L-Thyroxine 100 mcg tablets 100, Levothyroxine sodium
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Active substance: levothyroxine sodium 100 mg.
Excipients: calcium hydrogen phosphate aqueous; MCC; carboxymethyl starch sodium salt (type A); dextrin; long-chain partial glycerides.
Synthetic thyroid hormone preparation, levorotatory isomer of thyroxine. After partial conversion to triiodothyronine (in the liver and kidneys) and transition to the cells of the body, it affects the development and growth of tissues, on metabolism.
In small doses, it has an anabolic effect on protein and fat metabolism. In medium doses, it stimulates growth and development, increases the need of tissues for oxygen, stimulates the metabolism of proteins, fats and carbohydrates, increases the functional activity of the cardiovascular system and the central nervous system. In high doses, it inhibits the production of TTRG of the hypothalamus and TSH of the pituitary gland.
The therapeutic effect is observed after 7-12 days, during the same time the effect remains after discontinuation of the drug. The clinical effect of hypothyroidism is manifested after 3-5 days. Diffuse goiter decreases or disappears within 3-6 months.
Indications for use
Hypothyroidism (hypothyroidism) of any genesis: primary and secondary hypothyroidism, after operations for struma, as a result of radioactive iodine therapy (as replacement therapy).
Prevention of recurrence (re-formation) of nodular goiter after surgery for goiter with normal thyroid function.
Diffuse goiter with normal function.
As part of combination therapy in the treatment of hyperthyroidism with thyrostatics after achieving its normal function.
Malignant tumor of the thyroid gland, mainly after surgery to suppress tumor recurrence and as a replacement therapy.
- Increased individual sensitivity to the drug;
- untreated thyrotoxicosis;
- acute myocardial infarction;
- acute myocarditis;
- untreated adrenal insufficiency.
With caution, the drug should be prescribed for coronary artery disease (atherosclerosis, angina pectoris, myocardial infarction in the anamnesis), arterial hypertension, arrhythmia, diabetes mellitus, severe long-existing hypothyroidism, malabsorption syndrome (dose adjustment may be required).
Use in pregnancy and lactation
During pregnancy and breastfeeding, therapy with the drug prescribed for hypothyroidism should continue. During pregnancy, an increase in the dose of the drug is required due to an increase in the level of thyroxine-binding globulin. The amount of thyroid hormone secreted with breast milk during lactation (even when treated with high doses of the drug) is not enough to cause any disturbances in the child.
The use of the drug in combination with thyrostatic drugs during pregnancy is contraindicated, because taking levothyroxine may require an increase in the doses of thyrostatics. Since thyrostatics, unlike levothyroxine, can penetrate the placental barrier, the fetus may develop hypothyroidism.
During breastfeeding, the drug should be taken with caution, strictly in recommended doses under the supervision of a doctor.
With hypothyroidism caused by a lesion of the pituitary gland, it is necessary to find out whether there is simultaneously a deficiency of the cortex. Adrenal. In this case, GCS replacement therapy should be started before starting treatment of hypothyroidism with thyroid hormones in order to avoid the development of acute adrenal insufficiency.
Influence on the ability to drive vehicles and control mechanisms
The drug does not affect the ability to drive vehicles and work that requires increased concentration of attention.
Levothyroxine enhances the effect of indirect anticoagulants, which may require a reduction in their dose.
The use of tricyclic antidepressants with levothyroxine can lead to an increase in the action of antidepressants.
Thyroid hormones can increase the need for insulin and oral hypoglycemic medications. More frequent monitoring of blood glucose levels is recommended to be carried out during the periods of the beginning of treatment with levothyroxine, as well as when changing the dose of the drug.
Levothyroxine reduces the effect of cardiac glycosides. With the simultaneous use of colestyramine, colestipol and aluminum hydroxide reduce the plasma concentration of levothyroxine by inhibiting its absorption in the intestine.
With simultaneous use with anabolic steroids, asparaginase, tamoxifen, pharmacokinetic interaction at the level of binding to the protein is possible.
With simultaneous use with phenytoin, salicylates, clofibrate, furosemide in high doses, the content of levothyroxine and T4, unbound with blood plasma proteins, increases.
Somatotropin with simultaneous use with levothyroxine can accelerate the closure of epiphyseal growth zones.
Taking phenobarbital, carbamazepine and rifampicin can increase the clearance of levothyroxine and require an increase in dose.
Estrogens increase the concentration of the thyroglobulin-related fraction, which can lead to a decrease in the effectiveness of the drug.
Amiodarone, aminoglutethimide, PASK, ethionamide, antithyroid drugs, beta-blockers, carbamazepine, chloral hydrate, diazepam, levodopa, dopamine, metoclopramide, lovastatin, somatostatin affect the synthesis, secretion, distribution and metabolism of the drug.
Symptoms characteristic of thyrotoxicosis: palpitations, heart rhythm disturbance, heart pain, anxiety, tremor, sleep disturbance, excessive sweating, decreased appetite, weight loss, diarrhea.
Treatment: it may be recommended to reduce the daily dose of the drug, a break in treatment for several days, the appointment of beta-blockers. After the disappearance of side effects, treatment should be started with caution with a lower dose. Antithyroid drugs are not recommended.
Dosage and Administration
Inside, on an empty stomach, at least 30 minutes before breakfast. Daily dose of the drug establish and monitor individually on the basis of laboratory and clinical examination data.
As the accumulated experience shows, with a small body weight and in the presence of large nodular struma, a low dose is sufficient.
Unless otherwise prescribed, the following dosage recommendations apply:
with hypothyroidism of the thyroid gland, the initial daily dose for adults is 25-100 μg, then the dose is increased as prescribed by the doctor every 2-4 weeks by 25-50 μg until the maintenance daily dose is reached - 125-250 μg; children - 12.5-50 μg, with a long course of treatment, the dose is determined by the body weight and height of the child (from the approximate calculation from 100 to 150 μg of levothyroxine sodium per 1 m 2 body surfaces);
to prevent recurrence of goiter and with diffuse goiter in adults - 75-200 μg / day;
as part of combination therapy in the treatment of hyperthyroidism with thyrostatics - 50-100 μg / day;
in the treatment of a malignant tumor, the daily dose is 150-300 μg.
Allergic reactions (skin rash, itchy skin).
When used in excessively high doses - hyperthyroidism (change in appetite, dysmenorrhea, chest pain, diarrhea, tachycardia, arrhythmia, fever, tremor, headache, irritability, muscle cramps of the lower extremities, nervousness, sweating, difficulty falling asleep, vomiting, weight loss).
When used in insufficiently effective doses - hypothyroidism (dysmenorrhea, constipation, dryness, puffiness of the skin, headache, lethargy, myalgia, drowsiness, weakness, apathy, weight gain).
Store at a temperature not exceeding 25 °C.
Keep out of reach of children.
Shelf life 3 years.
- Dosage form
- 100 mcg
- Levothyroxine sodium
- Number of tablets
- INN Russian
- Левотироксин натрия
- Russian title