Liothyronine

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

Thyroid hormones exert their physiologic actions through control of DNA transcription and protein synthesis. Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. 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.

• Administer liothyronine sodium orally once daily and individual dosage according to patient response and laboratory findings. • See full prescribing information for recommended dosage for hypothyroidism. TSH suppression in well-differentiated thyroid cancer and for thyroid suppression test. • When switching a patient to liothyronine sodium, discontinue levothyroxine therapy and initiate liothyronine sodium at a low dosage. Gradually increase the dose according to the patient's response. • Adequacy of therapy determined with periodic monitoring of TSH and T3 levels as well as clinical status

Liothyronine sodium is contraindicated in patients with uncorrected adrenal insufficiency. Uncorrected adrenal cortical insufficiency

Boxed warning (not for treatment of obesity or for weight loss •): Thyroid hormones, including LIOTHYRONINE SODIUM, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. • In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. • 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. • Myxedema coma: Do not use oral thyroid hormone drug products to treat myxedema coma. • Acute adrenal crisis in patients with concomitant adrenal insufficiency: Treat with replacement glucocorticoids prior to initiation of liothyronine sodium treatment.

Adverse reactions associated with liothyronine sodium therapy are primarily those of hyperthyroidism due to therapeutic overdosage. 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 common adverse reactions for liothyronine sodium are primarily those of hyperthyroidism due to therapeutic overdosage: arrhythmias, myocardial infarction, dyspnea, headache, nervousness, irritability, insomnia, tremors, muscle weakness, increased appetite, weight loss, diarrhea, heat intolerance, menstrual irregularities, and skin rash.

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

Store between 15°C and 30°C (59°F and 86°F).