Liothyronine: uses, appearance and warnings

Liothyronine sodium is an L-triiodothyronine (T3) indicated for: • Hypothyroidism: As replacement in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism ( 1.1 ) • Pituitary Thyroid-Stimulating Hormone (TSH) Suppression: As an adjunct to surgery and radioiodine therapy in the management of well-differentiated thyroid cancer ( 1.2 ) • Thyroid Suppression Test: As a diagnostic agent in suppression tests to differentiate suspected mild hyperthyroidism or thyroid gland autonomy ( 1.3 ) Limitations of Use : - Not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients. ( 1 ) - Not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis. ( 1 ) 1.1 Hypothyroidism Liothyronine sodium is indicated as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. 1.2 Pituitary Thyroid-Stimulating Hormone (TSH) Suppression Liothyronine sodium is indicated as an adjunct to surgery and radioiodine therapy in the management of well-differentiated thyroid cancer . 1.3 Thyroid Suppression Test Liothyronine sodium is indicated as a diagnostic agent in suppression tests to differentiate suspected mild hyperthyroidism or thyroid gland autonomy. Limitations of Use • Liothyronine sodium is 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 liothyronine sodium may induce hyperthyroidism [see Warnings and Precautions (5.4) ] . • Liothyronine sodium is not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis.

Tablets (round, white to off-white) available as follows: • 5 mcg: debossed with KPI on one side and 115 on the other side • 25 mcg: scored on one side and debossed with KPI and 116 on the other side • 50 mcg: scored on one side and debossed with KPI and 117 on the other side Tablets: 5 mcg, 25 mcg, 50 mcg ( 3 )

Liothyronine sodium tablets (round, white to off-white) are supplied as follows: Strength Tablet Markings NDC – bottles of 100 5 mcg Debossed with KPI on one side and 115 on the other side 59762-1206-1 25 mcg Scored on one side and debossed with KPI and 116 on the other side 59762-1207-1 50 mcg Scored on one side and debossed with KPI and 117 on the other side 59762-1208-1 Store between 15°C and 30°C (59°F and 86°F).

Liothyronine sodium is contraindicated in patients with uncorrected adrenal insufficiency [see Warnings and Precautions (5.3) ] . Uncorrected adrenal cortical insufficiency ( 4 )

• Cardiac adverse reactions in the elderly and in patients with underlying cardiovascular disease: Initiate liothyronine sodium at less than the full replacement dose because of the increased risk of cardiac adverse reactions, including atrial fibrillation ( 2.3 , 5.1 , 8.5 ) • Myxedema coma: Do not use oral thyroid hormone drug products to treat myxedema coma ( 5.2 ) • Acute adrenal crisis in patients with concomitant adrenal insufficiency: Treat with replacement glucocorticoids prior to initiation of liothyronine sodium treatment ( 5.3 ) • Prevention of hyperthyroidism or incomplete treatment of hypothyroidism: Proper dose titration and careful monitoring is critical to prevent the persistence of hypothyroidism or the development of hyperthyroidism ( 5.4 ) • Worsening of diabetic control: Therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing thyroid hormone therapy ( 5.5 ) • Decreased bone mineral density associated with thyroid hormone over-replacement: Over-replacement can increase bone resorption and decrease bone mineral density. Give the lowest effective dose ( 5.6 ) 5.1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease Overtreatment with thyroid hormone 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 liothyronine sodium 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 liothyronine sodium therapy. Monitor patients receiving concomitant liothyronine sodium and sympathomimetic agents for signs and symptoms of coronary insufficiency. If cardiovascular symptoms develop or worsen, reduce or withhold the liothyronine sodium dose 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 thyroid hormone 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 may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with liothyronine sodium [see Contraindications (4) ]. 5.4 Prevention of Hyperthyroidism or Incomplete Treatment of Hypothyroidism Liothyronine sodium has a narrow therapeutic index. Over- or undertreatment with liothyronine sodium 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 liothyronine sodium 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 liothyronine sodium and adjust the dose as necessary [see Drug Interactions (7) and Clinical Pharmacology (12.3) ]. 5.5 Worsening of Diabetic Control Addition of thyroid hormone therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing liothyronine sodium [see Drug Interactions (7.2) ]. 5.6 Decreased Bone Mineral Density Associated with Thyroid Hormone Over-Replacement Increased bone resorption and decreased bone mineral density may occur as a result of thyroid hormone over-replacement, particularly in post-menopausal women. The increased bone resorption may be associated with increased serum levels and urinary excretion of calcium and phosphorous, elevations in bone alkaline phosphatase, and suppressed serum parathyroid hormone levels. Administer the minimum dose of liothyronine sodium that achieves the desired clinical and biochemical response to mitigate against this risk.

Adverse reactions associated with liothyronine sodium therapy are primarily those of hyperthyroidism due to therapeutic overdosage [see Warnings and Precautions (5.4) and Overdosage (10) ] . They include the following: General : fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating Central nervous system : headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia Musculoskeletal : tremors, muscle weakness and cramps Cardiovascular : palpitations, tachycardia, arrhythmias, increased pulse and blood pressure, heart failure, angina, myocardial infarction, cardiac arrest Respiratory : dyspnea Gastrointestinal : diarrhea, vomiting, abdominal cramps, elevations in liver function tests Dermatologic : hair loss, flushing Endocrine : decreased bone mineral density Reproductive : menstrual irregularities, impaired fertility Most commo …

See full prescribing information for drugs that affect thyroid hormone pharmacokinetics and metabolism (e.g., absorption, synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to liothyronine sodium ( 7 ) 7.1 Drugs Known to Affect Thyroid Hormone Pharmacokinetics Many drugs can exert effects on thyroid hormone pharmacokinetics (e.g. absorption, synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to liothyronine sodium (see Tables 1 – 4). Table 1: Drugs That May Decrease T3 Absorption (Hypothyroidism) Potential impact: Concurrent use may reduce the efficacy of liothyronine sodium by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. …