May 3, 2016
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How Supplied


Levothyroxine sodium is used for the following indications:

Hypothyroidism—As replacement or supplemental therapy in congenital or acquired hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis. Specific indications include: primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) hypothyroidism and subclinical hypothyroidism. Primary hypothyroidism may result from functional deficiency, primary atrophy, partial or total congenital absence of the thyroid gland, or from the effects of surgery, radiation, or drugs, with or without the presence of goiter.

Pituitary TSH Suppression—In the treatment or prevention of various types of euthyroid goiters (see PRECAUTIONS), including thyroid nodules (see PRECAUTIONS), subacute or chronic Iymphocytic thyroiditis (Hashimoto's thyroiditis), multinodular goiter and, as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer.


General Principles:

The goal of replacement therapy is to achieve and maintain a clinical and biochemical euthyroid state. The goal of suppressive therapy is to inhibit growth and/or function of abnormal thyroid tissue. The dose of UNITHROID (levothyroxine sodium) that is adequate to achieve these goals depends on a variety of factors including the patient's age, body weight, cardiovascular status, concomitant medical conditions, including pregnancy, concomitant medications, and the specific nature of the condition being treated (see PRECAUTIONS). Hence, the following recommendations serve only as dosing guidelines. Dosing must be individualized and adjustments made based on periodic assessment of the patient's clinical response and laboratory parameters (see PRECAUTIONS, Laboratory Tests).

UNITHROID (levothyroxine sodium) is administered as a single daily dose, preferably one-half to one-hour before breakfast. UNITHROID (levothyroxine sodium) should be taken at least 4 hours apart from drugs that are known to interfere with its absorption (see PRECAUTIONS, Drug Interactions).

Due to the long half-life of levothyroxine, the peak therapeutic effect at a given dose of levothyroxine may not be attained for 4-6 weeks.

Caution should be exercised when administering UNITHROID (levothyroxine sodium) to patients with underlying cardiovascular disease, to the elderly, and to those with concomitant adrenal insufficiency (see PRECAUTIONS).

Specific Patient Populations:

Hypothyroidism in Adults and in Children in Whom Growth and Puberty are Complete (see PRECAUTIONS, Laboratory Tests).

Therapy may begin at full replacement doses in otherwise healthy individuals less than 50 years old and in those older than 50 years who have been recently treated for hyperthyroidism or who have been hypothyroid for only a short time (such as a few months). The average full replacement dose of levothyroxine is approximately 1.7 mcg/kg/day (e.g., 100-125 mcg/day for a 70 kg adult). Older patients may require less than 1 mcg/kg/day. Levothyroxine doses greater than 200 mcg/day are seldom required. An inadequate response to daily doses ≥ 300 mcg/day is rare and may indicate poor compliance, malabsorption, and/or drug interactions.

For most patients older than 50 years or for patients under 50 years of age with underlying cardiac disease, an initial starting dose of 25-50 mcg/day of levothyroxine is recommended, with gradual increments in dose at 6-8 week intervals. The recommended starting dose of levothyroxine in elderly patients with cardiac disease is 12.5-25 mcg/day, with gradual dose increments at 4-6 week intervals. The levothyroxine dose is generally adjusted in 12.5-25 mcg increments until the patient with primary hypothyroidism is clinically euthyroid and the serum TSH has normalized.

In patients with severe hypothyroidism, the recommended initial levothyroxine dose is 12.5-25 mcg/day with increases of 25 mcg/day every 2-4 weeks, accompanied by clinical and laboratory assessment, until the TSH level is normalized.

In patients with secondary (pituitary) or tertiary (hypothalamic) hypothyroidism, the levothyroxine dose should be titrated 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 (see PRECAUTIONS, Laboratory Tests)

General Principles

In general, levothyroxine therapy should be instituted at full replacement doses as soon as possible. Delays in diagnosis and institution of therapy may have deleterious effects on the child's intellectual and physical growth and development.

Undertreatment and overtreatment should be avoided (see PRECAUTIONS, Pediatric Use). UNITHROID (levothyroxine sodium) may be administered to infants and children who cannot swallow intact tablets by crushing the tablet and suspending the freshly crushed tablet in a small amount (5-10 mL or 1-2 teaspoons) of water. This suspension can be administered by spoon or dropper.


Foods that decrease absorption of levothyroxine such as soybean infant formula, should not be used for administering levothyroxine. (see PRECAUTIONS, Drug-Food Interactions).


The recommended starting dose of levothyroxine in newborn infants is 10-15 mcg/kg/day. A lower starting dose (e.g., 25 mcg/day) should be considered in infants at risk for cardiac failure, and the dose should be increased in 4-6 weeks as needed based on clinical and laboratory response to treatment. In infants with very low (< 5 mcg/dl) or undetectable serum T4 concentrations, the recommended initial starting dose is 50 mcg/day of levothyroxine.

Infants and Children

Levothyroxine therapy is usually initiated at full replacement doses, with the recommended dose per body weight decreasing with age (see TABLE 3). However, in children with chronic or severe hypothyroidism, an initial dose of 25 mcg/day of levothyroxine is recommended with increments of 25 mcg every 2-4 weeks until the desired effect is achieved.

Hyperactivity in an older child can be minimized if the starting dose is one-fourth of the recommended full replacement dose, and the dose is then increased on a weekly basis by an amount equal to one-fourth the full recommended replacement dose until the full recommended replacement dose is reached.

Table 3: Levothyroxine Dosing Guidelines for Pediatric Hypothyroidism


Daily Dose Per Kg Body Weighta

0-3 months

10-15 mcg/kg/day

3-6 months

8-10 mcg/kg/day

6-12 months

6-8 mcg/kg/day

1-5 years

5-6 mcg/kg/day

6-12 years

4-5 mcg/kg/day

>12 years

2-3 mcg/kg/day

Growth and puberty complete

1.7 mcg/kg/day

a The dose should be adjusted based on clinical response and laboratory parameters (see PRECAUTlONS, Laboratory Tests and Pediatric Use).

Pregnancy—Pregnancy may increase levothyroxine requirements (see PREGNANCY). Subclinical Hypothyroidism—If this condition is treated, lower levothyroxine doses (e.g. 1 mcg/kg/day) than that used for full replacement may be adequate to normalize the serum TSH level. Patients who are not treated should be monitored yearly for changes in clinical status and thyroid laboratory parameters.

TSH Suppression in Well-differentiated Thyroid Cancer and Thyroid Nodules—

Levothyroxine is used as an adjunct to surgery and radioiodine therapy in the treatment of well-differentiated (papillary and follicular) thyroid cancer. Generally, TSH is suppressed to <0.1 mU/L, and this usually requires a levothyroxine dose of greater than 2 mcg/kg/day. In the treatment of benign nodules and nontoxic multinodular goiter, TSH is generally suppressed to a higher target (0.1-0.3 mU/L) than that used for the treatment of thyroid cancer. Exercise caution when administering levothyroxine to patients with autonomous thyroid tissue (see PRECAUTIONS).

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. Therefore, oral levothyroxine is not recommended to treat this condition. Intravenous levothyroxine sodium should be administered.


UNITHROID™ (levothyroxine sodium tablets, USP ) are round, color coded, partial bisected tablets debossed with JSP and ID Number:

Strength (mcg)


NDC# for bottles of 100

NDC# for bottles of 1000



NDC 52544-902-01

NDC 52544-902-10



NDC 52544-903-01

NDC 52544-903-10



NDC 52544-904-01

NDC 52544-904-10



NDC 52544-905-01

NDC 52544-905-10



NDC 52544-906-01

NDC 52544-906-10



NDC 52544-907-01

NDC 52544-907-10



NDC 52544-908-01

NDC 52544-908-10



NDC 52544-909-01

NDC 52544-909-10



NDC 52544-910-01

NDC 52544-910-10



NDC 52544-911-01

NDC 52544-911-10



NDC 52544-912-01

NDC 52544-912-10


20°C to 25°C (68°F to 77° F) with excursions between 15°C to 30°C (59°F to 86° F)

Manufactured for: Watson Pharma, Inc.,A Subsidiary of Watson Laboratories, Inc.

Corona, CA 92880

Manufactured by: Jerome Stevens Pharmaceuticals, Inc., Bohemia, NY 11716

Rev. 10/00

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 3/10/2008

How Supplied

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