Hypothyroidism: A Closer Look

SYNTHROID® (levothyroxine sodium) tablets, for oral use is a prescription, man-made thyroid hormone that is used to treat a condition called hypothyroidism in adults and children, including infants. It is meant to replace a hormone that is usually made by your thyroid gland. Generally, thyroid replacement treatment is to be taken for life. SYNTHROID should not be used to treat noncancerous growths or enlargement of the thyroid in patients with normal iodine levels, or in cases of temporary hypothyroidism caused by inflammation of the thyroid gland (thyroiditis). Thyroid hormones, including SYNTHROID, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss.

6 Decreased Bone Mineral Density Associated with Thyroid Hormone Over-Replacement

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. Patients The SYNTHROID dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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. Reduce the SYNTHROID dosage or discontinue temporarily if signs or symptoms of overdosage occur.

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. 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). Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly. Over-treatment 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 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).

PATIENT SUPPORT WEBSITE

Our Synthroid Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication. Armour Thyroid is used for hashimoto’s disease, hypothyroidism, after thyroid removal, thyroid … This is not a complete list of side effects and others may occur. It may take several weeks before your body starts to respond to Synthroid. Follow all directions on your prescription label and read all medication guides or instruction sheets. You may not be able to take Synthroid if you have certain medical conditions.

• Stop biotin and biotin-containing supplements for at least 2 days prior to thyroid testing.
• 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.
• 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.
• Levoxyl treats hypothyroidism (low thyroid hormone) and treats or prevents goiter.
• Many drugs can inhibit Synthroid’s adsorption by the body; other medications may increase or decrease its effectiveness once it is adsorbed.

Foods containing soy and cottonseed meal can make Synthroid less effective. Walnuts, grapefruit juice, and dietary fiber can also make Synthroid less effective. If you eat any of these on a regular basis, check with your doctor.

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. Carefully monitor glycemic control after starting, changing, or discontinuing SYNTHROID see DRUG INTERACTIONS. Concurrent use of sympathomimetics and SYNTHROID may increase the effects of sympathomimetics or thyroid hormone.

SYNTHROID 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. Do not store the crushed tablet/water mixture and do not administer it mixed with foods that decrease absorption of levothyroxine, such as soybean-based infant formula.

4 Monitoring TSH and/or Thyroxine (T Levels

• Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the SYNTHROID dose is increased.
• Join the Before Breakfast Club for resources to help you stay on track with treatment as well as ways to save on your Synthroid prescription.
• SYNTHROID may reduce the therapeutic effects of digitalis glycosides.

Since thyroid hormone occurs naturally in the body, almost anyone can take levothyroxine. However, you may not be able to take this medicine if you have certain medical conditions. The “optimal dose” was determined for each patient as that dosage of thyroxine being taken when the thyrotropin-releasing hormone (TRH) response was normal (ie, an increase in TSH of between 4.7 and 25 mIU/L). Because the thyroid can’t respond properly, the hypothalamus sends out more TRH and the pituitary keeps releasing more TSH. A high level of TSH plus low thyroid hormone levels indicates hypothyroidism.

WARNINGS AND PRECAUTIONS

Initiate appropriate supportive treatment as dictated by the patient’s medical status. 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 synthroid imitrex concentration. Nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, androgens, and corticosteroids decrease TBG concentration.