Armour® Thyroid (thyroid tablets, USP) for oral use is a natural preparation derived from porcine thyroid glands and has a strong, characteristic odor. (T₃ liothyronine is approximately four times as potent as T₄ levothyroxine on a microgram for microgram basis.) They provide 38 mcg levothyroxine (T₄) and 9 mcg liothyronine (T₃) per grain of thyroid. The inactive ingredients are calcium stearate, dextrose, microcrystalline cellulose, sodium starch glycolate and opadry white.

Last updated on RxList: 1/4/2008

Armour Thyroid tablets are indicated:

1. As replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis. This category includes cretinism, myxedema, and ordinary hypothyroidism in patients of any age (children, adults, the elderly), or state (including pregnancy); primary hypothyroidism resulting from functional deficiency, primary atrophy, partial or total absence of thyroid gland, or the effects of surgery, radiation, or drugs, with or without the presence of goiter; and secondary (pituitary), or tertiary (hypothalamic) hypothyroidism (See WARNINGS).
2. As pituitary TSH suppressants, in the treatment or prevention of various types of euthyroid goiters, including thyroid nodules, subacute or chronic Iymphocytic thyroiditis (Hashimoto's), multinodular goiter, and in the management of thyroid cancer.
3. As diagnostic agents in suppression tests to differentiate suspected mild hyperthyroidism or thyroid gland autonomy.

The dosage of thyroid hormones is determined by the indication and must in every case be individualized according to patient response and laboratory findings.

Thyroid hormones are given orally. In acute, emergency conditions, injectable levothyroxine sodium (T₄) may be given intravenously when oral administration is not feasible or desirable, as in the treatment of myxedema coma, or during total parenteral nutrition. Intramuscular administration is not advisable because of reported poor absorption.

Hypothyroidism-Therapy is usually instituted using low doses, with increments which depend on the cardiovascular status of the patient. The usual starting dose is 30 mg Armour Thyroid, with increments of 15 mg every 2 to 3 weeks. A lower starting dosage, 15 mg/day, is recommended in patients with long-standing myxedema, particularly if cardiovascular impairment is suspected, in which case extreme caution is recommended. The appearance of angina is an indication for a reduction in dosage. Most patients require 60 to 120 mg/day. Failure to respond to doses of 180 mg suggests lack of compliance or malabsorption. Maintenance dosages 60 to 120 mg/day usually result in normal serum T₄ and T₃ levels. Adequate therapy usually results in normal TSH and T₄ levels after 2 to 3 weeks of therapy.

Readjustment of thyroid hormone dosage should be made within the first four weeks of therapy, after proper clinical and laboratory evaluations, including serum levels of T₄, bound and free, and TSH.

Liothyronine (T₃) may be used in preference to levothyroxine (T₄) during radio-isotope scanning procedures, since induction of hypothyroidism in those cases is more abrupt and can be of shorter duration. It may also be preferred when impairment of peripheral conversion of levothyroxine (T₄) and liothyronine (T₃) is suspected.

Myxedema Coma-Myxedema coma is usually precipitated in the hypothyroid patient of long-standing by intercurrent illness or drugs such as sedatives and anesthetics and should be considered a medical emergency. Therapy should be directed at the correction of electrolyte disturbances and possible infection besides the administration of thyroid hormones. Corticosteroids should be administered routinely. Levothyroxine (T₄) and liothyronine (T₃) may be administered via a nasogastric tube but the preferred route of administration of both hormones is intravenous. Levothyroxine sodium (T₄) is given at a starting dose of 400 mcg (100 mcg/mL) given rapidly, and is usually well tolerated, even in the elderly. This initial dose is followed by daily supplements of 100 to 200 mcg given I V. Normal T₄ levels are achieved in 24 hours followed in 3 days by threefold elevation of T₃. Oral therapy with thyroid hormone would be resumed as soon as the clinical situation has been stabilized and the patient is able to take oral medication.

Thyroid Cancer-Exogenous thyroid hormone may produce regression of metastases from follicular and papillary carcinoma of the thyroid and is used as ancillary therapy of these conditions with radioactive iodine. TSH should be suppressed to low or undetectable levels. Therefore, larger amounts of thyroid hormone than those used for replacement therapy are required. Medullary carcinoma of the thyroid is usually unresponsive to this therapy.

Thyroid Suppression Therapy-Administration of thyroid hormone in doses higher than those produced physiologically by the gland results in suppression of the production of endogenous hormone. This is the basis for the thyroid suppression test and is used as an aid in the diagnosis of patients with signs of mild hyperthyroidism in whom base line laboratory tests appear normal, or to demonstrate thyroid gland autonomy in patients with Grave's ophthalmopathy. 131I uptake is determined before and after the administration of the exogenous hormone. A 50 percent or greater suppression of uptake indicates a normal thyroid-pituitary axis and thus rules out thyroid gland autonomy.

For adults, the usual suppressive dose of levothyroxine (T₄) is 1.56 mcg/kg of body weight per day given for 7 to 10 days. These doses usually yield normal serum T₄ and T₃ levels and lack of response to TSH.

Thyroid hormones should be administered cautiously to patients in whom there is strong suspicion of thyroid gland autonomy, in view of the fact that the exogenous hormone effects will be additive to the endogenous source.

Pediatric Dosage-Pediatric dosage should follow the recommendations summarized in Table 1. In infants with congenital hypothyroidism, therapy with full doses should be instituted as soon as the diagnosis has been made.

Recommended Pediatric Dosage for Congenital Hypothyroidism

	Armour Thyroid Tablets
Age	Dose per day	Daily dose per kg of body weight
0-6 mos	15-30 mg	4.8-6 mg
6-12 mos	30-45 mg	3.6-4.8 mg
1-5 yrs	45-60 mg	3-3.6 mg
6-12 yrs	60-90 mg	2.4-3 mg
Over 12 yrs	Over 90 mg	1.2-1.8 mg

Armour Thyroid tablets (thyroid tablets, USP) are supplied as follows: 15 mg (1/4 gr) are available in bottles of 100 (NDC 0456- 0457-01). 30 mg (1/2 gr) are available in bottles of 100 (NDC 0456-0458-01), 1000 (NDC 0456-0458-00), containers of 50,000 (NDC 0456-0458-69) and unit dose cartons of 100 (NDC 0456-0458-63). 60 mg (1 gr) are available in bottles of 100 (NDC 0456- 0459-01), 1000 (NDC 0456-0459-00), 5000 (NDC 0456-0459-51), containers of 50,000 (0456-0459-69) and unit dose cartons of 100 (NDC 0456-0459-63). 90 mg (1 1/2 gr) are available in bottles of 100 (NDC 0456-0460-01). 120 mg (2 gr) are available in bottles of 100 (NDC 0456-0461-01), 1000 (NDC 0456-0461-00), containers of 50,000 (NDC 0456-0461-69) and unit dose car- tons of 100 (NDC 0456-0461-63). 180 mg (3 gr) are available in bottles of 100 (NDC 0456-0462-01) and 1000 (NDC 0456-0462- 00). 240 mg (4 gr) are available in bottles of 100 (NDC 0456-0463-01). 300 mg (5 gr) are available in bottles of 100 (NDC 0456- 0464-01). The bottles of 100 are special dispensing bottles with child-resistant closures.

Armour Thyroid tablets are evenly colored, light tan, round tablets, with convex surfaces. One side is debossed with a mortar and pestle beneath the letter "A" on the top and strength code letters on the bottom as defined below

Strength	Code
1/4 grain	TC
1/2 grain	TD
1 grain	TE
1 1/2 grain	TJ
2 grain	TF
3 grain	TG (bisected)
4 grain	TH
5 grain	TI (bisected)

Note: (T₃ liothyronine is approximately four times as potent as T₄ levothyroxine on a microgram for microgram basis.)

Tablets should be stored at controlled room temperature, 59°-86° F (15°-30° C), in capped bottles or unbroken plastic strip packing.

Forest Pharmaceuticals, Inc. A Subsidiary of Forest Laboratories, Inc. St. Louis, MO 63045. Rev. 11/02.

Last updated on RxList: 1/23/2008

Adverse reactions other than those indicative of hyperthyroidism because of therapeutic overdosage, either initially or during the maintenance period, are rare (See OVERDOSE).

Oral Anticoagulants-Thyroid hormones appear to increase catabolism of vitamin K-dependent clotting factors. If oral anticoagulants are also being given, compensatory increases in clotting factor synthesis are impaired. Patients stabilized on oral anticoagulants who are found to require thyroid replacement therapy should be watched very closely when thyroid is started. If a patient is truly hypothyroid, it is likely that a reduction in anticoagulant dosage will be required. No special precautions appear to be necessary when oral anticoagulant therapy is begun in a patient already stabilized on maintenance thyroid replacement therapy.

Insulin or Oral Hypoglycemics-Initiating thyroid replacement therapy may cause increases in insulin or oral hypoglycemic requirements. The effects seen are poorly understood and depend upon a variety of factors such as dose and type of thyroid preparations and endocrine status of the patient. Patients receiving insulin or oral hypoglycemics should be closely watched during initiation of thyroid replacement therapy.

Cholestyramine or Colestipol-Cholestyramine or colestipol binds both levothyroxine (T₄) and liothyronine (T₃) in the intestine, thus impairing absorption of these thyroid hormones. In vitro studies indicate that the binding is not easily removed. Therefore four to five hours should elapse between administration of cholestyramine or colestipol and thyroid hormones.

Estrogen, Oral Contraceptives-Estrogens tend to increase serum thyroxine-binding globulin (TBg). In a patient with a nonfunctioning thyroid gland who is receiving thyroid replacement therapy, free levothyroxine (T₄) may be decreased when estrogens are started thus increasing thyroid requirements. However, if the patient's thyroid gland has sufficient function, the decreased free levothyroxine (T₄) will result in a compensatory increase in levothyroxine (T₄) output by the thyroid. Therefore, patients without a functioning thyroid gland who are on thyroid replacement therapy may need to increase their thyroid dose if estrogens or estrogen-containing oral contraceptives are given.

Drug/Laboratory Test Interactions-The following drugs or moieties are known to interfere with laboratory tests performed in patients on thyroid hormone therapy: androgens, corticosteroids, estrogens, oral contraceptives containing estrogens, iodine-containing preparations, and the numerous preparations containing salicylates.

1. Changes in TBg concentration should be taken into consideration in the interpretation of levothyroxine (T₄) and liothyronine (T₃) values. In such cases, the unbound (free) hormone should be measured. Pregnancy, estrogens, and estrogen-containing oral contraceptives increase TBg concentrations. TBg may also be increased during infectious hepatitis. Decreases in TBg concentrations are observed in nephrosis, acromegaly, and after androgen or corticosteroid therapy. Familial hyperor hypothyroxine-binding-globulinemias have been described. The incidence of TBg deficiency approximates 1 in 9,000. The binding of levothyroxine by TBPA is inhibited by salicylates.
2. Medicinal or dietary iodine interferes with all in vivo tests of radio-iodine uptake, producing low uptakes which may not be relative of a true decrease in hormone synthesis.
3. The persistence of clinical and laboratory evidence of hypothyroidism in spite of adequate dosage replacement indicates either poor patient compliance, poor absorption, excessive fecal loss, or inactivity of the preparation. Intracellular resistance to thyroid hormone is quite rare.

Last updated on RxList: 1/23/2008

The use of thyroid hormones in the therapy of obesity, alone or combined with other drugs, is unjustified and has been shown to be ineffective. Neither is their use justified for the treatment of male or female infertility unless this condition is accompanied by hypothyroidism.

General-Thyroid hormones should be used with great caution in a number of circumstances where the integrity of the cardiovascular system, particularly the coronary arteries, is suspected. These include patients with angina pectoris or the elderly, in whom there is a greater likelihood of occult cardiac disease. In these patients therapy should be initiated with low doses, i.e., 15-30 mg Armour Thyroid. When, in such patients, a euthyroid state can only be reached at the expense of an aggravation of the cardiovascular disease, thyroid hormone dosage should be reduced.

Thyroid hormone therapy in patients with concomitant diabetes mellitus or diabetes insipidus or adrenal cortical insufficiency aggravates the intensity of their symptoms. Appropriate adjustments of the various therapeutic measures directed at these concomitant endocrine diseases are required. The therapy of myxedema coma requires simultaneous administration of glucocorticoids (See DOSAGE AND ADMINISTRATION).

Hypothyroidism decreases and hyperthyroidism increases the sensitivity to oral anticoagulants. Prothrombin time should be closely monitored in thyroid-treated patients on oral anticoagulants and dosage of the latter agents adjusted on the basis of frequent prothrombin time determinations. In infants, excessive doses of thyroid hormone preparations may produce craniosynostosis.

Laboratory Tests-Treatment of patients with thyroid hormones requires the periodic assessment of thyroid status by means of appropriate laboratory tests besides the full clinical evaluation. The TSH suppression test can be used to test the effectiveness of any thyroid preparation bearing in mind the relative insensitivity of the infant pituitary to the negative feedback effect of thyroid hormones. Serum T₄ levels can be used to test the effectiveness of all thyroid medications except T₃. When the total serum T₄ is low but TSH is normal, a test specific to assess unbound (free) T₄ levels is warranted. Specific measurements of T₄ and T₃ by competitive protein binding or radioimmunoassay are not influenced by blood levels of organic or inorganic iodine.

Carcinogenesis, Mutagenesis, and Impairment of Fertility-A reportedly apparent association between prolonged thyroid therapy and breast cancer has not been confirmed and patients on thyroid for established indications should not discontinue therapy. No confirmatory long-term studies in animals have been performed to evaluate carcinogenic potential, mutagenicity, or impairment of fertility in either males or females.

Pregnancy-Category A-Thyroid hormones do not readily cross the placental barrier. The clinical experience to date does not indicate any adverse effect on fetuses when thyroid hormones are administered to pregnant women. On the basis of current knowledge, thyroid replacement therapy to hypothyroid women should not be discontinued during pregnancy.

Nursing Mothers-Minimal amounts of thyroid hormones are excreted in human milk. Thyroid is not associated with serious adverse reactions and does not have a known tumorigenic potential. However, caution should be exercised when thyroid is administered to a nursing woman.

Pediatric Use-Pregnant mothers provide little or no thyroid hormone to the fetus. The incidence of congenital hypothyroidism is relatively high (1:4,000) and the hypothyroid fetus would not derive any benefit from the small amounts of hormone crossing the placental barrier. Routine determinations of serum T₄ and/or TSH is strongly advised in neonates in view of the deleterious effects of thyroid deficiency on growth and development.

Tr eatment should be initiated immediately upon diagnosis, and maintained for life, unless transient hypothyroidism is suspected; in which case, therapy may be interrupted for 2 to 8 weeks after the age of 3 years to reassess the condition. Cessation of therapy is justified in patients who have maintained a normal TSH during those 2 to 8 weeks.

Last updated on RxList: 1/23/2008

Signs and Symptoms-Excessive doses of thyroid result in a hypermetabolic state resembling in every respect the condition of endogenous origin. The condition may be self-induced.

Treatment of Overdosage-Dosage should be reduced or therapy temporarily discontinued if signs and symptoms of overdosage appear.

Treatment may be reinstituted at a lower dosage. In normal individuals, normal hypothalamic-pituitary-thyroid axis function is restored in 6 to 8 weeks after thyroid suppression.

Tr eatment of acute massive thyroid hormone overdosage is aimed at reducing gastrointestinal absorption of the drugs and counteracting central and peripheral effects, mainly those of increased sympathetic activity. Vomiting may be induced initially if further gastrointestinal absorption can reasonably be prevented and barring contraindications such as coma, convulsions, or loss of the gagging reflex. Treatment is symptomatic and supportive. Oxygen may be administered and ventilation maintained. Cardiac glycosides may be indicated if congestive heart failure develops. Measures to control fever, hypoglycemia, or fluid loss should be instituted if needed. Antiadrenergic agents, particularly propranolol, have been used advantageously in the treatment of increased sympathetic activity. Propranolol may be administered intravenously at a dosage of 1 to 3 mg, over a 10-minute period or orally, 80 to 160 mg/day, initially, especially when no contraindications exist for its use.

Other adjunctive measures may include administration of cholestyramine to interfere with thyroxine absorption, and glucocorticoids to inhibit conversion of T₄ to T₃.

Thyroid hormone preparations are generally contraindicated in patients with diagnosed but as yet uncorrected adrenal cortical insufficiency, untreated thyrotoxicosis, and apparent hypersensitivity to any of their active or extraneous constituents. There is no well-documented evidence from the literature, however, of true allergic or idiosyncratic reactions to thyroid hormone.

Last updated on RxList: 1/4/2008

The steps in the synthesis of the thyroid hormones are controlled by thyrotropin (Thyroid Stimulating Hormone, TSH) secreted by the anterior pituitary. This hormone's secretion is in turn controlled by a feedback mechanism effected by the thyroid hormones themselves and by thyrotropin releasing hormone (TRH), a tripeptide of hypothalamic origin. Endogenous thyroid hormone secretion is suppressed when exogenous thyroid hormones are administered to euthyroid individuals in excess of the normal gland's secretion.

The mechanisms by which thyroid hormones exert their physiologic action are not well understood. These hormones enhance oxygen consumption by most tissues of the body, increase the basal metabolic rate, and the metabolism of carbohydrates, lipids, and proteins. Thus, they exert a profound influence on every organ system in the body and are of particular importance in the development of the central nervous system.

The normal thyroid gland contains approximately 200 mcg of levothyroxine (T₄) per gram of gland, and 15 mcg of liothyronine (T₃) per gram. The ratio of these two hormones in the circulation does not represent the ratio in the thyroid gland, since about 80 percent of peripheral liothyronine (T₃) comes from monodeiodination of levothyroxine (T₄). Peripheral monodeiodination of levothyroxine (T₄) at the 5 position (inner ring) also results in the formation of reverse liothyronine (T₃), which is calorigenically inactive.

Liothyronine (T₃) levels are low in the fetus and newborn, in old age, in chronic caloric deprivation, hepatic cirrhosis, renal failure, surgical stress, and chronic illnesses representing what has been called the "T₃ thyronine syndrome."

Pharmacokinetics - Animal studies have shown that levothyroxine (T₄) is only partially absorbed from the gastrointestinal tract. The degree of absorption is dependent on the vehicle used for its administration and by the character of the intestinal contents, the intestinal flora, including plasma protein, and soluble dietary factors, all of which bind thyroid and thereby make it unavailable for diffusion. Only 41 percent is absorbed when given in a gelatin capsule as opposed to a 74 percent absorption when given with an albumin carrier.

Depending on other factors, absorption has varied from 48 to 79 percent of the administered dose. Fasting increases absorption. Malabsorption syndromes, as well as dietary factors, (children's soybean formula, concomitant use of anionic exchange resins such as cholestyramine) cause excessive fecal loss. Liothyronine (T₃) is almost totally absorbed, 95 percent in 4 hours. The hormones contained in the natural preparations are absorbed in a manner similar to the synthetic hormones.

More than 99 percent of circulating hormones are bound to serum proteins, including thyroid-binding globulin (TBg), thyroid-binding prealbumin (TBPA), and albumin (TBa), whose capacities and affinities vary for the hormones. The higher affinity of levothyroxine (T₄) for both TBg and TBPA as compared to liothyronine (T₃) partially explains the higher serum levels and longer half-life of the former hormone. Both protein bound hormones exist in reverse equilibrium with minute amounts of free hormone, the latter accounting for the metabolic activity.

Deiodination of levothyroxine (T₄) occurs at a number of sites, including liver, kidney, and other tissues. The conjugated hormone, in the form of glucuronide or sulfate, is found in the bile and gut where it may complete an enterohepatic circulation. Eighty-five percent of levothyroxine (T₄) metabolized daily is deiodinated.

Last updated on RxList: 1/4/2008

Patients on thyroid hormone preparations and parents of children on thyroid therapy should be informed that:

1. Replacement therapy is to be taken essentially for life, with the exception of cases of transient hypothyroidism, usually associated with thyroiditis, and in those patients receiving a therapeutic trial of the drug.
2. They should immediately report during the course of therapy any signs or symptoms of thyroid hormone toxicity, e.g., chest pain, increased pulse rate, palpitations, excessive sweating, heat intolerance, nervousness, or any other unusual event.
3. In case of concomitant diabetes mellitus, the daily dosage of antidiabetic medication may need readjustment as thyroid hormone replacement is achieved. If thyroid medication is stopped, a downward readjustment of the dosage of insulin or oral hypoglycemic agent may be necessary to avoid hypoglycemia. At all times, close monitoring of urinary glucose levels is mandatory in such patients.
4. In case of concomitant oral anticoagulant therapy, the prothrombin time should be measured frequently to determine if the dosage of oral anticoagulants is to be readjusted.
5. Partial loss of hair may be experienced by children in the first few months of thyroid therapy, but this is usually a transient phenomenon and later recovery is usually the rule.

Last updated on RxList: 1/4/2008

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

THYROID - ORAL

(THYE-roid)

COMMON BRAND NAME(S): Armour Thyroid

WARNING: Thyroid hormone should not be used either alone or in combination with diet pills to treat obesity/cause weight loss in patients with normal thyroid production. If used in combination with diet pills (appetite-suppressant drugs), serious, even life-threatening effects could occur.

USES: Thyroid hormone is a natural product made from animal thyroid glands (usually pig). It contains 2 natural chemicals (liothyronine and levothyroxine) that are normally produced by the thyroid gland. It is used to treat underactive thyroid (hypothyroidism). Low thyroid levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery. It is important to have adequate levels of thyroid hormones in your bloodstream to maintain normal mental and physical activity.

This medication is also used to lower thyroid function in certain diseases such as enlarged thyroid gland (goiter) and Hashimoto's thyroiditis. It is also used to manage thyroid cancer and to test thyroid activity. Thyroid hormone should not be used for male or female infertility in patients with normal thyroid production. The risks of use are high and thyroid hormone provides no benefit.

HOW TO USE: Take this medication by mouth, usually once daily before breakfast or as directed by your doctor.

Dosage is based on your medical condition, thyroid hormone levels, and response to therapy. There are different brands of thyroid hormone available. They are not interchangeable because the amounts of the 2 thyroid hormones may be different in each product. Do not change brands without first consulting your doctor or pharmacist.

Take this medication 4 hours before or after taking any products containing aluminum or iron, such as antacids, sucralfate, and vitamins/minerals. Take this medication 4-5 hours after taking any bile acid-binding resins such as cholestyramine and colestipol. These products react with thyroid, preventing its full absorption.

Certain foods and supplements (e.g., children's soy formula) may affect how much thyroid hormone is absorbed. Talk with your doctor or pharmacist for more information.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day. Do not stop taking this medication without talking with your doctor. Thyroid replacement therapy is usually taken for life.

Symptoms of low thyroid levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heart rate and sensitivity to cold. Inform your doctor if your condition persists or worsens after 2 to 3 days of treatment.

SIDE EFFECTS: Nausea and partial hair loss (temporary) may occur in children in the first few months of starting thyroid hormone. If either of these changes persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

It is also possible to have too much thyroid hormone. Tell your doctor immediately if any of these signs of too much thyroid hormone occur: diarrhea, headache, heat intolerance, irritability, menstrual changes, nervousness, trouble sleeping, heavy sweating, unusual weight loss.

Tell your doctor immediately if any of these rare but very serious side effects occur: fast/irregular/pounding heartbeat, trouble breathing with exercise, swelling of the arms/legs, extreme weakness.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest/jaw/left arm pain.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking thyroid hormone, tell your doctor or pharmacist if you are allergic to it; or to pork; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: decreased adrenal gland function, kidney disease (e.g., nephrosis), low pituitary hormone (e.g., hypopituitarism), low testosterone (e.g., hypogonadism), overactive thyroid (hyperthyroidism).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: poor food absorption (malabsorption syndrome), heart disease (e.g., angina, high blood pressure, heart failure, irregular heartbeat, heart attack), sugar diabetes (diabetes mellitus), water diabetes (diabetes insipidus), long-term severe underactive thyroid (e.g., myxedema).

Before having surgery, tell your doctor or dentist that you are using this medication.

If you have diabetes, this drug may make it harder to control your blood sugar levels. Check your blood sugar regularly as directed by your doctor. Tell your doctor immediately if you have symptoms such as increased thirst/urination, shakiness, unusual sweating, and hunger. Your anti-diabetic medication or diet may need to be adjusted.

Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially the effects on the heart.

Current information shows that this drug may be used during pregnancy. Tell your doctor if you are pregnant or intend to become pregnant.

Thyroid hormone passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: See also How to Use Section.

Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: certain antidepressants (e.g., TCAs such as amitriptyline, imipramine, nortriptyline), diabetes drugs (e.g., glipizide, insulin, metformin, rosiglitazone), digoxin, estrogens (e.g., birth control pills/patch/ring, hormone replacement therapy), ketamine, intravenous blood pressure drugs (e.g., epinephrine, norepinephrine), "blood thinners" (e.g., warfarin).

Check the labels on all your medicines (e.g., cough-and-cold products, diet aids) because they may contain ingredients that could increase your heart rate or blood pressure. Ask your pharmacist about the safe use of those products.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include: fever, fast/irregular heartbeat, chest pain, confusion.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., thyroid function tests) should be performed regularly to monitor your progress or check for side effects. Some drugs (e.g., androgens, corticosteroids, estrogens, estrogen-containing birth control pills, iodine-containing products, salicylates) can interfere with thyroid function tests, possibly causing false test results. Consult your laboratory personnel or doctor for more details.

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.