Levothyroxine Sodium

FDA Drug Information • Also known as: Ermeza, Euthyrox, Levo-T, Levothyroxine Sodium, Levoxyl, Synthroid, Thyquidity, Tirosint, Tirosint...

Brand Names: Ermeza, Euthyrox, Levo-T, Levothyroxine Sodium, Levoxyl, Synthroid, Thyquidity, Tirosint, Tirosint Sol, Unithroid
Route: ORAL
Dosage Form: TABLET
Product Type: HUMAN PRESCRIPTION DRUG

⚠ Boxed Warning (Black Box)

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 tablets 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).

Description

11 DESCRIPTION Levothyroxine sodium tablets, USP contain synthetic crystalline L-3,3',5,5'- tetraiodothyronine sodium salt [levothyroxine (T4) sodium]. Synthetic T4 is chemically identical to that produced in the human thyroid gland. Levothyroxine (T4) sodium has an empirical formula of C15H10I4NNaO4

xH2O (where x = 5), molecular weight of 798.86 g/mol (anhydrous) and structural formula as shown: Levothyroxine sodium tablets 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 tablet contains the inactive ingredients Magnesium Stearate, NF; Microcrystalline Cellulose, NF; Colloidal Silicone Dioxide, NF; and Sodium Starch Glycolate, NF. Each tablet strength meets USP Dissolution Test 2. Table 6 provides a listing of the color additives by tablet strength: Table 6. Levothyroxine Sodium Tablets Color Additives Strength (mcg) Color additive(s) 25 FD&C Yellow No. 6 Aluminum Lake 50 None 75 FD&C Blue No. 2 Aluminum Lake, D&C Red No. 27 Aluminum Lake 88 FD&C Blue No. 1 Aluminum Lake, D&C Yellow No. 10 Aluminum Lake, D&C RedNo. 30 Aluminum Lake 100 D&C Yellow No. 10 Aluminum Lake, D&C Red Lake Blend (D&C Red No. 27 Lake and D&C Red No. 30 Lake) 112 D&C Red No. 27 Aluminum Lake, D&C Red No. 30 Aluminum Lake 125 FD&C Yellow No. 6 Aluminum Lake, FD&C Red No. 40 Aluminum Lake, FD&C Blue No. 1 Aluminum Lake 137 FD&C Blue No. 1 Aluminum Lake 150 FD&C Blue No. 2 Aluminum Lake 175 D&C Red No. 27 Aluminum Lake, D&C Red No. 30 Aluminum Lake, FD&C Blue No. 1 Aluminum Lake 200 D&C Yellow No. 10 Aluminum Lake, D&C Red No. 27 Aluminum Lake 300 D&C Yellow No. 10 Aluminum Lake, FD&C Yellow No. 6 Aluminum Lake, FD&C Blue No. 1 Aluminum Lake levothyroixe molecule

What Is Levothyroxine Sodium Used For?

1 INDICATIONS AND USAGE Hypothyroidism Levothyroxine sodium tablets are indicated 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 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 (5.4)].

Levothyroxine sodium tablets are not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis. Levothyroxine sodium tablets is L-thyroxine (T4) indicated 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.

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 4-6 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 General Administration Information Take levothyroxine sodium tablets with a full glass of water as the tablet may rapidly disintegrate. 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 dose adjustments when regularly administering within one hour of certain foods that may affect levothyroxine sodium tablets absorption [see Drug Interactions (7.9) and Clinical Pharmacology (12.3)]. Administer levothyroxine sodium tablets to infants and children who cannot swallow intact tablets by crushing the tablet, suspending the freshly crushed tablet in a small amount (5 to 10 mL or 1 to 2 teaspoons) of water and immediately administering the suspension by spoon or dropper. 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 General Principles of Dosing The dose 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 dose adjustments made based on periodic assessment of the patient's clinical response and laboratory parameters [see Dosage and Administration (2.4)]. The peak therapeutic effect of a given dose of levothyroxine sodium tablets may not be attained for 4 to 6 weeks. 2.3 Dosing in Specific Patient Populations Primary Hypothyroidism in Adults and in Adolescents in Whom Growth and Puberty are Complete Start levothyroxine sodium tablets at the full replacement dose in otherwise healthy, non-elderly individuals who have been hypothyroid for only a short time (such as a few...

Side Effects (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 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 Lannett Company, Inc. at 1-844-834-0530 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . Adverse Reactions in Children Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in children receiving levothyroxine therapy. Overtreatment may result in craniosynostosis in infants and premature closure of the epiphyses in children 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.

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 (see Tables 2-5 below). Table 2. 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 Calcium Carbonate Ferrous Sulfate Calcium carbonate may form an insoluble chelate with levothyroxine, and ferrous sulfate likely forms a ferric-thyroxine complex. 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 -Colesevelam -Cholestyramine -Colestipol Ion Exchange Resins -Kayexalate -Sevelamer 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. Other drugs: Proton Pump Inhibitors Sucralfate Antacids - 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 3. 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...

Contraindications

4 CONTRAINDICATIONS Levothyroxine sodium tablets is contraindicated in patients with uncorrected adrenal insufficiency [see Warnings and Precautions (5.3)] . Uncorrected adrenal insufficiency. (4)

Pregnancy and Breastfeeding

8.1 Pregnancy Risk Summary Experience with levothyroxine use in pregnant women, including data from post-marketing studies, have not reported increased rates of major birth defects or miscarriages [see Data]. 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] . There are no animal studies conducted with levothyroxine during pregnancy. 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. 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 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)]. Data Data Human Data Levothyroxine is approved for use as a replacement therapy for hypothyroidism. There is a long experience of levothyroxine use in pregnant women,...

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 dose 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.

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING Levothyroxine Sodium Tablets, USP are supplied as follows: Strength (mcg) Color/Shape Tablet Markings NDC# for bottles of 30 50 White/ Caplet "50" and "GG/332" 51655-532-52 Storage Conditions 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 should be protected from light and moisture.

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.