Genetic Testing Pharmacogenetic

Did you know that by using the new science of pharmacogenetic testing, doctors may soon be able to personalize a dose of medicine just for you?

Pharmacogenetics is the study or clinical testing of individual genetic variations which gives rise to differing responses to drugs. While not widely used now, researchers hope it will eventually influence the safety and efficiency of prescribed medicines.

How Pharmacogenetic Testing Works

Pharmacogenetic tests identify variations in a person’s genetic makeup in order to predict their responses to a medicine. The results may indicate how a patient will respond to a particular medicine, and possibly the side effects they will experience. It may also yield recommendations on dosage.

The test is done by analyzing a person’s DNA. Researchers administering the test look for the presence or absence of a particular gene, and any changes it may have undergone. Pharmacogenetic tests can be performed on blood samples, cheek swabs, or, as with some cancers, on biopsy tissue.

Genetic Variation Influences Drug Efficiency

It is common knowledge that not everyone has an identical response to the same drug. Even two people who have the same body weight will respond differently. A person’s genetic makeup is what determines how they will respond to certain drugs.

Definition of Genetic Variation

Human genetic variation is the natural variation in gene frequencies observed between the genomes of individuals or groups of humans. Variation can be measured at both the individual level (differences between individual people) and at the population level, i.e. differences between populations living in different regions.

In other words, as much as we’re all the same, our genetic makeup does exhibit distinct differences. So, pharmacogenetic researchers and supporters say, it makes sense that we should all be medicated differently.

Benefits to Pharmacogenetic Testing

Both patients and doctors benefit from pharmacogenetic testing. On its most basic level, the doctor-patient relationship is about relieving pain. You are broken, the doctor wants to fix you, and drugs may be the tool used. But what if those tools don’t work? What if a lower or higher dose is required, or a new drug entirely?

Pharmacogenetics may be able to find that out and help the physician offer relief.

Benefits of pharmacogenetic testing for physicians include:

  • Maximizing treatment success: Physicians will be able to individualize treatments to match patients’ genetic makeup.
  • Minimizing liability: Eliminating trial and error obviously lessens the chances for mis-diagnoses.
  • Keeping Current: Knowledge is power. An understanding of basic genetics is another tool in a doctor’s arsenal.

Benefits of pharmacogenetic testing for patients include:

  • Provides personalized and clinically relevant drug-drug and/or drug-gene interaction information.
  • Reduces side effects: Outside oncology, the test’s widest use is to identify patients who are at risk of side effects from particular medicines
  • Provides more efficient relief: Finding out before treatment what may not work for you improves the efficacy of care.

Metabolizing Drugs

Drugs are metabolized by enzymes, which modify and break down the drug and lead to our reaction. While everyone metabolizes drugs, we don’t all do it the same way or at the same rate.

This is where pharmacogenetic testing comes in. Sometimes the tests show that a drug doesn’t work. For example, the pain reliever codeine cannot be broken down by seven percent of whites and two percent of blacks. These people get the side effects and none of the pain relief.

Pharmacogenomic Testing

Pharmacogenomics is often used interchangeably with pharmacogenetics. There is a small difference.

While pharmacogenetics is the study of inherited genetic variations in drug metabolism and response, pharmacogenomics is the general study of all of the many different genes that determine drug behavior. That one subtle difference aside, both sciences are committed to reducing adverse drug reactions and eradicating the idea of “one size fits all” dosing.

Resources

Genele (n.d.). Pharmacogenetic Testing. Retrieved September 16, 2008, from the Genele Web site: http://www.healthanddna.com/healthcare-professional/pharmacogenetics.html#cat.

NCBI (n.d.). One size does not fit all: the promise of pharmacogenomics. Retrieved September 16, 2008, from the NCBI Web site: http://www.ncbi.nlm.nih.gov/About/primer/pharm.html.

The Royal Society (n.d.). What is pharmacogenetics? Retrieved September 16, 2008, from The Royal Society Web site: http://royalsociety.org/page.asp?tip=1