29 Jan Pharmacogenomics and individual medicine.
We are all born different, our genetic material, genotype, determines many of our traits and characteristics, including our response to drugs and chemical substances.
Although many factors such as age, organ and body conditions have an impact, it is estimated that up to 95% of the variability in drug response is inherited.
Variations in drug response are of great clinical importance.
Certain doses of the drug can be effective for someone, the same dose less effective for someone else, and it is not uncommon for them to be completely ineffective or even harmful.
This brings us to the field of pharmacogenomics.
Pharmacogenomics deals with the study of genetic causes of variations in response to drugs, with the aim of optimizing therapy for individual responses.
In simpler terms, it looks for a connection between our genes and the effectiveness of available therapies, and thus enables doctors to prescribe adequate drugs and doses.
This can have multiple benefits.
It may allow us to reduce side effects.
By understanding how one’s genetic material affects the response to a certain drug, we can determine the appropriate therapy in advance by simply conducting genetic tests.
It can also lead to increased efficiency.
By knowing in advance which drugs will be most beneficial, we save time and money that would be spent on the wrong therapies, not to mention potential health complications.
All this leads to improved outcomes of treatments.
When we know which medicine someone will respond to best and in what doses, it is easy to achieve the maximum effect.
There is every possibility that pharmacogenomics will lead to a revolution in the field of medicine by moving it towards a significantly more individualized approach.
Also, the more we understand the genetic basis of responses to chemical substances, the more we will be able to produce more effective drugs.
In what ways has pharmacogenomics contributed to medicine so far?
Genetic testing for response to some of the drugs for hypertension, epilepsy, depression, and anticoagulation has already become standard practice before prescribing therapy.
It has become especially important in oncology patients, where the drugs themselves can be quite harmful to an organism that is already weakened by the fight against the disease, so that therapy with the best effect and minimal side effects is very often crucial.
One of the drugs that has been studied in detail is warfarin, an anticoagulant prescribed to patients with atrial fibrillation. It has been shown to reduce the risk of stroke by increasing blood clotting time.
The most important genes that determine the body’s response to this drug are CYP2C9, CYP4F2 and VKORC1.
| Gene | Variation | Clinical impact |
| CYP2C9 | 430 C>T (*2) 1075 A>C (*3) | 17% smaller dosage 37% smaller dosage |
| CYP4F2 | 1347 C>T | Almost double dosage is needed |
| VCORC1 | -1639 G>A | Lower dosage |
This and many other examples in practice already prove the need for further development of pharmacogenomics.
