sodium iodide 131

Class: Radiopharmaceutical

Generic Name: Sodium Iodide (SOE-dee-um  EYE-oh-dyde) I 131

Trade Name: Iodotope®

How is this drug used? Sodium iodide I 131 is FDA approved for the treatment of some types of thyroid cancer. It is important for patients to remember that physicians have the ability to prescribe medication for conditions other than those for which the drug has been approved by the FDA. Patients who have received a prescription of this drug for a condition other than which it is approved may wish to discuss this issue with their physician.

What is the mechanism of action? Sodium iodide 131 belongs to a class of agents referred to as radiopharmaceuticals. Sodium iodide I 131 selectively collects in the thyroid, emitting radiation to kill the cancer cells and shrink the cancer.

How is sodium iodide I 131 given (administered)? Sodium iodide I 131 may be administered orally as a capsule, or as a solution, and the dose depends on several factors, including the condition being treated, the size of the patient, the particular regimen being used and the overall health of the patient. Patients may receive special instructions from their physician to get ready for treatment.

How are patients monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with sodium iodide I 131.  Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver.  Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy.

What are the most common (occur in 10 29% of patients) side effects of treatment with sodium iodide I 131?

 Low levels of white blood cells increases risk of infection

 Low levels of red blood cells increases risk of anemia

 Low levels of platelets increases risk of bleeding

 Nausea and vomiting

 Increase in symptoms caused by the cancer

 Tenderness, swelling, pain of the neck

 Sore throat


 Thinning of hair

 Allergic-type reactions

 Loss of taste (temporary)

 Tenderness of salivary glands



What are the possible late side effects of treatment with sodium iodide I 131? Patients treated with sodium iodide I 131 are at an increased risk of developing a secondary malignancy.  A secondary malignancy is a new and unrelated cancer that occurs in an individual as a result of previous treatment with radiation or chemotherapy.  Patients should ask their physician about the possibility of developing a secondary malignancy as a result of their treatment.



 Maintain adequate rest and nutrition.

 Wear sunscreen and protective clothing and try to minimize sun exposure.


 Over the counter pain medication may help alleviate some pain caused by treatment. Patients should speak with their physician about this issue.

 Patients should prepare family members or roommates prior to treatment of the possible radiation precautions that need to be taken.

 If possible, the patient should avoid large crowds or persons who are sick or not feeling well, as this drug may leave some patients susceptible to infection.

 Wash hands often to reduce the risk of infection.

 Avoid activities that may cause injury or bruising.


 Eat small meals frequently to help alleviate nausea.







 Patients are being treated with a radioactive substance, and radioactivity will be present in excreted urine. Patients need to discuss precautions against radioactivity with their physician and how long precautions should be followed.

 A toilet, versus a urinal should be used whenever possible. The toilet should be flushed several times immediately after every use. If urine spills outside the toilet, it should be cleaned up immediately and completely, and patients should wash their hands thoroughly. If blood or urine gets onto clothing, bed sheets, towels, etc., these items should be washed separately from other items.

 Patients should not use another persons eating or drinking utensils, towels or toothbrush.

 Wash eating utensils and clothes separately.

 Patients should not sit close to others, especially pregnant women.

 Patients should not engage in sex while being treated with sodium iodide I 131.



When should patients notify their physician?

 Difficulty breathing

 Unusual bleeding (nosebleeds, bruising, pin sized red dots on skin, blood in urine or stool)

 Chest pain

 Swelling, pain, redness of one extremity and not the other

 Pain, lower back pain, side pain

 Swelling of feet or ankles

 Flu or cold-like symptoms fever, chills, sore throat, cough, hoarseness

 Signs of infection redness, swelling, pus, tenderness, painful or difficulty urination

 Severe fatigue

What is a package insert?


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