Iowa Institute of Human Genetics

  • CYP2C19 Genetic Screen for People Taking Clopidogrel (Plavix®)

    What is clopidogrel (Plavix®)?

    • Clopidogrel (Plavix®) is a medicine used to thin your blood to prevent blood clots
    • People with heart disease take clopidogrel to prevent heart attack and stroke

    What are genes?

    • Genes are short pieces of DNA that contain information about our bodies
    • Genes are passed down to us from our parents before we are born
    • Genes have DNA changes (variants) in them that determine a great deal about us, including what we look like and how our bodies react to medicine

    What is a genetic screen?

    • It is used to show the gene changes in a person

    Why would I have a genetic screen for clopidogrel (Plavix®)?

    • Your body may process clopidogrel normally, very fast, or poorly
    • The CYP2C19 gene controls how your body will process (metabolize) clopidogrel
    • The type of CYP2C19 gene you have will help your doctor decide if clopidogrel will work for you
    • Learning about your CYP2C19 gene can help your doctor choose the right medicine and dose for you

    How do variants in this gene affect me?

    • If your CYP2C19 gene is the type that processes clopidogrel poorly, the drug will not work well for you

    What do I need to do for a genetic screen?

    • You will be given a small sponge to wipe across the inside of your cheek to collect a sample of your DNA (genes)
    • The sample will be used to study your CYP2C19 gene
    • You also may be asked for a saliva or blood in case the sponge does not work

    How will I learn about my results?

    • Your doctor or nurse can tell you the results at your next appointment
    • The results also will be in your MyChart account

    Are there any limitations to this screen?

    • This screen only looks at the four most common variants of CYP2C19
    • Other variants in CYP2C19 will not be found, but they can affect how your body will process clopidogrel
    • Please let your doctor or nurse know if you are taking other medicines

    What other medications are affected by CYP2C19?

    CYP2C19 variants also affect how other drugs work including: 

    • Proton Pump Inhibitors (PPIs) for acid reflux. Talk with your doctor if you are taking PPIs like Nexium®, Prilosec®, Prevacid®, or Protonix®.
    • Anti-depressants. Talk with your doctor if you are taking SSRIs or tricyclic antidepressants such as Celexa®, Lexapro®, or Zoloft®.

    Can my insurance get my genetic screen results?

    • Yes, your insurance company can get the results of this screen from your medical records
    • We have a genetic counselor who can answer your questions about insurance companies and genetic information

    Helpful Websites

    The Pharmacogenomics Knowledgebase provides information about how genes interact with medicines.

    Genetics Home Reference provides information about how genes affect your health: what genes are, how they work and how they can cause illness.

    Iowa Institute of Human Genetics provides information for patients, health care providers, researchers, and students