Personalised medicine Flashcards
What does PM aim to do?
Customize healthcare with decisions and treatments tailored to each individual patient
What are the benefits of PM?
Reduce trial and error processing avoid adverse reactions increase patient compliance reveal additional uses control costs of healthcare
Examples of tailored approaches?
Warfarin- genotype can be used to prescribe the right dose
FH-homozygous/heterozygous effects how they respond to treatment
Heart transplant patients- instead of biopsy- allomap test
How does plavix/clopidogrel effect people differently?
People can have certain genetic factors which affects how the body breaks down plavix
cyp2c19- metabolises clopidogrel to its active form
depending on your levels and genetic polymorphisms- some people can have reduced levels of the enzyme
What is an example of pharmacokinetics?
drug concentration can change over time in different regions- depending on how the drug was absorbed
How are individual responses to drugs adjusted?
by monitoring physiological endpoints- function of platelets etc
How does age affect drug actions?
drug elimination less efficient in new borns and old people
new borns= organs not well developed, drug metabolizing enzymes are altered
body composition changes with age
digoxin- increases strength and efficiency of contraction of the heart- half life in neonates= 200 hrs
half life in adults= 40 hrs
have to adjust dose accordingly
Examples of how ethnicity effects drug actions
Chinese people- altered metabolism of alcohol
african americans- respond very well to hydralazene (heart failure drug) when used with a nitrate- very effective compared to white people
Whats a polymorphism?
an alternative sequence at a specific loci within the DNA strand
SNPS are very common
C-T most common
Example of a disease implicated by polymorphisms?
Inherited thrombophilia/ factor 5 leiden disease
caused by a single SNP in the clotting factor 5 leiden
increases the risk of clotting
high risk of having DVT
How can concomitant disease affect drug actions?
kidney/liver disease- can cause prolonged/ intense drug effects
other conditions can cause gastric stasis- alters the way drugs behave
Example of a drug-chemical interaction
Simvastatin and grapefruit juice
Examples of pharmacodynamic interactions we know about
Diuretics (used in heart failure) lower plasma potassium and predispose to digoxin toxicity
Sildenafil (used in pulmonary hypertension- is a vasodilator) potentiates organic nitrates- big combination effect- low blood pressure- can collapse
Where are polymorphisms tested for in warfarin genetic tests and why?
CYP2C9- encodes the enzyme which breaks warfarin down- people can be slow/normal/fast metabolisers
VKORC- encodes the drug target of warfarin- people who have a G to A transition in the promoter are more sensitive to warfarin- need a lower dose
