Levothyroxine Sodium: Package Insert and Label Information

LEVOTHYROXINE SODIUM- levothyroxine sodium capsule
Lannett Company, Inc.

WARNING: NOT FOR TREATMENT OF OBESITY or FOR WEIGHT LOSS

  • Thyroid hormones, including Levothyroxine Sodium capsules, 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)].

1 INDICATION AND USAGE

Hypothyroidism

Levothyroxine Sodium capsules are indicated as a replacement therapy in adults and pediatric patients 6 years and older with primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.

Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) Suppression

Levothyroxine Sodium capsules are indicated as an adjunct to surgery and radioiodine therapy in the management of adults and pediatric patients 6 years and older with thyrotropin-dependent well-differentiated thyroid cancer.

Limitations of Use:

  • Levothyroxine Sodium capsules 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 capsules may induce hyperthyroidism [see Warnings and Precautions (5.4)].
  • Levothyroxine Sodium capsules are not indicated for treatment of transient hypothyroidism during the recovery phase of subacute thyroiditis.

2 DOSAGE AND ADMINISTRATION

2.1 General Administration Information

Administer Levothyroxine Sodium capsules as a single daily oral dose, on an empty stomach, one-half to one hour before breakfast.

Administer Levothyroxine Sodium capsules at least 4 hours before or after drugs known to interfere with Levothyroxine Sodium capsules absorption [see Drug Interactions (7.1)]

Evaluate the need for dose adjustments when regularly administering within an hour of certain foods that may affect Levothyroxine Sodium capsules absorption [see Drug Interactions (7.9) and Clinical Pharmacology (12.3)].

Swallow Levothyroxine Sodium capsules whole, do not cut, crush, or chew.

2.2 General Principles of Dosing

The dose of Levothyroxine Sodium capsules 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 capsules 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 capsules at the full replacement dose in otherwise healthy, non-elderly individuals who have been hypothyroid for only a short time (such as a few months).The average full replacement dose of Levothyroxine Sodium capsules are approximately 1.6 mcg per kg per day (for example: 100-125 mcg per day for a 70 kg adult).

Adjust the dose by 12.5 to 25 mcg increments every 4 to 6 weeks until the patient is clinically euthyroid and the serum TSH returns to normal. Doses greater than 200 mcg per day are seldom required. An inadequate response to daily doses greater than 300 mcg per day is rare and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors.

For elderly patients or patients with underlying cardiovascular disease, start with a dose of 12.5 to 25 mcg per day. Increase the dose every 6 to 8 weeks, as needed, until the patient is clinically euthyroid and the serum TSH returns to normal. The full replacement dose of Levothyroxine Sodium capsules may be less than 1 mcg per kg per day in elderly patients.

In patients with severe longstanding hypothyroidism, start with a dose of 12.5 to 25 mcg per day. Adjust the dose in 12.5 to 25 mcg increments every 2 to 4 weeks until the patient is clinically euthyroid and the serum TSH level is normalized.

Secondary or Tertiary Hypothyroidism

Start Levothyroxine Sodium capsules at the full replacement dose in otherwise healthy, non-elderly individuals. Start with a lower dose in elderly patients with underlying cardiovascular disease or patients with severe longstanding hypothyroidism as described above. Serum TSH is not a reliable measure of Levothyroxine Sodium capsules dose adequacy in patients with secondary or tertiary hypothyroidism, and should not be used to monitor therapy. Use the serum free-T4 level to monitor adequacy of therapy in this patient population. Titrate Levothyroxine Sodium capsules dosing per above instructions until the patient is clinically euthyroid and the serum free-T4 level is restored to the upper half of the normal range.

Pediatric Dosage — Congenital or Acquired Hypothyroidism

Only administer Levothyroxine Sodium capsules to pediatric patients 6 years and older who are able to swallow an intact capsule.

The recommended daily dose of Levothyroxine Sodium capsules in pediatric patients with hypothyroidism is based on body weight and changes with age as described in Table 1. Start Levothyroxine Sodium capsules at the full daily dose in most pediatric patients. Start at a lower dose in children at risk for hyperactivity (see below). Monitor for clinical and laboratory response [see Dosage and Administration (2.4)].

Table 1: Levothyroxine Sodium Capsules Dosing Guidelines for Pediatric Hypothyroidism
Age Daily Dose Per Kg Body Weight *
*
The dose should be adjusted based on clinical response and laboratory parameters [see Dosage and Administration (2.4) and Use in Specific Populations (8.4)].
6-12 years 4-5 mcg/kg/day
Greater than 12 years but growth and puberty incomplete 2-3 mcg/kg/day
Growth and puberty complete 1.6 mcg/kg/day

Children at risk for hyperactivity: To minimize the risk of hyperactivity in children, start at one-fourth the recommended full replacement dose, and increase on a weekly basis by one-fourth the full-recommended replacement dose until the full recommended replacement dose is reached.

Pregnancy

Preexisting Hypothyroidism: Levothyroxine Sodium capsules dose requirements may increase during pregnancy. Measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at a minimum, during each trimester of pregnancy. In patients with primary hypothyroidism, maintain serum TSH in the trimester-specific reference range. For patients with serum TSH above the normal trimester specific range, increase the dose of Levothyroxine Sodium capsules by 12.5 to 25 mcg per day and measure TSH every four weeks until a stable Levothyroxine Sodium capsules dose is reached and serum TSH is within the normal trimester specific range. Reduce Levothyroxine Sodium capsules dosage to pre-pregnancy levels immediately after delivery and measure serum TSH levels 4 to 8 weeks postpartum to ensure the Levothyroxine Sodium capsules dose is appropriate.

New Onset Hypothyroidism: Normalize thyroid function as rapidly as possible. In patients with moderate to severe signs and symptoms of hypothyroidism, start Levothyroxine Sodium capsules at the full replacement dose (1.6 mcg per kg body weight per day). In patients with mild hypothyroidism (TSH < 10 mIU per Liter), start Levothyroxine Sodium capsules at 1.0 mcg per kg body weight per day. Evaluate serum TSH every 4 weeks and adjust Levothyroxine Sodium capsules dosage until serum TSH is within the normal trimester specific range [see Use in Specific Populations (8.1)].

TSH Suppression in Well-Differentiated Thyroid Cancer

Generally, TSH is suppressed to below 0.1 mIU per Liter, and this usually requires a Levothyroxine Sodium capsules dose of greater than 2 mcg per kg per day. However, in patients with high-risk tumors, the target level for TSH suppression may be lower.

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 capsules 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 dose. In patients on a stable and appropriate replacement dose, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient’s clinical status.

Pediatrics

In patients with congenital 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 children is as follows: at 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 dose stabilization until growth is completed. Poor compliance or abnormal values may necessitate more frequent monitoring. Perform routine clinical examination, including assessment of mental and physical growth and development, and bone maturation at regular intervals.

While 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 the 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 capsules therapy and/or of the serum TSH to decrease below 20 mIU per Liter within 4 weeks may indicate the child is not receiving adequate therapy. Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of Levothyroxine Sodium capsules [see Warnings and Precautions (5.4) and Use in Specific Populations (8.4)].

Secondary (Pituitary) and Tertiary (Hypothalamic) Hypothyroidism

Monitor serum free-T4 levels maintain in the upper half of the normal range in these patients.

3 DOSAGE FORMS AND STRENGTHS

Levothyroxine Sodium capsules are amber-colored, round/biconvex capsules, imprinted with a dosage strength specific letter on one side and containing a viscous amber-colored liquid and are available as follows:

Strength (mcg) Imprint Code
13 A
25 E
50 G
75 H
88 J
100 K
112 M
125 N
137 P
150 S
175 U
200 Y

4 CONTRAINDICATIONS

Levothyroxine Sodium capsules are contraindicated in patients with uncorrected adrenal insufficiency [see Warnings and Precautions (5.3)].

5 WARNINGS AND PRECAUTIONS

5.1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Overtreatment with levothyroxine may cause an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients. Initiate Levothyroxine Sodium capsules therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease [see Dosage and Administration (2.3) and Use in Specific Populations (8.5)].

Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive Levothyroxine Sodium capsules therapy. Monitor patients receiving concomitant Levothyroxine Sodium capsules and sympathomimetic agents for signs and symptoms of coronary insufficiency. If cardiac symptoms develop or worsen, reduce the Levothyroxine Sodium capsules dose or withhold it for one week and restart at a lower dose.

5.2 Myxedema Coma

Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of levothyroxine sodium from the gastrointestinal tract. Use of oral thyroid hormone drug products is not recommended to treat myxedema coma. Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma.

5.3 Acute Adrenal Crisis in Patients with Concomitant Adrenal Insufficiency

Thyroid hormone increases metabolic clearance of glucocorticoids. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy precipitate an acute adrenal crisis in patient with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with Levothyroxine Sodium capsules [see Contraindications (4)].

5.4 Prevention of Hyperthyroidism or Incomplete Treatment of Hypothyroidism

Levothyroxine Sodium capsules have a narrow therapeutic index. Over- or under-treatment with Levothyroxine Sodium capsules may have negative effects on growth and development, cardiovascular function, bone metabolism, reproductive function, cognitive function, emotional state, gastrointestinal function, and on glucose and lipid metabolism. Titrate the dose of Levothyroxine Sodium capsules carefully and monitor response to titration to avoid these effects [see Dosage and Administration (2.4)]. Monitor for the presence of drug or food interactions when using Levothyroxine Sodium capsules and adjust the dose as necessary [see Drug Interactions (7) and Clinical Pharmacology (12.3)].

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