Up to 15% of women over 65 years of age have elevated TSH levels1

It’s time to be precise With Synthroid® Available in 12 dose strengths to meet the individual needs of your patients.

25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg,125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg and 300 mcg

SYNTHROID® (levothyroxine sodium tablets, USP)2

Indications and Clinical use

  • Hypothyroidism: SYNTHROID® (levothyroxine sodium) is indicated as a replacement or supplemental therapy in patients of any age with primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) hypothyroidism of any etiology, in any state (including pregnancy) except transient hypothyroidism during the recovery phase of subacute thyroiditis.
  • Pituitary Thyrotropin (Thyroid-stimulating hormone, TSH) Suppression: SYNTHROID® is indicated as an adjunct to surgery and radioactive iodine therapy in the management of thyrotropin-dependent well-differentiated papillary or follicular carcinoma of the thyroid.

Most Serious Warnings and Precautions:

  • Treatment of obesity or for weight loss: Thyroid hormones, including SYNTHROID®, 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. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
  • Bioavailability: The bioavailability of levothyroxine may differ to some extent among marketed brands. Once the patient is stabilized on a particular brand of levothyroxine sodium, caution should be exercised when a change in drug product brand is implemented. If a switch to another levothyroxine-containing product is required, there is a need to undertake close clinical and biological monitoring during the transition period due to a potential risk of imbalance. In some patients, a dose adjustment could be necessary.
  • Differences in formulations: It has been shown that differences in formulations of levothyroxine, despite an identical content of active ingredient, may be associated with differences in fractional gastrointestinal absorption. These differences may not be observed through measurement of total T3 and T4 serum levels. It is therefore recommended that patients who are switched from one levothyroxine formulation to another be re-titrated to the desired thyroid function. Accuracy in re-titration can best be achieved by using sensitive thyrotropin assays.

Other relevant warnings and precautions:

  • Levothyroxine has a narrow therapeutic index; careful dosage titration is necessary to avoid the consequences of over- or under-treatment
  • Seizures
  • Use with caution in patients with cardiovascular disorders, including angina, coronary artery disease and hypertension, and in the elderly
  • Monitor for changes in thyroid function in patients treated concomitantly with orlistat
  • Increased bone resorption in women
  • Use in patients with nontoxic diffuse goiter or nodular thyroid disease
  • Hypothalamic/pituitary hormone deficiencies
  • Myxedema Coma
  • Malabsorption syndromes: thyroxine absorption is decreased in patients with malabsorption syndromes, it is advised to treat the malabsorption condition to ensure effective thyroxine treatment with regular thyroxine dose.
  • Response to anticoagulant therapy enhanced by T4
  • Autoimmune Polyglandular Syndrome: occasionally, chronic autoimmune thyroiditis may occur in association with other autoimmune disorders such as adrenal insufficiency, pernicious anemia, and insulin-dependent diabetes mellitus. Use of SYNTHROID® in patients with concomitant diabetes mellitus, diabetes insipidus or adrenal cortical insufficiency may aggravate the intensity of their symptoms.
  • Use in patients at risk of psychotic disorders
  • Treatment of male or female infertility associated with hypothyroidism
  • Pregnant or nursing women, pediatrics, and geriatrics
  • Monitoring and laboratory tests
  • Drug interactions may necessitate adjustments in dosing or monitoring to maintain therapeutic response
  • Driving and operating machinery: exercise caution when driving or operating a vehicle or potentially dangerous machinery.

For more information

Consult the Product Monograph at https://health-products.canada.ca/dpd-bdpp/index-eng.jsp for more information about conditions of clinical use, contraindications, warnings, precautions, adverse reactions, interactions and dosing. The Product Monograph is also available by calling 1-844-596-9526.

References:

  1. 1.Canaris GJ, et al. The Colorado Thyroid Disease Prevalence Study. Arch Intern Med 2000; 160(4):526-34.
  2. 2.SYNTHROID (levothyroxine sodium tablets, USP) Product Monograph. BGP Pharma ULC. October 08, 2024.