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Sodium Iodide I 131 Therapeutic Capsules for oral use


Sodium Iodide I 131 Capsules Therapeutic are indicated for the treatment of hyperthyroidism and thyroid carcinomas that take up iodide. Palliative effects may be observed in patients with advanced thyroid malignancy if the metastatic lesions take up iodide.



  • Sodium Iodide I 131 Capsules Therapeutic is contraindicated in:
    • Patients with vomiting and diarrhea.
    • The treatment of thyroid malignancies shown to have no iodide uptake, which include the majority of medullary and anaplastic carcinomas.
    • Pregnancy.


  • Sodium iodide I-131 may cause thyroiditis with gland enlargement and release of thyroid hormone, particularly when used to treat hyperthyroidism. The thyroiditis may cause or worsen hyperthyroidism, and may cause thyroid storm.
  • Enhanced TSH secretion, e.g., following discontinuation of anti-thyroid medications, or the administration of TSH to enhance sodium iodide I-131 uptake, may cause thyroid enlargement and obstructive complications of the trachea, esophagus, or blood vessels in the neck.
  • Radiation-induced toxicities, including dose-dependent fatalities, have been reported following sodium iodide I-131 therapy including:
    • increased risk of neoplasia, as well as risks for hematopoietic suppression
    • salivary and lacrimal gland toxicity is common and may manifest as conjunctivitis, xerophthalmia, epiphora, sialadenitis and xerostomia.
  • Hypersensitivity reactions, including rash and hives have been reported following administration of sodium iodide I-131. Sodium iodide I-131 capsules may contain sodium bisulfite, a sulfite that may cause allergic-type reactions, including anaphylactic symptoms and life-threatening or less severe asthmatic episodes.
  • Transplacental passage of sodium iodide I-131 can cause severe and possibly irreversible hypothyroidism in neonates.
  • Transient, dose-related impairment of testicular function has been reported after sodium iodide I-131 therapy.  Consider sperm banking for men who are anticipated to receive a high cumulative sodium iodide I-131 dose (e.g., greater than 14 GBq). In females, transient ovarian failure has been observed after sodium iodide I-131 therapy.
  • Unwanted radiation exposure can occur from handling and administration of radiopharmaceuticals or from contaminated waste products, including urine and feces.
  • Radiopharmaceuticals should be used only by or under the direction of physicians who are qualified by training and experience in the safe use and handling of radionuclides and whose experience and training have been approved by the appropriate governmental agency authorized to license the use of radionuclides.
  • Sodium iodide I-131 capsules emit radiation and must be handled with safety measures to minimize inadvertent radiation exposure to clinical personnel and patients.


  • Serious adverse reactions may include radiation-induced thyroiditis, thyroid stimulation hormone and thyroid enlargement, radiation-induced toxicities, hypersensitivity reactions, fetal risk, transient infertility and radiation exposure to others, malignancies and hematopoietic toxicities including fatalities.
  • Common adverse reactions include nausea, vomiting, chest pain, tachycardia, itching, rash and hives.


  • Pregnancy Category X. Contraindicated in pregnant women.
  • Breastfeeding and breast-pumping should be discontinued for at least four weeks before administration of sodium iodide I-131. If sodium iodide I-131 is administered in the postpartum period, the lactating mother should not breast-feed the infant.  Breastfeeding may resume with the birth of another child, if the mother does not receive sodium iodide I-131 during that postpartum period.
  • Safety and effectiveness in pediatric patients have not been established.
  • Because elderly patients are more likely to have decreased renal function and co-morbid conditions, enhanced evaluation, dose-selection consideration and follow-up may be necessary for elderly patients receiving sodium iodide I-131 therapy.
  • Patients with renal impairment are subject to decreased excretion of sodium iodide I-131 and increased radiation exposure.

How Supplied

Distribution Direct
Calibration Day Second Friday following date of manufacture
Expiration 17 days post manufacture
Storage Conditions Controlled room temperature 20°-25°C (68°-77°F)

Order Information

Description Qty Unit Size Order # 11 Digit NDC
Vial, capsule - *see attached Decay-Order Chart for size available the day you will administer the capsule 1 each N452* See attached Package Insert for this product


What is the half-life of sodium iodide I-131 therapeutic capsules?I-131 decays by beta emission and associated gamma emission with a physical half-life of 8.04 days.
What is the expiration date?The expiration date is 17 days post manufacture.
What is the recommended dose for hyperthyroidism?See package insert for dosing information.
What is the recommended dose for thyroid carcinoma?See package insert for dosing information.
Should a mother cease breastfeeding after administration of an I 131 therapeutic dose?Yes, radioiodine is excreted in human milk during lactation. Therefore, formula feedings should be substituted for breast feedings. Please refer to the package insert for additional information.
Who do I contact for additional safety or usage questions?Call Mallinckrodt Product Monitoring at 800.778.7898.