Iodide Ion I-131
Iodide Ion I-131 is a radioactive form of iodine used primarily to treat thyroid disorders. It works by targeting thyroid tissue, which naturally absorbs iodine, where it delivers localized radiation to destroy overactive cells or remaining cancerous tissue after surgery.
A radioactive iodine treatment that selectively targets and destroys thyroid tissue for hyperthyroidism and thyroid cancer.
Key facts at a glance
- RxNorm
- 1546415
- Generic
- Iodide Ion I-131
- Class
- pin-variant
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Treatment of hyperthyroidism (Graves' disease, toxic nodular goiter), ablation of remaining thyroid tissue after thyroidectomy for thyroid cancer, and in some cases, differentiated thyroid cancer metastases.
The thyroid gland actively takes up iodine for hormone production. I-131 accumulates in thyroid cells and emits beta radiation that causes localized cellular damage and destruction of the tissue over weeks to months.
Contraindicated in pregnancy and breastfeeding. Requires radiation safety precautions including temporary avoidance of close contact with others. May cause hypothyroidism requiring lifelong thyroid hormone replacement. Men should avoid conception for several months post-treatment. Treatment typically performed in specialized facilities with specific post-treatment instructions.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 28, 2026. · Read our editorial policy