With careful titration, SYNTHROID can help manage your patient's hypothyroidism. SYNTHROID should be taken as a single daily dose.
25 mcg
orange
50 mcg
white
75 mcg
violet
88 mcg
olive
100 mcg
yellow
112 mcg
rose
125 mcg
brown
137 mcg
turquoise
150 mcg
orange
175 mcg
lilac
200 mcg
pink
300 mcg
green
Tablets shown not actual size and may not represent actual color.
With careful titration, SYNTHROID can help manage your patient's hypothyroidism. SYNTHROID should be taken as a single daily dose.
25 mcg
orange
50 mcg
white
75 mcg
violet
88 mcg
olive
100 mcg
yellow
112 mcg
rose
125 mcg
brown
137 mcg
turquoise
150 mcg
blue
175 mcg
lilac
200 mcg
pink
300 mcg
green
Tablets shown not actual size and may not represent actual color.
25 mcg
orange
50 mcg
white
75 mcg
violet
88 mcg
olive
100 mcg
yellow
112 mcg
rose
125 mcg
brown
137 mcg
turquoise
150 mcg
blue
175 mcg
lilac
200 mcg
pink
300 mcg
green
Tablets shown not actual size and may not represent actual color.
With careful titration, SYNTHROID can help manage your patient's hypothyroidism. SYNTHROID should be taken as a single daily dose.
Thyroid disease spectrum
Abbreviations: AACE, American Association of Clinical Endocrinologists; ATA, American Thyroid Association; NACB, National Academy of Clinical Biochemistry
TSH levels alone may not be diagnostic of a thyroid disorder. Additional laboratory testing and clinical findings may be necessary.
The goal is to achieve steady TSH levels within the appropriate therapeutic range.
Dosing must be individualized based on your patient’s age, weight, cardiovascular status, concomitant medical conditions (including pregnancy), concomitant medications, co-administered food, and the specific etiology of the condition being treated.2 See full prescribing information for dosing in specific patient populations.
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Tablets shown not actual size and may not represent actual color.
| Patient Population | Starting Dose | Dose Adjustment & Titration |
|---|---|---|
| Adults diagnosed with hypothyroidism | Full replacement dose is 1.6 mcg/kg/day. Some patients require a lower starting dose. | Titrate dosage by 12.5 to 25 mcg increments every 4 to 6 weeks, as needed until the patient is euthyroid. |
| Adults at risk for atrial fibrillation or with underlying cardiac disease | Lower starting dose (less than 1.6 mcg/kg/day) | Titrate dosage every 6 to 8 weeks as needed until the patient is euthyroid. |
| Geriatric patients | Lower starting dose (less than 1.6 mcg/kg/day) | Titrate dosage every 6 to 8 weeks as needed until the patient is euthyroid |
| Pregnant patients with pre-existing primary hypothyroidism with serum TSH above normal trimester-specific range | Pre-pregnancy dosage may increase during pregnancy | Increase SYNTHROID dosage by 12.5 to 25 mcg per day. Monitor TSH every 4 weeks until a stable dose is reached and serum TSH is within normal trimester-specific range. Reduce SYNTHROID dosage to pre-pregnancy levels immediately after delivery. Monitor serum TSH 4 to 8 weeks postpartum. |
| Pregnant patients with new onset hypothyroidism (TSH ≥10 mIU per liter) |
1.6 mcg/kg/day | Monitor serum TSH every 4 weeks and adjust SYNTHROID dosage until serum TSH is within normal trimester-specific range. |
| Pregnant patients with new onset hypothyroidism (TSH <10 mIU per liter) |
1.0 mcg/kg/day | Monitor serum TSH every 4 weeks and adjust SYNTHROID dosage until serum TSH is within normal trimester-specific range. |
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
Select pill below to enlarge and see dosage
The FDA has determined that certain levothyroxine products are therapeutically equivalent, and can be substituted at the pharmacy with the full expectation that the substituted product will produce the same clinical effect and safety profile as the reference product.8
Tablets shown not actual size and may not represent actual color.
Download a PDF of the "How to take SYNTHROID" brochure to share with your patient
Select pill below to enlarge and see dosage
The FDA has determined that certain levothyroxine products are therapeutically equivalent, and can be substituted at the pharmacy with the full expectation that the substituted product will produce the same clinical effect and safety profile as the reference product.8
Tablets shown not actual size and may not represent actual color.
Download a PDF of the "How to take SYNTHROID" brochure to share with your patient
For secondary or tertiary hypothyroidism, serum TSH is not a reliable measure of SYNTHROID dosage adequacy and should not be used to monitor therapy. Use the serum free-T4 level to titrate SYNTHROID dosing until the patient is clinically euthyroid and the serum free-T4 is restored to upper half of normal range.2
Certain foods may decrease absorption and require dosing adjustments, including2:
Grapefruit juice delays the absorption of SYNTHROID and reduces its bioavailability.2
Iron, calcium supplements, and antacids can also decrease absorption.2
Many drugs can exert effects on thyroid hormone pharmacokinetics and metabolism (eg, absorption, synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to SYNTHROID.2
Drugs That May Decrease T4 Absorption (Hypothyroidism) |
|
|---|---|
| Potential impact: Concurrent use may reduce the efficacy of SYNTHROID by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. | |
| Drug or Drug Class | Effect |
| Phosphate Binders (e.g., calcium carbonate, ferrous sulfate, sevelamer, lanthanum) |
Phosphate binders may bind to levothyroxine. Administer SYNTHROID at least 4 hours apart from these agents. |
| Orlistat | Monitor patients treated concomitantly with orlistat and SYNTHROID for changes in thyroid function. |
| Bile Acid Sequestrants: (e.g., colesevelam, cholestyramine, colestipol) |
Bile acid sequestrants and ion exchange resins are known to decrease levothyroxine absorption. Administer SYNTHROID at least 4 hours prior to these drugs or monitor TSH levels. |
| Ion Exchange Resins: (e.g., Kayexalate) |
|
| Proton Pump Inhibitors Sucralfate Antacids (e.g., aluminum & magnesium hydroxides, simethicone)
|
Gastric acidity is an essential requirement for adequate absorption of levothyroxine. Sucralfate, antacids, and proton pump inhibitors may cause hypochlorhydria, affect intragastric pH, and reduce levothyroxine absorption. Monitor patients appropriately. |
Drugs That May Alter T4 and Triiodothyronine (T3) Serum Transport
|
|
|---|---|
| Drug or Drug Class | Effect |
| Clofibrate Estrogen-containing Oral Contraceptives Estrogens (oral) Heroin/Methadone 5-Fluorouracil Mitotane Tamoxifen |
These drugs may increase serum thyroxine-binding globulin (TBG) concentration. |
| Androgens/Anabolic Steroids Asparaginase Glucocorticoids Slow-release Nicotinic Acid |
These drugs may decrease serum TBG concentration. |
| Potential impact (below): Administration of these agents with SYNTHROID results in an initial transient increase in FT4. Continued administration results in a decrease in serum T4 and normal FT4 and TSH concentrations. | |
| Salicylates (>2 g/day) | Salicylates inhibit binding of T4 and T3 to TBG and transthyretin. An initial increase in serum FT4 is followed by return of FT4 to normal levels with sustained therapeutic serum salicylate concentrations, although total T4 levels may decrease by as much as 30%. |
| Other Drugs: Carbamazepine Furosemide (>80 mg IV) Heparin Hydantoins NSAIDS - Fenamates |
These drugs may cause protein-binding site displacement. Furosemide has been shown to inhibit the protein binding of T4 to TBG and albumin, causing an increase in free T4 fraction in serum. Furosemide competes for T4-binding sites on TBG, prealbumin, and albumin, so that a single high dose can acutely lower the total T4 level. Phenytoin and carbamazepine reduce serum protein binding of levothyroxine, and total and free T4 may be reduced by 20% to 40%, but most patients have normal serum TSH levels and are clinically euthyroid. Closely monitor thyroid hormone parameters. |
Drugs That May Alter Hepatic Metabolism of T4 (Hypothyroidism) |
|
|---|---|
| Potential impact: Stimulation of hepatic microsomal drug-metabolizing enzyme activity may cause increased hepatic degradation of levothyroxine, resulting in increased SYNTHROID requirements. | |
| Drug or Drug Class | Effect |
| Phenobarbital Rifampin |
Phenobarbital has been shown to reduce the response to thyroxine. Phenobarbital increases L-thyroxine metabolism by inducing uridine 5’-diphospho-glucuronosyltransferase (UGT) and leads to lower T4 serum levels. Changes in thyroid status may occur if barbiturates are added or withdrawn from patients being treated for hypothyroidism. Rifampin has been shown to accelerate the metabolism of levothyroxine. |
Drugs That May Decrease Conversion of T4 to T3 |
|
|---|---|
| Potential impact: Administration of these enzyme inhibitors decreases the peripheral conversion of T4 to T3, leading to decreased T3 levels. However, serum T4 levels are usually normal but may occasionally be slightly increased. | |
| Drug or Drug Class | Effect |
| Beta-adrenergic antagonists (eg, Propranolol >160 mg/day) |
In patients treated with large doses of propranolol (>160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid. Actions of particular beta-adrenergic antagonists may be impaired when a hypothyroid patient is converted to the euthyroid state. |
| Glucocorticoids (eg, Dexamethasone ≥4 mg/day) |
Short-term administration of large doses of glucocorticoids may decrease serum T3 concentrations by 30% with minimal change in serum T4 levels. However, long-term glucocorticoid therapy may result in slightly decreased T3 and T4 levels due to decreased TBG production (see above). |
| Other drugs: Amiodarone |
Amiodarone inhibits peripheral conversion of levothyroxine (T4) to triiodothyronine (T3) and may cause isolated biochemical changes (increase in serum free T4, and decreased or normal free-T3) in clinically euthyroid patients. |
175 mcg 
150 mcg 
137 mcg 
125 mcg 
112 mcg 
100 mcg 
88 mcg 
200 mcg 
75 mcg Hypothyroidism
SYNTHROID® (levothyroxine sodium) tablets for oral use is an L-thyroxine (T4) 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
SYNTHROID 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 thyroid cancer.
SYNTHROID is not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients, as there are no clinical benefits and overtreatment with SYNTHROID may induce hyperthyroidism.
SYNTHROID is not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis.
Thyroid hormones, including SYNTHROID, 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.
US-SYNT-220356