Levothyroxine Health Information Library

The pituitary gland sends out TSH, which tells the thyroid to produce the thyroid hormones thyroxine (T4) and triiodothyronine (T3). The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available.

Synthroid Patient Tips

Certain foods and medications can interfere with the way your body absorbs or processes Synthroid. Be sure to let your doctor know if there are any changes to your diet or to the medications you take. You can see a list of the foods and medications that can affect the way Synthroid works here. Elisa shares her journey, from living with hypothyroidism and getting a diagnosis to starting—and continuing—treatment on Synthroid. Biochemical assessment incorporated measurement of serum TSH, T3, and T4. TSH lower limit of quantification was 0.2 mIU/L and upper limit of normal was 5.6 mIU/L, as indicated by the shaded area.

Unithroid is used for hashimoto’s disease, hypothyroidism, after thyroid removal, myxedema coma … Levoxyl treats hypothyroidism (low thyroid hormone) and treats or prevents goiter. NP Thyroid is used for hashimoto’s disease, hypothyroidism, after thyroid removal, thyroid cancer … Tirosint is used for hashimoto’s disease, hypothyroidism, after thyroid removal, myxedema coma … Synthroid can be given to infants and children who cannot swallow whole tablets by crushing the tablet and mixing the freshly crushed tablet in a small amount (5 to 10 mL or 1 to 2 teaspoonfuls) of water and immediately giving the misture by spoon or dropper.

TSH & a normally functioning thyroid

When signs and symptoms raise the index of suspicion, the clinician should obtain a serum TSH level (Figure 12,5–7,15–17). If the TSH level is within the normal reference range, other etiologies for the signs and symptoms that prompted testing should be sought (Table 41,2). If the FT4 level is normal, further thyroid or pituitary evaluation is unnecessary.

Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. synthroid label In older patients, levothyroxine therapy is begun with low doses, usually 25 mcg once a day. Patients require a large initial dose of T4 (300 to 500 mcg IV) or T3 (25 to 50 mcg IV). The intravenous maintenance dose of T4 is 75 to 100 mcg once a day and of T3, 10 to 20 mcg twice a day until T4 can be given orally. Corticosteroids are also given because the possibility of central hypothyroidism usually cannot be initially ruled out. The patient should not be rewarmed rapidly, which may precipitate hypotension or arrhythmias.

Do not store the crushed tablet/water mixture and do not administer it mixed with foods that decrease absorption of levothyroxine, such as soybean-based infant formula. You may not be able to take Synthroid if you have certain medical conditions. 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. With hypothyroidism, the thyroid is unable to produce enough thyroid hormone. The hypothalamus, located in the brain, produces thyrotropin-releasing hormone (TRH) that tells the pituitary gland to make thyroid-stimulating hormone (TSH).

The administration of standard replacement amounts (25 to 37.5 mcg twice a day) results in rapidly increasing serum T3 to between 300 and 1000 ng/dL (4.62 to 15.4 nmol/L) within 4 hours due to its almost complete absorption; these levels return to normal by 24 hours. Additionally, patients receiving liothyronine are chemically hyperthyroid for at least several hours a day, potentially increasing cardiac risks. T3 does not cross the placenta and should not be administered to patients who are pregnant. Myxedema coma is a life-threatening complication of hypothyroidism, usually occurring in patients with a long history of hypothyroidism. Its characteristics include coma with extreme hypothermia (temperature 24° to 32.2° C), areflexia, seizures, and respiratory depression with carbon dioxide retention. Severe hypothermia may be missed unless low-reading thermometers are used.

• Interestingly, the patients that received 2 years of levothyroxine replacement therapy had lower bone density.
• As you get older, you might not need as much Synthroid to keep your thyroid hormones in balance.
• The hypothalamus adjusts the release of thyrotropin-releasing hormone based on circulating levels of thyroid hormone.
• Many older patients with hypothyroidism present with nonspecific geriatric syndromes—confusion, anorexia, weight loss, falling, incontinence, and decreased mobility.

Current Medications:

Some patients with hypothyroidism can be challenging to treat and require special consideration. Use this section to review the cases of Steve, Jennifer, and Diana to see how to effectively manage their hypothyroidism with SYNTHROID (levothyroxine sodium). Synthroid is a prescription medicine used to treat hypothyroidism (low thyroid hormone). Levothyroxine is given when your thyroid does not produce enough of this hormone on its own. A TSH test is used to check the level of thyroid-stimulating hormone in the blood. Your TSH level can indicate if your thyroid gland is working properly.

• The information presented by TraceGains is for informational purposes only.
• Synthroid is also used in patients who need surgery and radioiodine therapy to manage a type of thyroid cancer called well-differentiated thyroid cancer.
• Thyroid hormone levels in the body provide signals to the hypothalamus and pituitary, so they know whether to release more or less TRH and TSH.
• In primary hypothyroidism, there is decreased feedback inhibition of the intact pituitary, and serum TSH is always elevated, whereas serum free T4 is low.

Rapid diagnosis based on clinical judgment, history, and physical examination is imperative, because death is likely without rapid treatment. Precipitating factors include illness, infection, trauma, medications or substances that suppress the central nervous system, and exposure to cold. Many patients with primary hypothyroidism have normal circulating levels of triiodothyronine (T3), probably caused by sustained TSH stimulation of the failing thyroid, resulting in preferential synthesis and secretion of biologically active T3.

Clinical hypothyroidism affects one in 300 people in the United States, with a higher prevalence among female and older patients. Symptoms range from minimal to life-threatening (myxedema coma); more common symptoms include cold intolerance, fatigue, weight gain, dry skin, constipation, and voice changes. The signs and symptoms that suggest thyroid dysfunction are nonspecific and nondiagnostic, especially early in disease presentation; therefore, a diagnosis is based on blood levels of thyroid-stimulating hormone and free thyroxine. Symptom relief and normalized thyroid-stimulating hormone levels are achieved with levothyroxine replacement therapy, started at 1.5 to 1.8 mcg per kg per day. Adding triiodothyronine is not recommended, even in patients with persistent symptoms and normal levels of thyroid-stimulating hormone. Patients older than 60 years or with known or suspected ischemic heart disease should start at a lower dosage of levothyroxine (12.5 to 50 mcg per day).