The right drug at the right dose at the right time

This section provides information only about this specific pharmacogenomic test.


  • If you have medication questions, ask your health care provider.
  • Follow your health care provider's instructions when taking any medication.
  • Do not change your medications without talking with your health care provider.

CYP2D6/Venlafaxine Pharmacogenomic Lab Test

Key Facts

  • CYP2D6 testing is used to determine potential risk for side effects to some antidepressant medication like venlafaxine (Effexor®)
  • Routine CYP2D6 testing for venlafaxine (Effexor®) is usually not done at this time. Your health care provider will decide if this test is appropriate for you
  • Your health care provider evaluates your test results and uses this information, along with your other health information, to make recommendations for appropriate treatment options
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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 result mean?

Poor or poor to intermediate

Consider an alternative due to an increased risk of drug effects.

Who will see my results?

Only health care professionals, and those individuals to whom you have given permission, see your genetic test results. If you are receiving care at another medical facility, Mayo Clinic recommends you share this information with your other health care providers.

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

If you have a CYP2D6 gene variant, your health care provider may suggest you take a different medication or adjust the dose of the medication.

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What is venlafaxine?

Venlafaxine (Effexor®) is an antidepressant. Venlafaxine is used in individuals suffering from depression, general anxiety, panic disorder, social anxiety disorder etc.

Which gene affects my response to venlafaxine?

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

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

Patients who have a CYP2D6 gene variant process (metabolize) venlafaxine differently than patients without the gene variant. Talk with your health care provider about other medications that may be a better option for you.

Poor metabolism and poor to intermediate metabolism of this drug by CYP2D6 has been associated with the potential for reduced drug effect.

Where can I find more information about venlafaxine?

More information about venlafaxine you might find helpful includes:

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

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

  • Minnesota
  • Arizona
  • Florida
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