INDICATION AND USAGE

TIROSINT is L-thyroxine (T4) indicated for adults and pediatric patients 6 years and older with:

• Hypothyroidism – As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.
• Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) Suppression – As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer.

Limitations of Use:

• TIROSINT is not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients.
• TIROSINT is not indicated for treatment of transient hypothyroidism during the recovery phase of subacute thyroiditis.

IMPORTANT SAFETY INFORMATION

Contraindications

• TIROSINT is contraindicated in patients with uncorrected adrenal insufficiency.

Warnings and Precautions 

• Cardiac adverse reactions in the elderly and in patients with underlying cardiovascular disease: Initiate TIROSINT 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 TIROSINT treatment.
• 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.
• 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.
• Decreased bone mineral density associated with thyroid hormone over-replacement: Over-replacement can increase bone reabsorption and decrease bone mineral density. Give the lowest effective dose.

Adverse Reactions 

Adverse reactions with levothyroxine 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, muscle spasm
• Cardiovascular: palpitations, tachycardia, arrythmias, increased pulse and blood pressure, heart failure, angina, myocardial
  infarction, cardiac arrest
• Respiratory: dyspnea
• Gastrointestinal (GI): diarrhea, vomiting, abdominal cramps, elevations in liver function tests
• Dermatologic: hair loss, flushing, rash
• Endocrine: decreased bone mineral density
• Reproductive: menstrual irregularities, impaired fertility

Adverse Reactions in Children

Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in children receiving levothyroxine therapy. Overtreatment may result in craniosynostosis in infants and premature closure of the epiphyses in children with resultant compromised adult height. Seizures have been reported rarely with the institution of levothyroxine therapy.

Hypersensitivity Reactions

Hypersensitivity reactions to inactive ingredients (in this product or other levothyroxine products) have occurred in patients treated with thyroid hormone products. These include urticaria, pruritis, skin rash, flushing, angioedema, various GI symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness and wheezing. Hypersensitivity to levothyroxine itself is not known to occur.

Drug Interactions

Many drugs and some foods 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 TIROSINT. Administer at least 4 hours before or after drugs that are known to interfere with absorption. See full prescribing information for drugs that affect thyroid hormone pharmacokinetics and metabolism.

Please click here for Full Prescribing Information, including BOXED WARNING, for TIROSINT.