This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.
WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including TIROSINT-SOL, 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 TIROSINT-SOL, 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 ).
Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.
is L-thyroxine (T4) indicated in adult and pediatric patients, including neonates, for: Hypothyroidism - As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism ( 1 ) 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 ( 1 ) Limitations of Use Not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients ( 1 ) Not indicated for treatment of transient hypothyroidism during the recovery phase of subacute thyroiditis ( 1 ) Hypothyroidism TIROSINT-SOL is indicated in adult and pediatric patients, including neonates, as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) Suppression TIROSINT-SOL is indicated in adult and pediatric patients, including neonates, as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyro...
TIROSINT-SOL is contraindicated in patients with: Hypersensitivity to glycerol, the inactive ingredient in TIROSINT-SOL [see Adverse Events (6) ]. Uncorrected adrenal insufficiency [see Warnings and Precautions (5.4) ] Hypersensitivity to glycerol ( 4 ) Uncorrected adrenal insufficiency ( 4 )
Serious risks related to overtreatment or undertreatment with TIROSINT-SOL: Titrate the dose of TIROSINT-SOL carefully and monitor response to titration. ( 5.1 ) Cardiac adverse reactions in the elderly and in patients with underlying cardiovascular disease : Initiate TIROSINT-SOL at less than the full replacement dose because of the increased risk of cardiac adverse reactions, including atrial fibrillation. ( 2.3 , 5.2 , 8.5 ) Myxedema coma: Do not use oral thyroid hormone drug products to treat myxedema coma. ( 5.3 ) Acute adrenal crisis in patients with concomitant adrenal insufficiency: Treat with replacement glucocorticoids prior to initiation of TIROSINT‑SOL treatment. ( 5.4 ) Worsening of diabetic control: therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing thyroid hormone therapy. ( 5.5 ) Decreased bone mineral density associated with thyroid hormone over-replacement: Over-replacement can increase bone resorption and decrease bone mineral density. Give the lowest effective dose. 5.6 ) 5.1 Serious Risks Related t...
Adverse reactions associated with TIROSINT-SOL therapy are primarily those of hyperthyroidism due to therapeutic overdosage [see Warnings and Precautions (5) and Overdosage (10) ]. They include the following: General: fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating Central nervous system: headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia Musculoskeletal: tremors, muscle weakness, muscle spasm Cardiovascular: palpitations, tachycardia, arrhythmias, increased pulse and blood pressure, heart failure, angina, myocardial infarction, cardiac arrest Respiratory : dyspnea Gastrointestinal (GI): diarrhea, vomiting, abdominal cramps, elevations in liver function tests Dermatologic: hair loss, flushing, rash Endocrine: decreased bone mineral density Reproductive: menstrual irregularities, impaired fertility Seizures have been reported rarely with the institution of levothyroxine therapy. Adverse reactions associated with TIROSINT-SOL are primarily those of hyperthyroidism due to therapeutic overdosage including: arrhythmias, myocardial infarction, dyspnea, muscle spasm, headache, nervousness, irritability, insomnia,...
RECENT MAJOR CHANGES Indications and Usage ( 1 ) 11/2023 Dosage and Administration ( 2.1 ) 11/2023 Dosage and Administration ( 2.2 ) 11/2023 Dosage and Administration ( 2.3 ) 11/2023 Warnings and Precautions ( 5.1 ) 11/2023 Warnings and Precautions ( 5.4 ) 11/2023
Source: FDA SPL label for Tirosint SOL (IBSA Pharma Inc.), effective 20260327. Full label on DailyMed.
These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|
| 41,623 | 41,002 | 35,395 | 33,560 | 30,547 | 21,841 | 30,783 | 15,221 |
1,386 reports blaming this drug for every million Medicare prescriptions filled, which is 0.5× the typical drug on this site. (67,443 reports in 2024–2026, against 48,650,486 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)
Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.
| Date | Class | Firm | Reason |
|---|---|---|---|
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
| 08/2026 | Class II | ACCORD HEALTHCARE, INC. | Subpotent Drug |
Class I = reasonable probability of serious harm. Class II = temporary or reversible harm. Class III = unlikely to harm. Most generic recalls are manufacturing or labeling defects for one lot, not a verdict on the molecule.
Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.
In 2024, drug companies reported $579,638 in payments to US physicians and hospitals tied to this drug across 24,141 transactions (Synthroid $232,612, Tirosint $214,537, Unithroid $132,490).
No pending federal MDL names this drug or its brands.
Not named in any federal pharmaceutical settlement of $100M or more on record.
Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.
| Product | Fills | $/fill |
|---|---|---|
| Levothyroxine Sodium | 43,253,940 | $11 |
| Synthroid | 4,990,576 | $70 |
| Levoxyl | 157,517 | $39 |
| Unithroid | 94,138 | $44 |
| Euthyrox | 69,130 | $7 |
| Tirosint | 63,867 | $260 |
| Tirosint-Sol | 11,238 | $232 |
| Levo-T | 9,029 | $20 |
No same-class alternatives found in RxClass.