Everyone is different so why treat them the same?
The human genome is made up of 3.5 billion letters which makes you the individual that you are. Although we are very similar (99.9% similarity in genetic code) there are obvious differences between us. This is reflected by our different body sizes, hair colour, tastes etc. It is also shown in different predisposition to developing disease and response to medication. Medication side effects are sometimes predictable, based on knowledge from DNA testing. It is also recognized that 20-30% of medicines do not work in the people to whom they are prescribed. Clopidogrel is a drug prescribed to people with heart disease. When clopidogrel does not work in a person they are considered a nonresponder. Nonresponders are at higher risk of stent thrombosis and death whilst on treatment with clopidogrel. Clinical trials have shown that genetic clopidogrel nonresponders do better when prescribed prasugrel, also known as Effient.
Your medication may not be suited to your genetic makeup
There are many reasons why your medication might not work. In some people forgetting to take their medication regularly may be the most common reason. People lose faith in medicines that may not be working or may be potentially harmful. Generic medicines are often equivalent to branded medicines but sometimes are not absorbed as well as branded medicines. Genetic variation within your DNA code determines how you absorb, metabolise and respond to medication. Clinical studies now indicate that knowing this genetic information can assist in making treatment decisions and improve your health. An example is with the drug clopidogrel also known as Plavix. Plavix does not work in people with a variant in the CYP2C19 gene. In people carrying this CYP2C19 gene variant there is a higher risk of stent thrombosis and death. This may not be the case if people with the CYP2C19 variant are prescribed higher doses of clopidogrel, prasugrel or other more potent antiplatelet medication.
Be tested to ensure you are not at risk of your treatment failing or harming you
A number of cardiovascular and oncology medicines have genetic, DNA tests that act as companion diagnostics, also known as theranostics, and are useful in targeting treatment. The US FDA recommends to doctors that these be considered when prescribing a number of drugs including warfarin, clopidogrel and statins. Knowledge of your genetic makeup can prevent overdose or underdosing with warfarin. With clopidogrel (Plavix) it may potentially prevent stent thrombosis and with statins it can raise awareness to the risk of statin related muscle disease, myopathy. This myopathy, at its worst, can become myositis (inflammation of muscles) and can be extremely debilitating. DNA testing can prevent excessive doses being prescribed and allow you to be aware of your risk for developing this side effect.
Articles
Clinical Applications of pharmacogenetics Cleveland Clinic Journal of Medicine
Cost effectiveness of genetic testing for antiplatelet medication Pharmacoeconomics