subject: The Truth About Pharmacogenetics [print this page] Pharmacogenetics, or the scientific study of genetic variations in relation to their response to medicines, is not supposedly new. The term had already been coined in 1959 by a German scientist, Friedrich Vogel. But by then, the knowledge and resources of gaining more knowledge about the subject were extremely limited. It was not until the completion of US-funded the Human Genome Project that scientists become interested again in delving into this investigation again.
The fundamental principle of pharmacogenetics is to personalize medicines based on an individual's genetic composition. Many of the findings of this study are founded on the insights of biochemical pathways within the human cells. For instance, medical scientists already have knowledge on the enzymes that break down the irinotecan-a certain anti-cancer anti-biotic-when its harmful effects in some patients are clear.
Such knowledge enables the researchers to accurately identify a genetic variant among these enzymes as the primary cause of the harmful reaction. This technique is accomplished through a genetic test, which can determine the genetic variant so physicians can make adjustments on the dosage of irinotecan for those who are at risk for serious adverse reactions.
The advances in this scientific study can also arise from the research studies that come with clinical drug trials. With the participants' consent, certain pharmaceutical organizations accumulate DNA samples from the participants of drug trials. The pharmaceutical scientists will then analyze these samples along with the results from the clinical trials to pinpoint the genetic variations that associate with a drug's efficacy or toxicity.
Researchers involved in the study between the gene's responses to certain drugs have already catalogued many genes whose variations influence the drug responses. Also, they already know the areas to look for to discover other gene variations. This was made possible after the completion of the Human Genome Project in 2003, which paved the way for the HapMap project as well. The HapMap project is an international collaboration to identify and catalog common genetic variations among human beings. The knowledge in pharmacogenetics can be used by physicians to determine the optimal dose for every patient.
The Right Dosage. Before the doctor prescribe the dosage, he takes into consideration such as the patient's age, weight, and kidney and liver function. However, for a person whose genetic makeup makes his body break down the drug quickly, a regular dose may prove ineffective. On the other hand, a person whose genetic makeup allows his body to break down the drug slowly may need a lower dosage to prevent the accumulation of toxic levels of the drug in his bloodstream. Having a pharmacogenetic test can be helpful in discovering the right dosage for every patient.
The Right Drug. Many researchers use the knowledge in the emerging science in certain targeted therapy for cancer to ascertain the best drug formula for a specific tumor. Even tumors of similar type-such as liver, breast and lung-differ at the genetic level. Fundamentally, cancer is a genetic disease. However, most of the genetic variations between cancer cells and normal cells are accumulated as the cancer progresses. Being able to analyze particular genes in a patient's tumor is helpful in identifying the drug combination to which the tumor will likely respond-in a positive way.
