EUTHYROX (levothyroxine sodium) · EMD SERONO
Euthyrox provides a synthetic form of the thyroid hormone T4 for pediatric and adult patients with various forms of hypothyroidism, including primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) conditions that are congenital or acquired. Additionally, it is used as an adjunct to surgery and radioiodine therapy to manage thyrotropin-dependent well-differentiated thyroid cancer by suppressing TSH. It is not indicated for the treatment of hypothyroidism during the recovery phase of subacute thyroiditis or for the suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients.
How EUTHYROX Works
Levothyroxine (T4) and its active metabolite, triiodothyronine (T3), diffuse
Details
- Status
- Discontinued
- First Approved
- 2002-05-31
- Routes
- ORAL
- Dosage Forms
- TABLET
EUTHYROX Approval History
What EUTHYROX Treats
2 indicationsEUTHYROX is approved for 2 conditions since its original approval in 2002. These indications span multiple therapeutic areas including oncology, immunology, and more.
EUTHYROX Boxed Warning
NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including EUTHYROX, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their an...
WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including EUTHYROX, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects [see Adverse Reactions (6) , Drug Interactions (7.7) , and Overdosage (10) ] . WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS See full prescribing information for complete boxed warning. Thyroid hormones, including EUTHYROX, should not be used for the treatment of obesity or for weight loss. Doses beyond the range of daily hormonal requirements may produce serious or even life-threatening manifestations of toxicity ( 6 , 10 ).
EUTHYROX Competitive Set
ProThree rings of competition based on shared molecular targets and treated indications.
Direct competitors
Same target(s) AND same indication — head-to-head.
Indication competitors
Same indication, different mechanism — what else might this patient receive?
Filters applied: drops same-active-ingredient (505(b)(2) reformulations), route-mismatch (topical vs systemic), and cross-therapeutic-area matches in same-indication rings.
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EMD SERONO's other novel FDA approvals
Other CDER-designated drugs from the same sponsor (2016–2025).
Clinical Trial Registry
6 trials| Trial | Sponsor ID | Phase | Status | Title |
|---|---|---|---|---|
| NCT06073665 DOT4 | 1R01AG081698-01, #853300 R01AG081698 | Ph 4 | recruiting | Dosing of LT4 in Older Individuals |
| NCT05228184 results posted | 20US-T414 | Ph 4 | terminated | Use of Tirosint®-SOL or Tablet Formulations of Levothyroxine in Pediatric Patients With Congenital Hypothyroidism (CH) |
| NCT05823012 results posted | XP-8121-120 | Ph 2 | completed | Study of XP-8121 For the Treatment of Adult Subjects With Hypothyroidism |
| NCT04878614 | IRB#20-002097 | Ph 4 | terminated | Comparison of Levothyroxine Formulation in Hypothyroid Patients With Enteral Feeding |
| NCT03281083 | MRN-01-NAFLD-01 | Ph 2 | terminated | Levothyroxine for Non-Alcoholic Fatty Liver Disease (NAFLD) |
| NCT00921050 | EN_LC_P136 | Ph 2, Ph 3 | completed | Subclinical Hypothyroidism and Mind in the Elderly |
Active Pipeline
Ongoing clinical trials by development phase
Key Completed Trials
Completed studies with published results, ranked by significance
Trial Timeline
Full development history with FDA approval milestones
Understanding FDA Approval Types
| Count | Type | What it means |
|---|---|---|
| - | ORIG | Original approval - drug first enters market |
| - | SUPPL - Efficacy | New indication (new disease/condition approved) |
| - | SUPPL - Labeling | Label text changes (warnings, dosing updates) |
| - | SUPPL - Manufacturing | Production changes (new facility) |
| - | SUPPL - Chemistry | Formulation changes (new dosage strength) |
Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.
EUTHYROX FDA Label Details
Indications & Usage
FDA Label (PDF)EUTHYROX is L-thyroxine (T4) indicated in pediatric and adult patients for: Hypothyroidism: As replacement in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) suppression: As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer. Limitations of Use: - Not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients. - Not indicated for treatment of hypothyroid...
WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including EUTHYROX, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffecti...
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Data Sources
Data sourced from official FDA and NIH databases. Click links to verify on original sources.