Endocrine regulation of circadian rhythms npj Biological Timing and Sleep

SYNTHROID should not be discontinued during pregnancy and hypothyroidism diagnosed during pregnancy should be promptly treated. The therapeutic effects of digitalis glycosides may be reduced by levothyroxine. Serum digitalis glycoside levels may be decreased when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides (see Table 2). Carefully monitor glycemic control after starting, changing, or discontinuing SYNTHROID see DRUG INTERACTIONS. Titrate the dose of SYNTHROID carefully and monitor response to titration to avoid these effects see DOSAGE AND ADMINISTRATION.

• So, it’s not just treating a number and following the TSH, it’s also making sure that the patient’s symptoms have improved.
• In the elderly and in patients with cardiovascular disease, SYNTHROID should be initiated at lower doses than those recommended in younger individuals or in patients without cardiac disease.
• Inadequate levothyroxine dosage will produce or fail to ameliorate the signs and symptoms of hypothyroidism.

SYNTHROID- levothyroxine sodium tablet

Importantly, THs are key modulators of energy metabolism, regulating glucose and lipid metabolism in various tissues101,102. TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of SYNTHROID see Warnings and Precautions (5.1)and Use in Specific Populations (8.4). In children in whom a diagnosis of permanent hypothyroidism has not been established, it is recommended that levothyroxine administration be discontinued for a 30-day trial period, but only after the child is at least 3 years of age. If the T4 is low and the TSH high, the diagnosis of permanent hypothyroidism is established, and levothyroxine therapy should be reinstituted. If the T4 and TSH levels are normal, euthyroidism may be assumed and, therefore, the hypothyroidism can be considered to have been transient.

Administer SYNTHROID to pediatric patients who cannot swallow intact tablets by crushing the tablet, suspending the freshly crushed tablet in a small amount (5 to 10 mL) of water and immediately administering the suspension by spoon or dropper. Do not administer in foods that decrease absorption of SYNTHROID, such as soybean-based infant formula see Drug Interactions (7.9). The target level for TSH suppression in these conditions has not been established with controlled studies. In addition, the efficacy of TSH suppression for benign nodular disease is controversial. Therefore, the dose of SYNTHROID used for TSH suppression should be individualized based on the specific disease and the patient being treated. Thyroid hormones cross the placental barrier to some extent as evidenced by levels in cord blood of athyreotic fetuses being approximately one-third maternal levels.

Patients with Underlying Cardiovascular Disease

Evaluate the need for dosage adjustments when regularly administering within one hour of certain foods that may affect SYNTHROID absorption. SYNTHROID 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 SYNTHROID may induce hyperthyroidism. Levothroid is used for hashimoto’s disease, hypothyroidism, after thyroid removal, myxedema coma … Eltroxin is used for hashimoto’s disease, hypothyroidism, after thyroid removal, myxedema coma …

These consequences include, among others, effects on growth and development, cardiovascular function, bone metabolism, reproductive function, cognitive function, emotional state, gastrointestinal function, and on glucose and lipid metabolism. Many drugs interact with levothyroxine sodium necessitating adjustments in dosing to maintain therapeutic response (see Drug Interactions ). Dosage titration is based on serum TSH or free-T4 see Important Considerations For Dosing. In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage.

Prevention of hyperthyroidism or incomplete treatment of hypothyroidism

In general, levothyroxine therapy should be instituted at full replacement doses as soon as possible. Delays in diagnosis and institution of therapy may have deleterious effects on the child’s intellectual and physical growth and development. Because of the increased prevalence of cardiovascular disease among the elderly, levothyroxine therapy should not be initiated at the full replacement dose (see WARNINGS, PRECAUTIONS , and DOSAGE AND ADMINISTRATION). Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse synthroid identification effects of congenital hypothyroidism on intellectual development as well as on overall physical growth and maturation.

1 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Sex hormones can act as rhythm drivers through their nuclear receptors acting as transcription factors to initiate gene expression. Notably, estrogen and progesterone bind to estrogen-responsive elements (EREs), activating clock genes such as Per2 and Clock. Sex steroid receptors are present in the SCN, suggesting they may modify circadian phase and rhythm in a sex-specific manner87,88,89. If you become pregnant while taking Synthroid, do not stop taking the medicine without your doctor’s advice.

Occasionally, chronic autoimmune thyroiditis may occur in association with other autoimmune disorders such as adrenal insufficiency, pernicious anemia, and insulin-dependent diabetes mellitus. Patients with concomitant adrenal insufficiency should be treated with replacement glucocorticoids prior to initiation of treatment with levothyroxine sodium. Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated, due to increased metabolic clearance of glucocorticoids by thyroid hormone. Patients with diabetes mellitus may require upward adjustments of their antidiabetic therapeutic regimens when treated with levothyroxine (see PRECAUTIONS – Drug Interactions). Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins (see PRECAUTIONS – Drug Interactions and Drug-Laboratory Test Interactions).

ARE PATIENTS GETTING SYNTHROID

Tell your doctor if you have an untreated or uncontrolled adrenal gland disorder, a thyroid disorder called thyrotoxicosis, or if you have any recent or current symptoms of a heart attack. Consumption of certain foods may affect SYNTHROID absorption thereby necessitating adjustments in dosing see Dosage and Administration (2.1). Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of SYNTHROID from the gastrointestinal tract.

SYNTHROID should be taken at least 4 hours apart from drugs that are known to interfere with its absorption (see PRECAUTIONS – Drug Interactions). Treated children may manifest a period of catch-up growth, which may be adequate in some cases to normalize adult height. In children with severe or prolonged hypothyroidism, catch-up growth may not be adequate to normalize adult height. During the first 2 weeks of SYNTHROID therapy, infants should be closely monitored for cardiac overload, arrhythmias, and aspiration from avid suckling.