• Do Your Medications Actually Work?

    Image for meds Pharmacogenomics or pharmacogenetics is the study of how a person's genes affect how they respond to medicines. It is a relationship doctors have been investigating for years, and only now are they growing closer to being able to tailor drugs and dosages to individual patients.

    What Role Do Genes Play?

    The medicines you take rely on internal mechanisms to metabolize and transport them throughout your body. During this process, thousands of protein molecules interact with them and may alter how well they work. This means that your genes may affect how effectively (or ineffectively) you absorb and metabolize a particular drug, which in turn affects how well the drug works for you.
    Therefore, your genetic make-up could alter your response to drugs used to manage all types of conditions, including depression, pain, blood pressure, and more. It also explains why, in some cases, you may need to try several different medicines to find the one that works for you.
    While medicines may work well for most people, in certain people, a medicine may not work or it may cause annoying side effects. In some cases, these genetic-drug mismatches can prove fatal. Knowing a patient’s genetic code may, therefore, someday help doctors make drug treatments safer.

    How Does This Affect Cancer Drugs?

    Multiple studies have demonstrated the correlation between genes and drug response. The National Institute of General Medical Sciences, a part of the National Institutes of Health (NIH), has funded extensive research in this area. The basic link between genetics and drug efficacy is clear, but more research is needed to reach a practical understanding of how to apply knowledge to everyday care.
    Cancer drugs have been an area of particular interest. This is because in cancer care the need to know whether a drug will or will not work is vitally important, both because these drugs often produce serious side effects and because the time it takes to prove a drug ineffective may allow cancer cells to grow or metastasize.
    One example of the importance of genetics in cancer care is how the thiopurine methyltransferase (TPMT) gene affects the way some people metabolize a certain class of drug used to treat leukemia. Some children who are treated with this class of drug have an alteration in the TPMT gene that causes their bodies to metabolize the drug very slowly. When these children are given the standard dose of medicines in this class, the medicines can build up in their bodies, reaching potentially toxic levels. Other children, however, metabolize this class of drug much more rapidly. These children require larger doses to benefit from the drug. Fortunately, a blood test can determine how long it will take a child to process the drug, and the dose can be adjusted in advance.

    What Does the Future Hold?

    Within the next several years, your doctor may be able to tailor your treatment according to your genetic make-up. Some laboratories offer blood tests to check for gene alterations that vary the effect of cancer drugs. These tests are designed to look for specific changes that may affect the drug about to be ordered. In the future, it may get even easier.
    In the end, the experts offer patients some suggestions for learning more about these issues and technologies:
    • Ask if any information about genes and drugs exists for your condition.
    • Stay aware of new developments.

    RESOURCES

    Human Genome Project Information http://www.ornl.gov/

    National Institute of General Medical Sciences http://www.nigms.nih.gov/

    CANADIAN RESOURCES

    Health Canada http://www.hc-sc.gc.ca/

    Pharmacogenomics Centre http://www.pharmacogenomics.ca/wordpress/

    References

    Anderson JL, Carlquist JF, Horne BD, Muhlestein JB. Cardiovascular pharmacogenomics: current status, future prospects. J Cardiovasc Pharmacol Ther. 2003;8:71-83.

    Bepler G. Pharmacogenomics: A reality or still a promise? Lung Cancer. 2006;54(suppl 2):S3-S7. Epub 2006 Oct 24.

    Evans EE, McLeod HL. Pharmacogenomics—drug disposition, drug targets, and side effects. N Engl J Med. 2003;348:538-549.

    Frequently asked questions about pharmacogenetics. National Institute of General Medical Sciences website. Available at: http://www.nigms.nih.gov/news/facts/pharmacogenetics%5Flaysummary.html. Accessed July 13, 2012.

    Lennard L, Lilleyman JS, Van Loon J, Weinshilboum RM. Genetic variation in response to 6-mercaptopurine for childhood acute lymphoblastic leukemia. Lancet. 1990;336:225-229.

    Mancama D, Kerwin RW. Role of pharmacogenomics in individualising treatment with SSRIs. CNS Drugs. 2003;17:143-151.

    Mancinelli L, Cronin M, Sadee W. Pharmacogenomics: the promise of personalized medicine.AAPS PharmSci. 2000;2: 4.

    Personalized medicines fact sheet. National Institute of General Medical Sciences website. Available at: http://www.nigms.nih.gov/Initiatives/PGRN/Background/FactSheet.htm.Updated August 2011. Accessed July 13, 2012.

    Pharmacogenomics. American Medical Association website. Available at: http://www.ama-assn.org/ama/pub/category/2306.html. Accessed July 13, 2012.

    Pharmacogenomics. US Department of Energy Office of Science, Office of Biological and Environmental Research, Human Genome Program website. Available at: http://www.ornl.gov/sci/techresources/Human%5FGenome/medicine/pharma.shtml. Accessed July 13, 2012.

    Watters JW, McLeod HL. Cancer pharmacogenomics: current and future applications. Biochim Biophys Acta. 2003;1603:99-111.

    Revision Information

  • Join WellZones today.

    Make a Change For LifeLearn more

    Wellmont LiveWell is creating a new tradition of wellness in the mountains by providing individuals with tools and encouragement to live healthier lifestyles.

  • HeartSHAPE Spotlight

    At risk for a heart attack? Learn more

    Fight heart disease early and prevent heart attacks with HeartSHAPE® - a painless, non-invasive test that takes pictures of your heart to scan for early-stage coronary disease.

  • Calories and Energy Needs

    Calorie NeedsLearn more

    How many calories do you need to eat each day to maintain your weight and fuel your physical activity? Enter a few of your stats into this calculator to find out.

  • Ideal Body Weight

    Ideal Body WeightLearn more

    Using body mass index as a reference, this calculator determines your ideal body weight range. All you need to do is enter your height.

  • Body Mass Index

    Body Mass IndexLearn more

    This tool considers your height and weight to assess your weight status.


  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.