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CYP2D6/codeine Pharmacogenomic Lab Test

  • The CYP2D6 genetic test is used to predict how you will respond to a large number of different medications.

  • Routine testing for codeine and CYP2D6 is usually not done. You may have had the CYP2D6 test done for other reasons.

  • Your CYP2D6 result may have different recommendations based on the specific medications you are prescribed.

  • This website also provides information on the CYP2D6/tramadol and CYP2D6/tamoxifen pharmacogenomic tests.

CYP2D6 test results and codeine

What should I do with my test results?

Talk to your health care provider or pharmacist about the results. They may suggest that you:

  • Keep taking a medication
  • Change the dose of a medication
  • Stop taking a medication
  • Take a different medication

What does my CYP2D6 test result mean?

Poor Metabolizer

Your body processes (metabolizes) codeine poorly to the more active form. Talk with your healthcare provider about choosing a medication that may be a better option for you.

Poor to Intermediate Metabolizer
Intermediate Metabolizer

Your body processes (metabolizes) codeine at a normal rate. A standard dose will generally be suggested.

Intermediate to Extensive Metabolizer
Extensive Metabolizer
Intermediate to Ultra Rapid Metabolizer

There are two possibilities with this test result. Your body may process (metabolize) codeine differently, which may result in side effects. Talk with your health care provider about choosing a medication that may be a better option for you.

Extensive to Ultra Rapid Metabolizer
Ultra Rapid Metabolizer

Your body has an increased ability to process (metabolizes) codeine to the more active form, which may result in side effects. Talk with your healthcare provider about choosing a medication may be a better option for you.

Who will see my results?

Only health care professionals, and those you have given permission, may view your genetic test results. If you are receiving care at another medical facility, we suggest you share this information with your other health care providers.

How could the CYP2D6 test result affect my treatment with codeine?

Your health care provider may suggest you take a different pain medication.

Who is affected? Do different populations respond differently?

Genetic variation in CYP2D6 is dependent on ethnic background. People from Saudi Arabia and Ethiopia are more likely to process codeine quickly, whereas Caucasians are more often found to process codeine slowly.

Other considerations:

Routine testing for codeine and CYP2D6 is not recommended.

You only need to have CYP2D6 genetic testing one time.

What is Codeine?

Codeine is a medication used for pain relief. Sometimes it is used as a cough suppressant.

Which gene affects my response to codeine?

Variants in the CYP2D6 gene influence the way your body processes (metabolizes) codeine and can affect your response to this medication.

What problems can patients with the CYP2D6 variants have when taking codeine?

Patients who have a CYP2D6 variant that metabolizes codeine quickly may experience side effects such as nausea, vomiting, constipation, difficulty urinating, drowsiness, decreased mental alertness and a reduced urge to breathe.

Patients who have a CYP2D6 variant that metabolizes codeine slowly may have poor pain control.

Where can I find more information about codeine?

More information about codeine you might find helpful includes:

These resources may help you understand more about individualized medicine, genomics and drug-gene testing (pharmacogenomics):

If you have questions about your test results, ask to speak with your health care provider at your Mayo Clinic care location:

  • Minnesota 507-284-2511

  • Arizona 480-301-8000

  • Florida 904-953-2000