What is pharmacogenomics?
Pharmacogenomics is the study of genetic variations that influence individual response to drugs. Knowing whether a patient carries any of these genetic variations can help prescribers individualize drug therapy, decrease the chance for adverse drug events, and increase the effectiveness of drugs.
Pharmacogenomics combines traditional pharmaceutical sciences such as biochemistry with with an understanding of common DNA variations in the human genome. The most common variations in the human genome are called single nucleotide polymorphisms (SNPs). There is estimated to be approximately 11 million SNPs in the human population, with an average of one every 1,300 base pairs. An individual's response to a drug is often linked to these common DNA variations. In a similar manner, susceptibility to certain diseases is also influenced by common DNA variations. Currently, much of the research in the field of pharmacogenomics is focused on genes encoding either metabolic enzymes that can alter a drug's activity or defective structural proteins that result in increased susceptibility to disease.
Anticipated benefits of pharmacogenomics
Pharmacogenomics has the potential to provide tailored drug therapy based on genetically determined variation in effectiveness and side effects. This will mean:
- More powerful medicines - Pharmaceutical companies will be able to produce therapies more targeted to specific diseases, maximizing therapeutic effects while decreasing damage to nearby healthy cells.
- Better, safer drugs the first time - Recovery time will go down and safety will go up as the likelihood of adverse reactions goes down or is eliminated altogether.
- More accurate methods of determining appropriate drug dosages - Current methods of basing dosages on weight and age will be replaced with dosages based on a person's genetics --how well the body processes the medicine and the time it takes to metabolize it.
Practical applications of pharmacogenomics today
Following are links to scientific abstracts that discuss practical applications of pharmacogenomics in cancer, depression, cardiovascular disease and drug metabolism:
- Cancer pharmacogenomics: current and future applications
Watters JW, McLeod HL
Biochim Biophys Acta 2003 Mar 17;1603(2):99-111
- Pharmacogenomics study of statin therapy and cholesterol reduction
Chasman DI, et al.
JAMA 2004; 291(23) 2821-2827.
- Role of pharmacogenomics in individualizing treatment with SSRIs
Mancama D, Kerwin RW
CNS Drugs 2003;17(3):143-51
- Cardiovascular pharmacogenomics: current status, future prospects
Anderson JL, Carlquist JF, Horne BD, Muhlestein JB
J Cardiovasc Pharmacol Ther 2003;8(1):71-83
- Pharmacogenomics — Drug disposition, drug targets, and side effects
Evans, WE, and McLeod, HL
NEJM 2003; 348:538-549
Economic issues from molecule to marketplace
Pharmacogenomics eventually can lead to an overall decrease in the cost of health care because of decreases in:
- the number of adverse drug reactions,
- the number of failed drug trials,
- the time it takes to get a drug approved,
- the length of time patients are on medication,
- the number of medications patients must take to find an effective therapy, and
- the effects of a disease on the body (through early detection).
National Institute of Pharmaceutical Education and Research