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SLCO1B1/simvastatin Pharmacogenomic Lab Test

  • The SLCO1B1 test is used to identify those at risk for side-effects to a medication called simvastatin (Zocor).

  • If your test result shows you have a SLCO1B1 gene variant(s), you are more likely to have severe muscle pain and/or weakness when taking simvastatin. Talk with your healthcare provider about choosing a medication that may be a better option for you.

  • If your test results do not show that you have a SLCO1B1 gene variant, a standard dose of simvastatin will generally be suggested.

SLCO1B1 Test Results

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 SLCO1B1 result mean?

SLCO1B1 (CC) Low Activity

This means you are homozygous for a genetic variant in SLCO1B1. A different medication than simvastatin will likely be prescribed. Talk with your health care provider about choosing a medication that may be a better option for you. For more information, see Medications.

SLCO1B1 (TC) Intermediate Activity

This means you are heterozygous for a genetic variant in SLCO1B1. A different medication than simvastatin will likely be prescribed. Talk with your health care provider about choosing a medication that may be a better option for you. For more information, see Medications.

SLCO1B1 (TT) Normal Activity

Your body processes simvastatin at a normal rate. A standard dose will generally be suggested.

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 SLCO1B1 test result affect my treatment?

If you have an SLCO1B1 variant, your health care provider may adjust your simvastatin dose or suggest you take a different medication.

Who is affected? Do different populations respond differently?

There is no current evidence that different populations respond differently.

Other considerations:

Routine testing for simvastatin and SLCO1B1 are not recommended.

What is simvastatin?

Simvastatin (Zocor) is a medication used to decrease the risk of heart attacks and strokes.

Simvastatin decreases the amount of low-density lipoprotein (LDL) cholesterol (“bad cholesterol”) and triglycerides in your blood. It also increases the amount of high-density lipoprotein (HDL) cholesterol (“good cholesterol”) in the blood.

Which gene affects my response to Simvastatin?

Variants in the SLCO1B1 gene influence the way your body distributes/transports simvastatin and can affect your response to this medication.

What problems can patients with a variant in SLCO1B1 have when taking simvastatin?

Patients who have SLCO1B1 variant(s) are more likely to have severe muscle pain and/or weakness.

Where can I find more information about simvastatin?

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

If you are a healthcare provider and would like more information about pharmacogenomic testing at Mayo Medical Laboratories, call 800-533-1710 (toll-free).