PHARMACOGENOMICS

Your Personalised Pharmacogenetic Profile

 

What is Pharmacogenomics (Pharmacogenetics)?

Pharmacogenomics is the study and the understanding of how genes can affect an individual response to medications.  It combines the field of pharmacology (the science of drugs) and genomics (the study of genes and their function) to develop effective, safe medications that will be tailored to an individual’s genetic make-up and thereby help doctors select the right drugs and dosages that best suits each person.

Genes contain the blue prints (instructions) written in DNA for building protein molecules.  Different people will have different blue prints (i.e. slightly different DNA sequence of the same gene) that will affect health in one way or the other (e.g. genes that are associated with a tendency to develop certain diseases)

Therefore pharmacogenomics researched into genetic variations in genes for proteins that influence the individual genetic response to different drugs. It involves how gens can produce the proteins that are required to carry drugs from the gut into the blood stream and their disposition in the liver, the number of liver enzymes that will convert medications in their active or inactive forms and the breakdown and excretion of drugs by the liver and kidneys.

Knowing whether an individual carries any of these genetic variations can help doctors individualise drug therapy, decrease the chance of adverse drugs events and increase the effectiveness of drugs.

 

What is the expected benefits of pharmacogenomics?

Pharmacogenomics has the potential to provide tailor-made drug therapy based on genetically determined variations in effectiveness and side effects.  This will mean :

  • More powerful medicines – medications more targeted to specific disease, maximizing therapeutic effects and decreasing damage to nearby healthy cells
  • Better, safer drugs – improved recovery and safety with reduction in adverse reactions
  • More accurate methods of determining appropriate drug dosages with refinement and replacement of current dosing based on age and weight to a person’s genetic make-up (i.e. how well the body process the medicine and the time it takes to metabolise them)

 

How is pharmacogenomics affecting the prescribing of drugs in the future?

Currently pharmacogenomic information are already available for more than 150 medications.

The information will cover the effectiveness of such drugs to the individual with certain genomic variations, cover dosage guidance and possible side effects and therefore help doctors tailor their drug prescription for individual patients (personalised medicine). The ability to identify the genetic basis for certain serious side effects allows the doctors to prescribe such drugs only to people who are not at risk for them.

 

Imagine a scenario

You have a heart attack and had a stent deployed in one of your major coronary arteries.  You will require to take an anti-platelet drug (i.e. a kind of mild blood thinner) to prevent aggregation of blood cells that will form to blood clot (thrombus) that will eventually block the stent (stent thrombosis) leading to another heart attack.  Currently the common antiplatelet drugs available are “one size fits all”.  But they may not work the same way for everyone.  The drug may have little effect on preventing the clot from forming on your stent.  It is difficult to predict who will benefit from the medication and who will not respond at all and who will experience negative side effects.  Luckily your doctor sequences your genome to decide if the antiplatelet drug will be effective for you.  It happens that you have a genetic variant indicating that this commonly used drug will have little effect on you.  Armed with this knowledge, your doctor will not be risking you this common antiplatelet drug.  Instead another drug will be provided to you that will prevent the dreaded stent thrombosis.

Simply put, this means using pharmacogenomics testings’ to “get the right doses of the right drug to the right patient at the right time”.

 

How is pharmacogenetics testing done?

  • Two buccal swabs collection are required
  • Your doctor will see you and fill up a request form (with all the necessary information)
  • The sample are collected by rubbing the buccal swabs firmly on the inside of one cheek for at least 45 seconds and then on the other cheek.
  • The swabs are then placed in the sample collection envelop and deliver to the genetic lab for analysis.
  • A personalised pharmacogenetics report will be given in 4 weeks with instructions for use, impact on medications, compilation of genetic review and individual gene review. A physician will also discuss this report with you and advise you accordingly.

 

Once again not all (or everyone) needs to do a pharmacogenetics test as you may currently not require to take any forms of medications.  Moreover every day new genetic information is added to the growing list of drugs tested.