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FDA Drug information

Levothyroxine Sodium

Read time: 6 mins
Marketing start date: 18 Jun 2024

Summary of product characteristics


Adverse Reactions

6 ADVERSE REACTIONS Adverse reactions associated with levothyroxine sodium tablets therapy are primarily those of hyperthyroidism due to therapeutic overdosage [see Warnings and Precautions (5), 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: 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 in Pediatric Patients Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in pediatric patients receiving levothyroxine therapy. Overtreatment may result in craniosynostosis in infants who have not undergone complete closure of the fontanelles, and in premature closure of the epiphyses in pediatric patients still experiencing growth with resultant compromised adult height. Hypersensitivity Reactions Hypersensitivity reactions to inactive ingredients have occurred in patients treated with thyroid hormone products. These include urticaria, pruritus, skin rash, flushing, angioedema, various gastrointestinal symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness, and wheezing. Hypersensitivity to levothyroxine itself is not known to occur. Adverse reactions associated with levothyroxine sodium tablets therapy are primarily those of hyperthyroidism due to therapeutic overdosage: arrhythmias, myocardial infarction, dyspnea, muscle spasm, headache, nervousness, irritability, insomnia, tremors, muscle weakness, increased appetite, weight loss, diarrhea, heat intolerance, menstrual irregularities, and skin rash. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceuticals, Inc. at 1-800-399-2561 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Contraindications

4 CONTRAINDICATIONS Levothyroxine sodium tablets are contraindicated in patients with uncorrected adrenal insufficiency [see Warnings and Precautions (5.4)] . Uncorrected adrenal insufficiency. ( 4 )

Description

11 DESCRIPTION Levothyroxine sodium tablets USP is L-thyroxine (T4) and contains synthetic crystalline L-3,3',5,5' tetraiodothyronine sodium salt. Synthetic T4 is chemically identical to that produced in the human thyroid gland. Levothyroxine (T4) sodium has an empirical formula of C 15 H 10 I 4 N NaO 4 •xH 2 O, molecular weight of 798.85 (anhydrous), and structural formula as shown: Levothyroxine sodium tablets USP for oral administration are supplied in the following strengths: 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg, and 300 mcg. Each levothyroxine sodium tablets USP contains the inactive ingredients corn starch, croscarmellose sodium, magnesium stearate, mannitol and sodium bicarbonate. Table 9 provides a listing of the color additives by tablet strength: Strength (mcg) Color additive(s) 25 FD&C Yellow No. 6 Aluminum Lake* 50 FD&C Blue 1 Aluminum Lake 75 FD&C Red No. 40 Aluminum Lake, FD&C Blue No. 2 Aluminum Lake 88 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, D&C Yellow No. 10 Aluminum Lake 100 FD&C Yellow No. 6 Aluminum Lake*, D&C Yellow No. 10 Aluminum Lake 112 D&C Red No. 27 Aluminum Lake 125 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, FD&C Red No. 40 Aluminum Lake, FD&C Blue No. 2 Aluminum Lake 137 FD&C Blue No. 1 Aluminum Lake 150 FD&C Blue No. 2 Aluminum Lake 175 FD&C Blue No. 1 Aluminum Lake, D&C Red No. 27 Aluminum Lake 200 FD&C Red No. 40 Aluminum Lake 300 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, D&C Yellow No. 10 Aluminum Lake *Note – FD&C Yellow No. 6 Aluminum Lake is peach in color. image-1

Dosage And Administration

2 DOSAGE AND ADMINISTRATION Administer once daily, preferably on an empty stomach, one-half to one hour before breakfast. ( 2.1 ) Administer at least 4 hours before or after drugs that are known to interfere with absorption. ( 2.1 ) Evaluate the need for dose adjustments when regularly administering within one hour of certain foods that may affect absorption. ( 2.1 ) Starting dose depends on a variety of factors, including age, body weight, cardiovascular status, and concomitant medications. Peak therapeutic effect may not be attained for 4 to 6 weeks. ( 2.2 ) See full prescribing information for dosing in specific patient populations. ( 2.3 ) Adequacy of therapy determined with periodic monitoring of TSH and/or T4 as well as clinical status. ( 2.4 ) 2.1 Important Administration Instructions Administer levothyroxine sodium tablets as a single daily dose, on an empty stomach, one-half to one hour before breakfast. Administer levothyroxine sodium tablets at least 4 hours before or after drugs known to interfere with levothyroxine sodium tablets absorption [see Drug Interactions ( 7.1 )] . Evaluate the need for dosage adjustments when regularly administering within one hour of certain foods that may affect levothyroxine sodium tablets absorption [see Dosage and Administration (2.2 and 2.3), Drug Interactions (7.9) and Clinical Pharmacology (12.3)] . Administer levothyroxine sodium tablets to pediatric patients who cannot swallow intact tablets by crushing the tablet, suspending the freshly crushed tablet in a small amount (5 to 10 mL) of water and immediately administering the suspension by spoon or dropper. Ensure the patient ingests the full amount of the suspension. Do not store the suspension. Do not administer in foods that decrease absorption of levothyroxine sodium tablets, such as soybean-based infant formula [see Drug Interactions (7.9)] . 2.2 Important Considerations for Dosing The dosage of levothyroxine sodium tablets for hypothyroidism or pituitary TSH suppression depends on a variety of factors including: the patient's age, body weight, cardiovascular status, concomitant medical conditions (including pregnancy), concomitant medications, co-administered food and the specific nature of the condition being treated [see Dosage and Administration (2.3), Warnings and Precautions (5), and Drug Interactions (7)] . Dosing must be individualized to account for these factors and dosage adjustments made based on periodic assessment of the patient's clinical response and laboratory parameters [see Dosage and Administration (2.4)] . For adult patients with primary hypothyroidism, titrate until the patient is clinically euthyroid and the serum TSH returns to normal [see Dosage and Administration (2.3)] . For secondary or tertiary hypothyroidism, serum TSH is not a reliable measure of levothyroxine sodium tablets dosage adequacy and should not be used to monitor therapy. Use the serum free-T4 level to titrate levothyroxine sodium tablets dosing until the patient is clinically euthyroid and the serum free-T4 level is restored to the upper half of the normal range [ see Dosage and Administration (2.3) ]. The peak therapeutic effect of a given dose of levothyroxine sodium tablets may not be attained for 4 to 6 weeks. 2.3 Recommended Dosage and Titration Primary, Secondary, and Tertiary Hypothyroidism in Adults The recommended starting daily dosage of levothyroxine sodium tablets in adults with primary, secondary, or tertiary hypothyroidism is based on age and comorbid cardiac conditions, as described in Table 1. For patients at risk of atrial fibrillation or patients with underlying cardiac disease, start with a lower dosage and titrate the dosage more slowly to avoid exacerbation of cardiac symptoms. Dosage titration is based on serum TSH or free-T4 [ see Dosage and Administration (2.2) ]. Table 1. Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Adults* * Dosages greater than 200 mcg/day are seldom required. An inadequate response to daily dosages greater than 300 mcg/day is rare and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors. [see Dosage and Administration (2.1) and Drug Interactions (7)]. Patient Population Starting Dosage Dosage Titration Based on Serum TSH or Free-T4 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) Primary, Secondary and Tertiary Hypothyroidism in Pediatric Patients The recommended starting daily dosage of levothyroxine sodium tablets in pediatric patients with primary, secondary, or tertiary hypothyroidism is based on body weight and changes with age as described in Table 2. Titrate the dosage (every 2 weeks) as needed based on serum TSH or free-T4 until the patient is euthyroid [see Dosage and Administration (2.2)] . Table 2. Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Pediatric Patients a Adjust dosage based on clinical response and laboratory parameters [see Dosage and Administration (2.4) and Use in Specific Populations (8.4)]. Age Starting Daily Dosage Per Kg Body Weight a 0 to 3 months 10 to 15 mcg/kg/day 3 to 6 months 8 to 10 mcg/kg/day 6 to 12 months 6 to 8 mcg/kg/day 1 to 5 years 5 to 6 mcg/kg/day 6 to 12 years 4 to 5 mcg/kg/day Greater than 12 years but growth and puberty incomplete 2 to 3 mcg/kg/day Growth and puberty complete 1.6 mcg/kg/day Pediatric Patients from Birth to 3 Months of Age at Risk for Cardiac Failure. Start at a lower starting dosage and increase the dosage every 4 to 6 weeks as needed based on clinical and laboratory response. Pediatric Patients at Risk for Hyperactivity To minimize the risk of hyperactivity, start at one-fourth the recommended full replacement dosage, and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached. Hypothyroidism in Pregnant Patients For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at minimum, during each trimester of pregnancy. In pregnant patients with primary hypothyroidism, maintain serum TSH in the trimester-specific reference range. The recommended daily dosage of levothyroxine sodium tablets in pregnant patients is described in Table 3. Table 3. Levothyroxine Sodium Tablets Dosing guidelines for Hypothyroidism in Pregnant Patients Patient Population Starting Dosage Dose Adjustment and Titration Pre-existing primary hypothyroidism with serum TSH above normal trimester- specific range Pre-pregnancy dosage may increase during pregnancy Increase levothyroxine sodium tablet 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 levothyroxine sodium tablet dosage to pre-pregnancy levels immediately after delivery. Monitor serum TSH 4 to 8 weeks postpartum. New onset hypothyroidism (TSH ≥ 10 IU per liter) 1.6 mcg/kg/day Monitor serum TSH every 4 weeks and adjust levothyroxine sodium tablet dosage until serum TSH is within normal trimester-specific range. New onset hypothyroidism (TSH < 10 IU per liter) 1.0 mcg/kg/day TSH Suppression in Well-differentiated Thyroid Cancer in Adult and Pediatric Patients The levothyroxine sodium tablets dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer. 2.4 Monitoring TSH and/or Thyroxine (T4) Levels Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation. Persistent clinical and laboratory evidence of hypothyroidism despite an apparent adequate replacement dose of levothyroxine sodium tablets may be evidence of inadequate absorption, poor compliance, drug interactions, or a combination of these factors. Adults In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage. In patients on a stable and appropriate replacement dosage, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient's clinical status. Pediatric Patients In patients with hypothyroidism, assess the adequacy of replacement therapy by measuring both serum TSH and total or free-T4. Monitor TSH and total or free-T4 in pediatric patients as follows: 2 and 4 weeks after the initiation of treatment, 2 weeks after any change in dosage, and then every 3 to 12 months thereafter following dosage stabilization until growth is completed. Poor compliance or abnormal values may necessitate more frequent monitoring. Perform routine clinical examination, including assessment of development, mental and physical growth, and bone maturation, at regular intervals. The general aim of therapy is to normalize the serum TSH level. TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Failure of the serum T4 to increase into the upper half of the normal range within 2 weeks of initiation of levothyroxine sodium tablets therapy and/or of the serum TSH to decrease below 20 IU per liter within 4 weeks may indicate the patient is not receiving adequate therapy. Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of levothyroxine sodium tablets [see Warnings and Precautions (5.1) and Use in Specific Populations (8.4)] . Secondary and Tertiary Hypothyroidism Monitor serum free-T4 levels and maintain in the upper half of the normal range in these patients.

Indications And Usage

1 INDICATIONS AND USAGE Hypothyroidism Levothyroxine sodium tablets are 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 Levothyroxine sodium tablets are 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 . Limitations of Use Levothyroxine sodium tablets are 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 levothyroxine sodium tablets may induce hyperthyroidism [see Warnings and Precautions ( 5.1 )] . Levothyroxine sodium tablets are not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis. Levothyroxine sodium tablet is a 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. Not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis.

Overdosage

10 OVERDOSAGE The signs and symptoms of overdosage are those of hyperthyroidism [see Warnings and Precautions (5) and Adverse Reactions (6)] . In addition, confusion and disorientation may occur. Cerebral embolism, shock, coma, and death have been reported. Seizures occurred in a 3-year old child ingesting 3.6 mg of levothyroxine. Symptoms may not necessarily be evident or may not appear until several days after ingestion of levothyroxine sodium. Reduce the levothyroxine sodium tablets dosage or discontinue temporarily if signs or symptoms of overdosage occur. Initiate appropriate supportive treatment as dictated by the patient's medical status. For current information on the management of poisoning or overdosage, contact the National Poison Control Center at 1-800-222-1222 or www.poison.org.

Drug Interactions

7 DRUG INTERACTIONS See full prescribing information for drugs that affect thyroid hormone pharmacokinetics and metabolism (e.g., absorption, synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to levothyroxine sodium tablets. ( 7 ) 7.1 Drugs Known to Affect Thyroid Hormone Pharmacokinetics Many drugs can exert effects on thyroid hormone pharmacokinetics and metabolism (e.g., absorption, synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to levothyroxine sodium tablets (Tables 5 to 8). Table 5. Drugs That May Decrease T4 Absorption (Hypothyroidism) Potential impact: Concurrent use may reduce the efficacy of levothyroxine sodium tablets 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 levothyroxine sodium tablets at least 4 hours apart from these agents. Orlistat Monitor patients treated concomitantly with orlistat and levothyroxine sodium tablets for changes in thyroid function. Bile Acid Sequestrants (e.g., colesevelam, cholestyramine, colestipol) Ion Exchange Resins (e.g., Kayexalate) Bile acid sequestrants and ion exchange resins are known to decrease levothyroxine absorption. Administer levothyroxine sodium tablets at least 4 hours prior to these drugs or monitor TSH levels. 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. Table 6. Drugs That May Alter T4 and Triiodothyronine (T3) Serum Transport Without Affecting Free Thyroxine (FT4) Concentration (Euthyroidism) 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 levothyroxine sodium tablets 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 Non-Steroidal Anti-inflammatory Drugs -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 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. Table 7. 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 levothyroxine sodium tablets 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. Table 8. 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 (e.g., 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 (e.g., 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. 7.2 Antidiabetic Therapy Addition of levothyroxine sodium tablets therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control, especially when thyroid therapy is started, changed, or discontinued [see Warnings and Precautions (5.5)] . 7.3 Oral Anticoagulants Levothyroxine sodium tablet increases the response to oral anticoagulant therapy. Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the levothyroxine sodium tablets dose is increased. Closely monitor coagulation tests to permit appropriate and timely dosage adjustments. 7.4 Digitalis Glycosides Levothyroxine sodium tablets may reduce the therapeutic effects of digitalis glycosides. Serum digitalis glycoside levels may decrease when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides. 7.5 Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine sodium tablets may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines. Toxic effects may include increased risk of cardiac arrhythmias and central nervous system stimulation. Levothyroxine sodium tablets may accelerate the onset of action of tricyclics. Administration of sertraline in patients stabilized on levothyroxine sodium tablets may result in increased levothyroxine sodium tablets requirements. 7.6 Ketamine Concurrent use of ketamine and levothyroxine sodium tablets may produce marked hypertension and tachycardia. Closely monitor blood pressure and heart rate in these patients. 7.7 Sympathomimetics Concurrent use of sympathomimetics and levothyroxine sodium tablets may increase the effects of sympathomimetics or thyroid hormone. Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents are administered to patients with coronary artery disease. 7.8 Tyrosine-Kinase Inhibitors Concurrent use of tyrosine-kinase inhibitors such as imatinib may cause hypothyroidism. Closely monitor TSH levels in such patients. 7.9 Drug-Food Interactions Consumption of certain foods may affect levothyroxine sodium tablets absorption thereby necessitating adjustments in dosing [see Dosage and Administration (2.1)] . Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of levothyroxine sodium tablets from the gastrointestinal tract. Grapefruit juice may delay the absorption of levothyroxine and reduce its bioavailability. 7.10 Drug-Laboratory Test Interactions Consider changes in TBG concentration when interpreting T4 and T3 values. Measure and evaluate unbound (free) hormone and/or determine the free-T4 index (FT4I) in this circumstance. Pregnancy, infectious hepatitis, estrogens, estrogen-containing oral contraceptives, and acute intermittent porphyria increase TBG concentration. Nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, androgens, and corticosteroids decrease TBG concentration. Familial hyper- or hypo-thyroxine binding globulinemias have been described, with the incidence of TBG deficiency approximating 1 in 9000.

Drug Interactions Table

Table 5. Drugs That May Decrease T4 Absorption (Hypothyroidism)
Potential impact: Concurrent use may reduce the efficacy of levothyroxine sodium tablets 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 levothyroxine sodium tablets at least 4 hours apart from these agents.
Orlistat Monitor patients treated concomitantly with orlistat and levothyroxine sodium tablets for changes in thyroid function.
Bile Acid Sequestrants (e.g., colesevelam, cholestyramine, colestipol) Ion Exchange Resins (e.g., Kayexalate) Bile acid sequestrants and ion exchange resins are known to decrease levothyroxine absorption. Administer levothyroxine sodium tablets at least 4 hours prior to these drugs or monitor TSH levels.
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.

Clinical Pharmacology

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Thyroid hormones exert their physiologic actions through control of DNA transcription and protein synthesis. Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins. The physiological actions of thyroid hormones are produced predominantly by T3, the majority of which (approximately 80%) is derived from T4 by deiodination in peripheral tissues. 12.2 Pharmacodynamics Oral levothyroxine sodium is a synthetic T4 hormone that exerts the same physiologic effect as endogenous T4, thereby maintaining normal T4 levels when a deficiency is present. 12.3 Pharmacokinetics Absorption Absorption of orally administered T4 from the gastrointestinal tract ranges from 40% to 80%. The majority of the levothyroxine sodium tablets dose is absorbed from the jejunum and upper ileum. The relative bioavailability of levothyroxine sodium tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%. T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybeans. Dietary fiber decreases bioavailability of T4. Absorption may also decrease with age. In addition, many drugs and foods affect T4 absorption [see Drug Interactions (7)] . Distribution Circulating thyroid hormones are greater than 99% bound to plasma proteins, including thyroxine-binding globulin (TBG), thyroxine-binding prealbumin (TBPA), and albumin (TBA), whose capacities and affinities vary for each hormone. The higher affinity of both TBG and TBPA for T4 partially explains the higher serum levels, slower metabolic clearance, and longer half-life of T4 compared to T3. Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone. Only unbound hormone is metabolically active. Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins [see Drug Interactions (7)] . Thyroid hormones do not readily cross the placental barrier [see Use in Specific Populations (8.1)] . Elimination Metabolism T4 is slowly eliminated (see Table 10). The major pathway of thyroid hormone metabolism is through sequential deiodination. Approximately 80% of circulating T3 is derived from peripheral T4 by monodeiodination. The liver is the major site of degradation for both T4 and T3, with T4 deiodination also occurring at a number of additional sites, including the kidney and other tissues. Approximately 80% of the daily dose of T4 is deiodinated to yield equal amounts of T3 and reverse T3 (rT3). T3 and rT3 are further deiodinated to diiodothyronine. Thyroid hormones are also metabolized via conjugation with glucuronides and sulfates and excreted directly into the bile and gut where they undergo enterohepatic recirculation. Excretion Thyroid hormones are primarily eliminated by the kidneys. A portion of the conjugated hormone reaches the colon unchanged and is eliminated in the feces. Approximately 20% of T4 is eliminated in the stool. Urinary excretion of T4 decreases with age. Table 10. Pharmacokinetic Parameters of Thyroid Hormones in Euthyroid Patients Hormone Ratio in Thyroglobulin Biologic Potency t1/2 (days) Protein Binding (%)a Levothyroxine (T4) 10 to 20 1 6 to 7b 99.96 Liothyronine (T3) 1 4 ≤ 2 99.5

Clinical Pharmacology Table

Table 10. Pharmacokinetic Parameters of Thyroid Hormones in Euthyroid Patients
Hormone Ratio in Thyroglobulin Biologic Potency t1/2 (days) Protein Binding (%)a
Levothyroxine (T4) 10 to 20 1 6 to 7b 99.96
Liothyronine (T3) 1 4 ≤ 2 99.5

Mechanism Of Action

12.1 Mechanism of Action Thyroid hormones exert their physiologic actions through control of DNA transcription and protein synthesis. Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins. The physiological actions of thyroid hormones are produced predominantly by T3, the majority of which (approximately 80%) is derived from T4 by deiodination in peripheral tissues.

Pharmacodynamics

12.2 Pharmacodynamics Oral levothyroxine sodium is a synthetic T4 hormone that exerts the same physiologic effect as endogenous T4, thereby maintaining normal T4 levels when a deficiency is present.

Pharmacokinetics

12.3 Pharmacokinetics Absorption Absorption of orally administered T4 from the gastrointestinal tract ranges from 40% to 80%. The majority of the levothyroxine sodium tablets dose is absorbed from the jejunum and upper ileum. The relative bioavailability of levothyroxine sodium tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%. T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybeans. Dietary fiber decreases bioavailability of T4. Absorption may also decrease with age. In addition, many drugs and foods affect T4 absorption [see Drug Interactions (7)] . Distribution Circulating thyroid hormones are greater than 99% bound to plasma proteins, including thyroxine-binding globulin (TBG), thyroxine-binding prealbumin (TBPA), and albumin (TBA), whose capacities and affinities vary for each hormone. The higher affinity of both TBG and TBPA for T4 partially explains the higher serum levels, slower metabolic clearance, and longer half-life of T4 compared to T3. Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone. Only unbound hormone is metabolically active. Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins [see Drug Interactions (7)] . Thyroid hormones do not readily cross the placental barrier [see Use in Specific Populations (8.1)] . Elimination Metabolism T4 is slowly eliminated (see Table 10). The major pathway of thyroid hormone metabolism is through sequential deiodination. Approximately 80% of circulating T3 is derived from peripheral T4 by monodeiodination. The liver is the major site of degradation for both T4 and T3, with T4 deiodination also occurring at a number of additional sites, including the kidney and other tissues. Approximately 80% of the daily dose of T4 is deiodinated to yield equal amounts of T3 and reverse T3 (rT3). T3 and rT3 are further deiodinated to diiodothyronine. Thyroid hormones are also metabolized via conjugation with glucuronides and sulfates and excreted directly into the bile and gut where they undergo enterohepatic recirculation. Excretion Thyroid hormones are primarily eliminated by the kidneys. A portion of the conjugated hormone reaches the colon unchanged and is eliminated in the feces. Approximately 20% of T4 is eliminated in the stool. Urinary excretion of T4 decreases with age. Table 10. Pharmacokinetic Parameters of Thyroid Hormones in Euthyroid Patients Hormone Ratio in Thyroglobulin Biologic Potency t1/2 (days) Protein Binding (%)a Levothyroxine (T4) 10 to 20 1 6 to 7b 99.96 Liothyronine (T3) 1 4 ≤ 2 99.5

Pharmacokinetics Table

Table 10. Pharmacokinetic Parameters of Thyroid Hormones in Euthyroid Patients
Hormone Ratio in Thyroglobulin Biologic Potency t1/2 (days) Protein Binding (%)a
Levothyroxine (T4) 10 to 20 1 6 to 7b 99.96
Liothyronine (T3) 1 4 ≤ 2 99.5

Effective Time

20231108

Version

11

Description Table

Strength (mcg) Color additive(s)
25 FD&C Yellow No. 6 Aluminum Lake*
50 FD&C Blue 1 Aluminum Lake
75 FD&C Red No. 40 Aluminum Lake, FD&C Blue No. 2 Aluminum Lake
88 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, D&C Yellow No. 10 Aluminum Lake
100 FD&C Yellow No. 6 Aluminum Lake*, D&C Yellow No. 10 Aluminum Lake
112 D&C Red No. 27 Aluminum Lake
125 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, FD&C Red No. 40 Aluminum Lake, FD&C Blue No. 2 Aluminum Lake
137 FD&C Blue No. 1 Aluminum Lake
150 FD&C Blue No. 2 Aluminum Lake
175 FD&C Blue No. 1 Aluminum Lake, D&C Red No. 27 Aluminum Lake
200 FD&C Red No. 40 Aluminum Lake
300 FD&C Yellow No. 6 Aluminum Lake*, FD&C Blue No. 1 Aluminum Lake, D&C Yellow No. 10 Aluminum Lake
*Note – FD&C Yellow No. 6 Aluminum Lake is peach in color.

Dosage And Administration Table

Table 1. Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Adults*

* Dosages greater than 200 mcg/day are seldom required. An inadequate response to daily dosages greater than 300 mcg/day is rare and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors. [see Dosage and Administration (2.1) and Drug Interactions (7)].

Patient Population Starting Dosage Dosage Titration Based on Serum TSH or Free-T4
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)

Dosage Forms And Strengths

3 DOSAGE FORMS AND STRENGTHS Levothyroxine sodium tablets USP are round, colored, scored and debossed with following debossing details on one side and break-line on other side. They are available as follows (Table 4) Table 4: Levothyroxine Sodium Tablet Strengths and Identifying Features Tablet Strength Tablet Color/Shape Debossing Details 25 mcg Peach/Round L15 50 mcg White/Round L16 75 mcg Violet/Round L17 88 mcg Olive/Round L19 100 mcg Yellow/Round L20 112 mcg Rose/Round L21 125 mcg Tan/Round L22 137 mcg Turquoise/Round L23 150 mcg Blue/Round L24 175 mcg Lilac/Round L25 200 mcg Pink/Round L26 300 mcg Green/Round L27 Tablets: 25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200, and 300 mcg ( 3 )

Dosage Forms And Strengths Table

Table 4: Levothyroxine Sodium Tablet Strengths and Identifying Features
Tablet Strength Tablet Color/Shape Debossing Details
25 mcg Peach/Round L15
50 mcg White/Round L16
75 mcg Violet/Round L17
88 mcg Olive/Round L19
100 mcg Yellow/Round L20
112 mcg Rose/Round L21
125 mcg Tan/Round L22
137 mcg Turquoise/Round L23
150 mcg Blue/Round L24
175 mcg Lilac/Round L25
200 mcg Pink/Round L26
300 mcg Green/Round L27

Spl Product Data Elements

Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C YELLOW NO. 6 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Peach L15 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C BLUE NO. 1 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L16 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C BLUE NO. 2 FD&C RED NO. 40 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Violet L17 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM D&C YELLOW NO. 10 FD&C BLUE NO. 1 FD&C YELLOW NO. 6 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Olive L19 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM D&C YELLOW NO. 10 FD&C YELLOW NO. 6 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L20 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM D&C RED NO. 27 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Rose L21 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C BLUE NO. 1 FD&C BLUE NO. 2 FD&C RED NO. 40 FD&C YELLOW NO. 6 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Tan L22 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C BLUE NO. 1 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L23 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C BLUE NO. 2 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L24 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM D&C RED NO. 27 FD&C BLUE NO. 1 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN Lilac L25 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM FD&C RED NO. 40 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L26 Levothyroxine Sodium Levothyroxine Sodium LEVOTHYROXINE SODIUM LEVOTHYROXINE LEVOTHYROXINE SODIUM ANHYDROUS CROSCARMELLOSE SODIUM D&C YELLOW NO. 10 FD&C BLUE NO. 1 FD&C YELLOW NO. 6 MAGNESIUM STEARATE MANNITOL SODIUM BICARBONATE STARCH, CORN L27

Carcinogenesis And Mutagenesis And Impairment Of Fertility

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term carcinogenicity studies in animals to evaluate the carcinogenic potential of levothyroxine have not been performed. Studies to evaluate mutagenic potential and animal fertility have not been performed.

Nonclinical Toxicology

13 NONCLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term carcinogenicity studies in animals to evaluate the carcinogenic potential of levothyroxine have not been performed. Studies to evaluate mutagenic potential and animal fertility have not been performed.

Application Number

ANDA209713

Brand Name

Levothyroxine Sodium

Generic Name

Levothyroxine Sodium

Product Ndc

68180-973

Product Type

HUMAN PRESCRIPTION DRUG

Route

ORAL

Package Label Principal Display Panel

PACKAGE LABEL.PRINCIPAL DISPLAY PANEL Levothyroxine Sodium Tablets USP Rx Only 25 mcg NDC 68180-965-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 50 mcg NDC 68180-966-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 75 mcg NDC 68180-967-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 88 mcg NDC 68180-968-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 100 mcg NDC 68180-969-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 112 mcg NDC 68180-970-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 125 mcg NDC 68180-971-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 137 mcg NDC 68180-972-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 150 mcg NDC 68180-973-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 175 mcg NDC 68180-974-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 200 mcg NDC 68180-975-01 100's Tablets Levothyroxine Sodium Tablets USP Rx Only 300 mcg NDC 68180-976-01 100's Tablets image-2 image-3 image-4 image-5 image-6 image-7 image-8 image-9 image-10 image-11 image-12 image-13

Recent Major Changes

RECENT MAJOR CHANGES Indications and Usage (1) 8/2022 Dosage and Administration (2.2) 8/2022 Dosage and Administration (2.3) 8/2022 Warnings and Precautions (5.1) 8/2022 Warnings and Precautions (5.4) 8/2022

Information For Patients

17 PATIENT COUNSELING INFORMATION Inform the patient of the following information to aid in the safe and effective use of levothyroxine sodium tablets: Dosing and Administration Instruct patients to take levothyroxine sodium tablets only as directed by their healthcare provider. Instruct patients to take levothyroxine sodium tablets as a single dose, preferably on an empty stomach, one-half to one hour before breakfast. Inform patients that agents such as iron and calcium supplements and antacids can decrease the absorption of levothyroxine. Instruct patients not to take levothyroxine sodium tablets within 4 hours of these agents. Instruct patients to notify their healthcare provider if they are pregnant or breastfeeding or are thinking of becoming pregnant while taking levothyroxine sodium tablets. Important Information Inform patients that it may take several weeks before they notice an improvement in symptoms. Inform patients that the levothyroxine in levothyroxine sodium tablet is intended to replace a hormone that is normally produced by the thyroid gland. Generally, replacement therapy is to be taken for life. Inform patients that levothyroxine sodium tablets should not be used as a primary or adjunctive therapy in a weight control program. Instruct patients to notify their healthcare provider if they are taking any other medications, including prescription and over-the-counter preparations. Instruct patients to notify their physician of any other medical conditions they may have, particularly heart disease, diabetes, clotting disorders, and adrenal or pituitary gland problems, as the dose of medications used to control these other conditions may need to be adjusted while they are taking levothyroxine sodium tablets. If they have diabetes, instruct patients to monitor their blood and/or urinary glucose levels as directed by their physician and immediately report any changes to their physician. If patients are taking anticoagulants, their clotting status should be checked frequently. Instruct patients to notify their physician or dentist that they are taking levothyroxine sodium tablets prior to any surgery. Adverse Reactions Instruct patients to notify their healthcare provider if they experience any of the following symptoms: rapid or irregular heartbeat, chest pain, shortness of breath, leg cramps, headache, nervousness, irritability, sleeplessness, tremors, change in appetite, weight gain or loss, vomiting, diarrhea, excessive sweating, heat intolerance, fever, changes in menstrual periods, hives or skin rash, or any other unusual medical event. Inform patients that partial hair loss may occur rarely during the first few months of levothyroxine sodium tablets therapy, but this is usually temporary. Manufactured for: Lupin Pharmaceuticals, Inc. Baltimore, Maryland 21202 United States Manufactured by: Lupin Limited Pithampur (M.P.) - 454 775 INDIA Revised: September 2023 ID#: 274663

Geriatric Use

8.5 Geriatric Use Because of the increased prevalence of cardiovascular disease among the elderly, initiate levothyroxine sodium tablets at less than the full replacement dose [see Dosage and Administration (2.3) and Warnings and Precautions (5.2)] . Atrial arrhythmias can occur in elderly patients. Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly.

Pediatric Use

8.4 Pediatric Use Levothyroxine Sodium Tablets is indicated in patients from birth to less than 17 years of age: As a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer. Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on cognitive development as well as on overall physical growth and maturation. Therefore, initiate levothyroxine sodium tablets therapy immediately upon diagnosis. Levothyroxine is generally continued for life in these patients. [see Warnings and Precautions (5.1)] . Closely monitor infants during the first 2 weeks of levothyroxine sodium tablets therapy for cardiac overload and arrhythmias.

Pregnancy

8.1 Pregnancy Risk Summary The clinical experience, including data from postmarketing studies, in pregnant women treated with oral levothyroxine to maintain euthyroid state have not reported increased rates of major birth defects, miscarriages, or other adverse maternal or fetal outcomes. There are risks to the mother and fetus associated with untreated hypothyroidism in pregnancy. Since TSH levels may increase during pregnancy, TSH should be monitored and levothyroxine sodium tablets dosage adjusted during pregnancy ( see Clinical Considerations) . Animal reproductive studies have not been conducted with levothyroxine sodium. Levothyroxine sodium tablets should not be discontinued during pregnancy and hypothyroidism diagnosed during pregnancy should be promptly treated. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Maternal hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, gestational hypertension, pre-eclampsia, stillbirth, and premature delivery. Untreated maternal hypothyroidism may have an adverse effect on fetal neurocognitive development. Dose Adjustments During Pregnancy and the Postpartum Period Pregnancy may increase levothyroxine sodium tablets requirements. Serum TSH levels should be monitored and the levothyroxine sodium tablets dosage adjusted during pregnancy. Since postpartum TSH levels are similar to preconception values, the levothyroxine sodium tablets dosage should return to the pre-pregnancy dose immediately after delivery [see Dosage and Administration (2.3)] .

Use In Specific Populations

8 USE IN SPECIFIC POPULATIONS Pregnancy may require the use of higher doses of levothyroxine sodium tablets. ( 2.3 , 8.1 ) 8.1 Pregnancy Risk Summary The clinical experience, including data from postmarketing studies, in pregnant women treated with oral levothyroxine to maintain euthyroid state have not reported increased rates of major birth defects, miscarriages, or other adverse maternal or fetal outcomes. There are risks to the mother and fetus associated with untreated hypothyroidism in pregnancy. Since TSH levels may increase during pregnancy, TSH should be monitored and levothyroxine sodium tablets dosage adjusted during pregnancy ( see Clinical Considerations) . Animal reproductive studies have not been conducted with levothyroxine sodium. Levothyroxine sodium tablets should not be discontinued during pregnancy and hypothyroidism diagnosed during pregnancy should be promptly treated. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Maternal hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, gestational hypertension, pre-eclampsia, stillbirth, and premature delivery. Untreated maternal hypothyroidism may have an adverse effect on fetal neurocognitive development. Dose Adjustments During Pregnancy and the Postpartum Period Pregnancy may increase levothyroxine sodium tablets requirements. Serum TSH levels should be monitored and the levothyroxine sodium tablets dosage adjusted during pregnancy. Since postpartum TSH levels are similar to preconception values, the levothyroxine sodium tablets dosage should return to the pre-pregnancy dose immediately after delivery [see Dosage and Administration (2.3)] . 8.2 Lactation Risk Summary Published studies report that levothyroxine is present in human milk following the administration of oral levothyroxine. No adverse effects on the breastfed infant have been reported and there is no information on the effects of levothyroxine on milk production. Adequate levothyroxine treatment during lactation may normalize milk production in hypothyroid lactating mothers with low milk supply. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for levothyroxine sodium tablets and any potential adverse effects on the breastfed infant from levothyroxine sodium tablets or from the underlying maternal condition. 8.4 Pediatric Use Levothyroxine Sodium Tablets is indicated in patients from birth to less than 17 years of age: As a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer. Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on cognitive development as well as on overall physical growth and maturation. Therefore, initiate levothyroxine sodium tablets therapy immediately upon diagnosis. Levothyroxine is generally continued for life in these patients. [see Warnings and Precautions (5.1)] . Closely monitor infants during the first 2 weeks of levothyroxine sodium tablets therapy for cardiac overload and arrhythmias. 8.5 Geriatric Use Because of the increased prevalence of cardiovascular disease among the elderly, initiate levothyroxine sodium tablets at less than the full replacement dose [see Dosage and Administration (2.3) and Warnings and Precautions (5.2)] . Atrial arrhythmias can occur in elderly patients. Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly.

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING How Supplied Levothyroxine sodium tablets USP are round, colored, scored and debossed with following debossing details on one side and break-line on other side. They are supplied as follows: Strength (mcg) Color/Shape Debossing Details NDC# for bottles of 90 NDC # for bottles of 100 NDC # for bottles of 500 NDC # for bottles of 1000 25 Peach/Round L15 68180-965-09 68180-965-01 68180-965-02 68180-965-03 50 White/Round L16 68180-966-09 68180-966-01 68180-966-02 68180-966-03 75 Violet/Round L17 68180-967-09 68180-967-01 68180-967-02 68180-967-03 88 Olive/Round L19 68180-968-09 68180-968-01 68180-968-02 68180-968-03 100 Yellow/Round L20 68180-969-09 68180-969-01 68180-969-02 68180-969-03 112 Rose/Round L21 68180-970-09 68180-970-01 68180-970-02 68180-970-03 125 Tan/Round L22 68180-971-09 68180-971-01 68180-971-02 68180-971-03 137 Turquoise/Round L23 68180-972-09 68180-972-01 68180-972-02 68180-972-03 150 Blue/Round L24 68180-973-09 68180-973-01 68180-973-02 68180-973-03 175 Lilac/Round L25 68180-974-09 68180-974-01 68180-974-02 68180-974-03 200 Pink/Round L26 68180-975-09 68180-975-01 68180-975-02 68180-975-03 300 Green/Round L27 68180-976-09 68180-976-01 68180-976-02 68180-976-03 Storage and Handling Store at 25°C (77°F); excursions permitted to 15° to 30° C (59° to 86° F) [see USP Controlled Room Temperature]. Levothyroxine sodium tablets USP should be protected from light and moisture.

How Supplied Table

Strength (mcg) Color/Shape Debossing Details NDC# for bottles of 90 NDC # for bottles of 100 NDC # for bottles of 500 NDC # for bottles of 1000
25 Peach/Round L15 68180-965-09 68180-965-01 68180-965-02 68180-965-03
50 White/Round L16 68180-966-09 68180-966-01 68180-966-02 68180-966-03
75 Violet/Round L17 68180-967-09 68180-967-01 68180-967-02 68180-967-03
88 Olive/Round L19 68180-968-09 68180-968-01 68180-968-02 68180-968-03
100 Yellow/Round L20 68180-969-09 68180-969-01 68180-969-02 68180-969-03
112 Rose/Round L21 68180-970-09 68180-970-01 68180-970-02 68180-970-03
125 Tan/Round L22 68180-971-09 68180-971-01 68180-971-02 68180-971-03
137 Turquoise/Round L23 68180-972-09 68180-972-01 68180-972-02 68180-972-03
150 Blue/Round L24 68180-973-09 68180-973-01 68180-973-02 68180-973-03
175 Lilac/Round L25 68180-974-09 68180-974-01 68180-974-02 68180-974-03
200 Pink/Round L26 68180-975-09 68180-975-01 68180-975-02 68180-975-03
300 Green/Round L27 68180-976-09 68180-976-01 68180-976-02 68180-976-03

Boxed Warning

WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including levothyroxine sodium tablets, 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 levothyroxine sodium tablet 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 ).

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