Last reviewed · How we verify
SODIUM IODIDE I 131
Iodide is transported and concentrated in thyroid cells, oxidized to iodinium, and used to iodinate thyroglobulin, with I-131's beta emission causing the therapeutic effect.
Sodium Iodide I 131 is a marketed drug primarily indicated for hyperthyroidism, with a well-established mechanism of action involving the concentration and beta emission within thyroid cells. Its key strength lies in the therapeutic efficacy of I-131's beta emission, which effectively targets and treats hyperthyroidism. The primary risk is the key composition patent expiry in 2028, which could lead to increased competition from generic alternatives.
At a glance
| Generic name | SODIUM IODIDE I 131 |
|---|---|
| Target | sodium-iodide symporter (NIS), thyroid peroxidase |
| Modality | Small molecule |
| Phase | FDA-approved |
| First approval | 1982 |
Mechanism of action
Iodide is actively transported into thyroid cells by the NIS protein and concentrated to high levels. It is then oxidized by thyroid peroxidase to iodinium, which iodinates tyrosine residues in thyroglobulin. The therapeutic effect is due to the beta emission from I-131.
Approved indications
- Hyperthyroidism
- Thyroid Carcinoma
Common side effects
- Local swelling
- Radiation sickness
- Sialadenitis
- Salivary gland dysfunction
- Bone marrow depression
- Lacrimal gland dysfunction
- Hypothyroidism
- Hyperthyroidism
- Thyrotoxic crisis
- Nausea
- Vomiting
- Gastritis
Serious adverse events
- Acute leukemia
- Solid cancer
- Pulmonary fibrosis
- Radiation pneumonitis
- Cerebral edema
- Leukopenia
- Thrombocytopenia
- Blood dyscrasia
- Anemia
- Bronchospasm
Drug interactions
- bone marrow depressants
- thionamide medications (e.g., propylthiouracil, methimazole, carbimazole)
- multivitamins containing iodide
- natural or synthetic thyroid hormones (triiodothyronine, thyroxine)
- iodide-containing foods (iodized salt, dairy products, egg yolks, seafood, turkey, liver)
- kelp, agar, carrageenan, Lugol solution
- saturated solution of potassium iodide
- topical iodide (e.g., surgical skin preparation)
- intravenous radiographic contrast agents (water soluble, lipophilic)
- amiodarone
Key clinical trials
- Trametinib in Increasing Tumoral Iodine Incorporation in Patients With Recurrent or Metastatic Thyroid Cancer (PHASE2)
- Study of Iopofosine I-131 (CLR 131) in Select B-Cell Malignancies (CLOVER-1) With Expansion in Waldenstrom (PHASE2)
- Novel Targeted Radiotherapy in Pediatric Patients With Inoperable Relapsed or Refractory HGG (PHASE1)
- S0016 Combination Chemotherapy With Monoclonal Antibody Therapy in Newly Diagnosed Non-Hodgkin's Lymphoma (PHASE3)
- Iodine I 131 Metaiodobenzylguanidine in Treating Patients With Recurrent, Progressive, or Refractory Neuroblastoma or Malignant Pheochromocytoma or Paraganglioma (PHASE2)
- Testing the Addition of 131I-MIBG or Lorlatinib to Intensive Therapy in People With High-Risk Neuroblastoma (NBL) (PHASE3)
- Vemurafenib and Cobimetinib for the Treatment of Patients With High Risk Differentiated Thyroid Carcinoma With BRAFV600E Mutation (PHASE2)
- Induction Therapy Including 131 I-MIBG and Chemotherapy in Treating Patients With Newly Diagnosed High-Risk Neuroblastoma Undergoing Stem Cell Transplant, Radiation Therapy, and Maintenance Therapy With Isotretinoin (PHASE1)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| FDA label | Mechanism, indications, dosing, boxed warnings, drug interactions |
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- SODIUM IODIDE I 131 CI brief — competitive landscape report
- SODIUM IODIDE I 131 updates RSS · CI watch RSS