SYNTHROID®levothyroxine sodium tablets, USP

Family history is very important when talking to these patients because there is a strong predisposition amongst family members in the primary setting to have another family member with hypothyroidism. One of the difficulties of the diagnosis of hypothyroidism is that the signs and symptoms are non-specific to the disease. So, in order to diagnose the disease accurately, given the non-specific symptoms, you must use the TSH level as a screening tool to assist in the family history and signs and symptoms that you have come across. 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. Monitor patients treated concomitantly with orlistat and levothyroxine sodium tablets for changes in thyroid function.

ADVERSE REACTIONS

Dosage titration is based on serum TSH or free-T4 see Dosage and Administration (2.2) . 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) . TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback.

How is Levothyroxine supplied

Levothyroxine sodium tablets increase 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. The recommended starting daily dosage of SYNTHROID in pediatric patients with primary, secondary, or tertiary hypothyroidism is based on body weight and changes with age as described in Table 2.

  • Occasionally, chronic autoimmune thyroiditis may occur in association with other autoimmune disorders such as adrenal insufficiency, pernicious anemia, and insulin-dependent diabetes mellitus.
  • It also helps your patient pay the lowest possible price for the product you write if it is billed through insurance.
  • 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.
  • In this setting, the clinician should have a high index of suspicion of relapse.
  • Thyroid hormones do not readily cross the placental barrier see Use in Specific Populations (8.1) .
  • Administer levothyroxine sodium tablets at least 4 hours prior to these drugs or monitor TSH levels.

T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybean infant formula. In addition, many drugs and foods affect T4 absorption (see PRECAUTIONS – Drug Interactions and Drug-Food Interactions ). The majority of the SYNTHROID dose is absorbed from the jejunum and upper ileum. In addition, many drugs and foods affect T4 absorption see Drug Interactions (7). HypothyroidismSYNTHROID® (levothyroxine sodium) tablets, for oral use is indicated as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.

Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma. Initiate SYNTHROID 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). Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of SYNTHROID see Warnings and Precautions (5.1) and Use in Specific Populations (8.4). So, as a reminder, SYNTHROID is indicated for the treatment of hypothyroidism.

  • Changes in thyroid status may occur if barbiturates are added or withdrawn from patients being treated for hypothyroidism.
  • Thyroid hormones, including SYNTHROID, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss.
  • Seizures have been reported rarely with the institution of levothyroxine therapy.
  • 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.
  • There are certain foods that can interfere with the way SYNTHROID works, particularly we think about high-fiber foods that can interact with the absorption of thyroid medications.

Biotin supplementation is known to interfere with thyroid hormone immunoassays that are based on a biotin and streptavidin interaction, which may result in erroneous thyroid hormone test results. Stop biotin and biotin-containing supplements for at least 2 days prior to thyroid testing. Titrate dosage every 6 to 8 weeks, as needed until the patient is euthyroid. In the treatment of benign nodules and nontoxic multinodular goiter, TSH is generally suppressed to a higher target (e.g., 0.1 to either 0.5 or 1.0 mU/L) than that used for the treatment of thyroid cancer. Levothyroxine sodium is contraindicated if the serum TSH is already suppressed due to the risk of precipitating overt thyrotoxicosis (see CONTRAINDICATIONS – WARNINGS and PRECAUTIONS).

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 signs and symptoms of overdosage are those of hyperthyroidism see Warnings and Precautions (5) and Adverse Reactions (6) . Seizures occurred in a 3-year-old child ingesting 3.6 mg of levothyroxine.

Thyroid hormones do not readily cross the placental barrier (see PRECAUTIONS – Pregnancy). 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). Because of the increased prevalence of cardiovascular disease among the elderly, initiate SYNTHROID at less than the full replacement dose see Dosage and Administration (2.3) and Warnings and Precautions (5.2). 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.

Oral anticoagulants

Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia. If cardiac symptoms develop or worsen, reduce the SYNTHROID dose or withhold for one week and restart at a lower dose. The peak therapeutic effect of a given dose of SYNTHROID may not be attained for 4 to 6 synthroid alopecia weeks. Administer SYNTHROID at least 4 hours before or after drugs known to interfere with SYNTHROID absorption see Drug Interactions (7.1). Administer SYNTHROID as a single daily dose, on an empty stomach, one-half to one hour before breakfast.

Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated, due to increased metabolic clearance of glucocorticoids by thyroid hormone. Patients with diabetes mellitus may require upward adjustments of their antidiabetic therapeutic regimens when treated with levothyroxine (see PRECAUTIONS – Drug Interactions). 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.

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