 16s rRNA so the antibiotics target that at causes hearing loss at a lower age
why does warfarin have varied effects on vit K
due to genetic polymorphisms of VKOR which recycles vit K epoxide
what are the risks of too much or too little warfarin
too much - haemorrhage
too little - patient at risk to underlying condition
how do melanomas and breast cancers vary in treatment rates
20% breast cancers have over expression of HER2 which increase treatment rates of trastuzumab
about 50% melanomas have somatic mutation in BRAF gene which increases treatment efficacy with vemurafenib
