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Sodium iodide I 131 (By mouth)

Sodium Iodide I 131 (SOE-dee-um EYE-oh-dide I 131)

Treats an overactive thyroid and thyroid cancer. This medicine is a radioactive substance.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. You should not receive it if you had an allergic reaction to sodium iodide I 131, if you are pregnant or breastfeeding, or have nausea or vomiting.

How to Use This Medicine:

Capsule, Liquid

  • A nurse or other trained health professional will give you this medicine.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how sodium iodide I 131 works. Tell your doctor if you are also using amiodarone, lithium, perchlorate, phenylbutazone, or tolbutamide. Also tell your doctor if you are using any thyroid or antithyroid medicine (such as thyroxine, liothyronine, carbimazole, propylthiouracil), steroids, blood thinners (such as warfarin), vitamins, cough medicine, allergy medicine, sulfa drugs, skin cleansers, or antiseptics (such as povidone).

Warnings While Using This Medicine:

  • This medicine can harm an unborn baby. Both men and women should use 2 forms of birth control to avoid pregnancy. Do this for at least 6 months after treatment ends. If a pregnancy occurs, tell your doctor right away.
  • Tell your doctor if you have kidney disease, heart disease, asthma, or a history of sulfite allergy.
  • This medicine may cause the following problems:
    • Thyroid inflammation
    • Increased risk of cancer
    • Temporary infertility
  • You will be exposed to radiation while using this medicine. Talk with your doctor about precautions that you should take for yourself and for the people around you.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain, fast heartbeat
  • Fever, extreme weakness, restlessness, confusion
  • Painful, dry, burning, watery, itchy eyes or mouth
  • Trouble or pain when swallowing, sore or swollen neck
  • Unusual bleeding or bruising

If you notice these less serious side effects, talk with your doctor:

  • Cough, mild sore throat
  • Mild nausea or vomiting

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 5/1/2020

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