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Levothyroxine Wikipedia

And SYNTHROID is contraindicated in patients who have uncorrected adrenal insufficiency. Animal studies have not been performed to evaluate the carcinogenic potential, mutagenic potential or effects on fertility of levothyroxine. The synthetic T4 in SYNTHROID is identical to that produced naturally by the human thyroid gland. Although there has been a reported association between prolonged thyroid hormone therapy and breast cancer, this has not been confirmed.

Secondary (Pituitary) and Tertiary (Hypothalamic) Hypothyroidism

It’sresponsible for controlling the body’s metabolism, or the rate at which the body converts food into energy, and for making sure the brain, heart, liver, kidneys, and other organs are working properly. A portion of the conjugated hormone reaches the colon unchanged and is eliminated in the feces. Long-term carcinogenicity studies in animals to evaluate the carcinogenic potential of levothyroxine have not been performed.

Patients need to feel comfortable to alert me of any changes in their status in terms of their symptoms. But also specific medical changes that may indicate there may be a need for a dose change or something that could have affected their thyroid hormone levels. Once the patient and I have decided that thyroid hormone replacement is necessary, we go over the specific reasons for choosing and writing Synthroid as that replacement therapy. I review with the patients the important issues about how to take the medication, as consistency is really the key message. I talk about the fact that it’s important to take the medication in the same timing and pattern each day, take it on an empty stomach minutes before they eat.

SYNTHROID is contraindicated in patients with uncorrected adrenal insufficiency see WARNINGS AND PRECAUTIONS. Patients The SYNTHROID dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer. To minimize the risk of hyperactivity, start at one-fourth the recommended full replacement dosage, and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached. 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. This is important as 32% of patients who think they are on SYNTHROID are actually not given this because substitutions are made at the pharmacy.

  • Consumption of certain foods may affect SYNTHROID absorption thereby necessitating adjustments in dosing see DOSAGE AND ADMINISTRATION.
  • Delays in diagnosis and institution of therapy may have deleterious effects on the child’s intellectual and physical growth and development.
  • If so, advise them to stop biotin supplementation at least 2 days before assessing TSH and/or T4 levels see DOSAGE AND ADMINISTRATION and DRUG INTERACTIONS.
  • Because some preparations of the drug may contain iodine or lactose, patients should tell their doctors about such allergies or reactions to these components.

USE IN SPECIFIC POPULATIONS

  • Thyroid hormones are also metabolized via conjugation with glucuronides and sulfates and excreted directly into the bile and gut where they undergo enterohepatic recirculation.
  • Therefore, the dose of SYNTHROID used for TSH suppression should be individualized based on the specific disease and the patient being treated.
  • The goal of replacement therapy is to achieve and maintain a clinical and biochemical euthyroid state.
  • Pregnant and lactating females need to discuss the dose and use of this medication with their caregivers.
  • Because the long-acting nature of the medication, I do indicate that it may take several months to see an improvement in both of these levels.

Overtreatment with levothyroxine sodium may have adverse cardiovascular effects such as an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias. Concomitant administration of levothyroxine and sympathomimetic agents to patients with coronary artery disease may precipitate coronary insufficiency. The goal of replacement therapy is to achieve and maintain a clinical and biochemical euthyroid state. The goal of suppressive therapy is to inhibit growth and/or function of abnormal thyroid tissue. Hence, the following recommendations serve only as dosing guidelines.

In addition, many drugs and foods affect T4 absorption see DRUG INTERACTIONS. In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage. In patients on a stable and appropriate replacement dosage, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient’s clinical status. Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of levothyroxine sodium from the gastrointestinal tract. Therefore, oral thyroid hormone drug products are not recommended to treat this condition.

DRUG INTERACTIONS

  • SYNTHROID is administered as a single daily dose, preferably one-half to one-hour before breakfast.
  • Approximately 80% of the daily dose of T4 is deiodinated to yield equal amounts of T3 and reverse T3 (rT3).
  • Levothyroxine is one of the ten NTI drug classes most commonly prescribed.
  • Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia.
  • Transfer of thyroid hormone from the mother to the fetus, however, may not be adequate to prevent in utero hypothyroidism.

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 and Use In Specific Populations. Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation. Persistent clinical and laboratory evidence of hypothyroidism despite an apparent adequate replacement dose of SYNTHROID may be evidence of inadequate absorption, poor compliance, drug interactions, or a combination of these factors.

Precautions for Synthroid

A listing of drug-thyroidal axis interactions is contained in Table 2. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with SYNTHROID see CONTRAINDICATIONS. Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in pediatric patients receiving levothyroxine therapy.

Concurrent use of sympathomimetics and SYNTHROID may increase the effects of sympathomimetics or thyroid hormone. Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents synthroid bloating are administered to patients with coronary artery disease. Hypersensitivity reactions to inactive ingredients have occurred in patients treated with thyroid hormone products. These include urticaria, pruritus, skin rash, flushing, angioedema, various gastrointestinal symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness, and wheezing.

Adverse Reactions

T3 and T4 diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. Because your body needs a precise number of thyroid hormone, it’s important to take Synthroid the right way every day, just as your doctor prescribes. This is because how you take Synthroid can affect how well it works. It does this by creating thyroid hormones that are then circulated through the bloodstream to different parts of the body.