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Sympathetic Nerve Block

Medically reviewed by Last updated on Jan 5, 2023.


What you need to know about a sympathetic nerve block:

A sympathetic nerve block is an injection of anesthesia medicine around nerves near your spine. You may need a sympathetic nerve block to locate an area of pain or to relieve nerve pain. It may be used to help your healthcare provider guide your treatment. You may need a series of injections if your pain or condition improves after the first. If you have a clotting disorder, you may not be able to receive a nerve block.

How to prepare for a sympathetic nerve block:

Tell your healthcare provider if you or anyone in your family has ever had problems with anesthesia. You may need to arrange to have someone drive you home after you have the nerve block. Your healthcare provider will talk to you about how to prepare. You may be told not to eat or drink anything after midnight on the day of your nerve block. Tell your provider about all medicines you are taking, including vitamins and herbs. Your provider will tell you which medicines to take or not take on the day of your nerve block. You may need to stop taking certain medicines several days before your nerve block.

What will happen during a sympathetic nerve block:

Your healthcare provider will ask you to rate your symptoms before the procedure. You will remain awake and alert during the procedure so that you can answer questions. Your provider will find the area of the nerve group to be treated. Fluoroscopy (an x-ray that produces moving images), CT scans, or an ultrasound may be used to find the area. The anesthesia will be injected into the nerve group area. Your provider will again ask you to rate your symptoms. You may also be asked to keep a record of your symptoms and activities. Include the date when your symptoms return.

What will happen after a sympathetic nerve block:

You may be able to go home after feeling returns in the numbed area. Your healthcare provider may tell you to rest the day after the nerve block and then return to your normal activities.

Risks of a sympathetic nerve block:

You may have an allergic reaction, numbness, weakness, or difficulty walking. Your blood pressure may get too high or too low. You may have anxiety, dizziness, or seizures if the anesthesia gets into your blood vessels. You may have bleeding, or a blood clot may form if the needle goes into a blood vessel. The needle may also go into other parts of your body and cause damage. If the needle goes into a nerve, you may feel burning, tingling, prickling, or severe pain.

Call 911 if:

  • You have a seizure.
  • You have trouble breathing.

Seek care immediately if:

  • You develop hives or swelling.
  • You have severe pain.

Contact your healthcare provider if:

  • You are dizzy or have ringing in your ears.
  • You feel numbness or tingling around your mouth.
  • You have numbness or weakness in a limb 8 hours or more after your procedure.
  • You continue to bleed at the site of the needle insertion.
  • You have questions or concerns about sympathetic nerve blocks.


  • Decrease your activity the day of your procedure. Do not return to work until your healthcare provider says it is okay.
  • Be careful if your leg is numb. Your leg may not be able to support your weight. Do not drive until numbness is gone.

Follow up with your healthcare provider as directed:

Bring your symptom record to your follow-up visits. Write down your questions so you remember to ask them during your visits.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.