Sodium Iodide I 131 (Therapeutic)

Before Using This Medicine

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 sodium iodide I 131, the following should be considered:

Diet - 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.

Pregnancy - Sodium iodide I 131 should not be used during pregnancy. This is to avoid exposing the fetus to radiation. Also, it may cause the newborn baby to have an underactive thyroid gland. A pregnancy test should be done prior to treatment with radioactive iodine if pregnancy is a possibility. Be sure you have discussed this with your doctor.

Breast-feeding - Sodium iodide I 131 passes into the breast milk and may cause unwanted effects, such as underactive thyroid, in the nursing baby. If you must receive this radiopharmaceutical, it will be necessary for you to stop breast-feeding several weeks before treatment. Be sure you have discussed this with your doctor.

Children - 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.

Older adults - 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.

Other medicines/tests - Tell your doctor if you have had an x-ray test recently for which you were given a radiopaque agent that contained iodine. The iodine contained in the radiopaque agent will reduce the amount of sodium iodide I 131 that your thyroid gland will accept. Also, tell your doctor if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other medical problems - The presence of other medical problems may affect the use of sodium iodide I 131. 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