Sodium Iodide I 131 (Oral Route)
Original Article: http://www.mayoclinic.com/health/drug-information/DR601253
US Brand Names
Sodium iodide I 131, also called radioactive iodine or radioiodide, is a radiopharmaceutical. Radiopharmaceuticals are radioactive agents, which may be used to diagnose some diseases by studying the function of the body's organs or to treat certain diseases.
Sodium iodide I 131 is used to treat an overactive thyroid gland and certain kinds of thyroid cancer. It is taken up mainly by the thyroid gland. In the treatment of hyperactive thyroid gland, radiation from the radioactive iodine damages the thyroid gland to bring its activity back down to normal. Larger doses of radioiodide are usually used after thyroid cancer surgery to destroy any remaining diseased thyroid tissue or to destroy thyroid cancer that has spread to other tissues.
When very small doses are given, a measure of the radioactivity taken up by the gland helps your doctor decide whether your thyroid gland is working properly. Also, an image of the organ on paper or a computer printout can be provided.
The information that follows applies only to the use of sodium iodide I 131 in treating an overactive or cancerous thyroid gland .
Sodium iodide I 131 is to be given only by or under the direct supervision of a doctor with specialized training in nuclear medicine or radiation oncology.
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Sodium iodide I 131 has been used in children and has not been shown to cause different side effects or problems than it does in adults. However, vomiting may be more difficult to manage in younger children.
Sodium iodide I 131 has been used in older people and has not been shown to cause different side effects or problems in older people than it does in younger adults.
|All Trimesters||X||Studies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. This drug should not be used in women who are or may become pregnant because the risk clearly outweighs any possible benefit.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Diarrhea or
- Vomiting—The radioactive iodine will be present in the diarrhea and vomit and will put you and others at a higher risk of radiation contamination; also, some of the dose will be lost, making the treatment less effective
- Kidney disease—Kidney disease may cause the radioiodide to stay in the body longer than usual, which may increase the risk of side effects
- If you have heart disease and are receiving sodium iodide I 131 to treat an overactive thyroid—The radiation may worsen the thyroid condition if antithyroid medicine and/or beta-blockers, such as propranolol, are not given before and after treatment
Your doctor may have special instructions for you to get ready for your treatment. If you have not received such instructions or you do not understand them, check with your doctor ahead of time.
If you eat large amounts of iodine-containing foods, such as iodized salt and seafoods, or cabbage, kale, rape (turnip-like vegetable), or turnips, the iodine contained in these foods will reduce the amount of this radiopharmaceutical that your thyroid gland will accept. Avoid these foods for at least 2 to 4 weeks before the treatment with radioiodide.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
There are no special precautions when this medicine is used in very small doses to help study the function of the thyroid. However, if you are receiving sodium iodide I 131 for an overactive thyroid or cancer of the thyroid, your doctor may tell you to follow some or all of these guidelines for 48 to 96 hours after receiving the medicine, to help reduce the chance of contaminating other persons:
- Do not kiss anyone, or handle or use another person's eating or drinking utensils, toothbrush, or bathroom glass.
- Do not have sex.
- Do not sit close to others, especially pregnant women, and do not hold children in your lap for long periods of time.
- Sleep alone.
- Wash the tub and sink after each use (including after brushing teeth).
- Wash your hands after using or cleaning the toilet .
- Use a separate towel and washcloth.
- Wash your clothes, bed linens, and eating utensils separately.
- Sodium iodide I 131 is passed in the urine. To prevent contamination of your home, flush the toilet twice after you urinate .
To increase the flow of urine and lessen the amount of radioactive iodine in your body, drink plenty of liquids and urinate often.
If you were treated with sodium iodide I 131 for an overactive thyroid, your doctor may want to check the level of thyroid hormone in your blood every 2 to 3 months during the first year, and once a year thereafter. This is to make sure that your thyroid has not become underactive.
Studies have not shown that sodium iodide I 131 increases the chance of cancer or other long-term problems. When used to treat an overactive thyroid gland, sodium iodide I 131 may cause the patient to have an underactive thyroid gland after treatment. The thyroid gland may become underactive even several years after treatment for hyperthyroidism. Before receiving this medicine, be sure you have discussed its use with your doctor.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:After treatment of overactive thyroidSymptoms of an underactive thyroid
- Changes in menstrual periods
- Dry, puffy skin
- Muscle aches
- Thinning of hair (temporary)—may occur 2 to 3 months after treatment
- Unusual tiredness or weakness
- Weight gain
- Excessive sweating
- Fast heartbeat
- Unusual irritability
- Unusual tiredness
- Black, tarry stools
- Blood in urine or stools
- Cough or hoarseness
- Fever or chills
- Lower back or side pain
- Painful or difficult urination
- Pinpoint red spots on skin
- Unusual bleeding or bruising
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:Less commonAfter treatment of overactive thyroid or cancer of the thyroid
- Neck tenderness or swelling
- Sore throat
- Loss of taste (temporary)
- Nausea and vomiting (temporary)
- Tenderness of salivary glands
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.