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Pharmacogenetics: one step away from the before and after of medicine


Pharmacogenetics is taking on special importance recently, as it is considered one of the pillars of personalized medicine.

Surely you have heard of it, haven’t you? It is a theque still has a long way to go, but it has been seen that it can mark a before and after in medicine.

Several clinical studies have shown that having a pharmacogenetic test is extremely important to know which drug and what dose should be administered to each patient. In this way, possible adverse reactions to said treatment are avoided and/or reduced, apart from projecting a favorable clinical outcome, improving the person’s quality of life. In fact, even for some treatments, it is compulsory to perform this study before starting the corresponding therapy.

In case the patient needs a treatment with several drugs at the same time, a drug compatibility study can be performed to know the interactions between these drugs in the patient’s body. Esto le permitirá elegir la combinación más apropiada.

In addition, being personalized depending on the patient’s genetics and state of health, the recovery time will decrease completely, thus increasing the cost-effectiveness of the treatments, optimizing the available health resources and limiting problems derived from ineffective treatments, such as antibiotic resistance.

What is analyzed in a pharmacogenetic study?

In DNA there are variations in the genetic sequence. So-called polymorphisms occur in at least 1% of the population and promote normal population diversity. These variations can modify the expression and function of enzymes, transporters or therapeutic targets involved in pharmacodynamics and pharmacokinetics.

For example, variations in genes involved in drug metabolism in the liver can alter the efficacy and/or safety of drugs, or polymorphisms in genes coding for transporters in the blood-brain barrier can determine their activity in the central nervous system.

farmacogenetics test

A pharmacogenetic test, as mentioned above, involves the analysis of genetic markers that determine the behavior of the drug through the organism, which will be evaluated by pharmacokinetics, and on the other hand of polymorphisms that modulate the response of the organism to the drug, which are dealt with by pharmacodynamics.

The most widely studied aspect in the field of pharmacokinetics is drug metabolism.

The set of polymorphisms in each individual will define his or her capacity for drug transformation, and both increasing and decreasing his or her metabolic capacity could work for or against the success of the therapy. Thus, the most common types of metabolization are:

  • Normal or Extensive Metabolizer (EM): they do not present variations in the rate of metabolism, nor in therapeutic efficacy or toxicity with respect to that previously established.
  • Poor Metabolizer (PM): implies less degradation of the drug, and thus more time in the body and greater probability of adverse effects, but also a prolonged therapeutic effect. In addition, for drugs that require a first activation step, poor metabolism would mean less active drug available or a delayed therapeutic effect.
  • Intermediate Metabolizer (IM): the consequences are similar to those of poor metabolism, but to a lesser degree. It would present a slightly increased risk of developing adverse reactions, and would imply a lower efficacy than that established for that drug.
  • Ultra-rapid metabolizer (UM): greater degradation of the drug, reducing the time it remains in the body, so that both adverse effects and effectiveness will be reduced. For drugs that require prior activation, the therapeutic effect will probably be observed earlier.

Pharmacodynamics studies the relationship between the drug reaching the target site and the effects triggered. The main therapeutic targets are usually receptors, ion channels or enzymes. Additionally, it can be affected by physiological changes, health conditions or administration of other drugs or food.

Depending on the results of each DNA test, the procedure to be followed by the physician will consist of using the established standard doses, decreasing or increasing the doses as needed, or using other alternative treatments.

This information is based on studies carried out by the FDA (Food and Drugs Administration), the EMA (European Medicines Agency) and other prestigious pharmacogenetics institutions, such as the CPIC (Clinical Pharmacogenetics Implementation Consortium) or the DPWG (Dutch Pharmacogenetics Working Group).

It is important to emphasize that the results given in the tellmeGen reports are recommendations. In no case should the patient change his or her pharmacological treatment without review and approval by his or her physician.

I want my pharmacogenetic study, what should I do?

The DNA tests available at tellmeGen allow you to know the response to various drugs and more than 150 pharmacological compatibilities based on your genetics, avoiding complications in the clinical process, favoring your recovery.

Here is an example of the results provided by the DNA test at tellmeGen.