L-Thyroxine 75 mcg 100 tablets, Levothyroxine sodium

75 mcg

Active ingredient: levothyroxine sodium - 0.075 mg.

Excipients: calcium hydrogen phosphate 2-aqueous; microcrystalline cellulose; carboxymethyl starch sodium salt, type A; dextrin: long-chain partial glycerides.

Pharmacodynamics

Synthetic 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 stimulates growth and development, increases the need for tissues in oxygen, stimulates metabolism of proteins, fats and carbohydrates, increases the functional activity of the cardiovascular system and the central nervous system.

In large doses, it inhibits the production of thyrotropin-releasing hormone of the hypothalamus and thyroid-stimulating hormone 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.

Pharmacokinetics

When taken orally, levothyroxine is absorbed almost exclusively in the upper part of the small intestine. Up to 80% of the dose of the drug is absorbed. Food intake reduces the absorption of levothyroxine.

The maximum concentration in the blood serum is reached approximately 5-6 hours after ingestion. After absorption, more than 99% of the drug binds to serum proteins (thyroxine-binding globulin, thyroxine-binding prealbumin and albumin).

In various tissues, monodeiodation of approximately 80% of levothyroxine occurs to form triiodothyronine (T ₃ ) and inactive products. Thyroid hormones are metabolized mainly in the liver, kidneys, brain and muscles.

A small amount of the drug is subjected to deamination and decarboxylation, as well as conjugation with sulfuric and glucuronic acids (in the liver).

Metabolites are excreted in the urine and bile. The half-life of the drug is 6-7 days. With thyrotoxicosis, the half-life is shortened to 3-4 days, and with hypothyroidism, it lengthens to 9-10 days.

• hypothyroidism;
• euthyroid goiter;
• as a replacement therapy and for the prevention of recurrence of goiter after resection of the thyroid gland;
• thyroid cancer (after surgical treatment);
• diffuse toxic goiter: after reaching a euthyroid state with thyrostatics (in the form of combined or monotherapy);
• as a diagnostic tool for the thyroid suppression test.

• Increased individual sensitivity to the drug;
• Untreated thyrotoxicosis;
• Acute myocardial infarction, acute myocarditis;
• Untreated adrenal insufficiency.

With caution, the drug should be prescribed for diseases of the cardiovascular system: 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).

The daily dose is determined individually depending on the indications. L-Thyroxine in a daily dose is taken orally in the morning on an empty stomach, at least 30 minutes before meals, washed down with a tablet with a small amount of liquid (half a glass of water) and not chewing.

When conducting replacement therapy for hypothyroidism in patients younger than 55 years in the absence of cardiovascular diseases, L-thyroxine is prescribed in a daily dose of 1.6-1.8 μg / kg of body weight; in patients older than 55 years or with cardiovascular diseases - 0.9 μg / kg body weight. With significant obesity, the calculation should be made on the "ideal weight".

For the exact dosage of the drug, use the most appropriate dosage of the drug.

Infants receive a daily dose of L-thyroxine in one dose 30 minutes before the first feeding. The tablet is dissolved in water to a thin suspension, which is prepared immediately before taking the drug.

In patients with severe long-existing hypothyroidism, treatment should be started with extreme caution, with small doses - from 25.0 μg / day, the dose is increased to maintenance at longer intervals - by 25.0 μg / day every 2 weeks and the level of TSH in the blood is more often determined.

In hypothyroidism, L-thyroxine is usually taken throughout life.

In thyrotoxicosis, L-thyroxine is used in complex therapy with thyrostatics after reaching a euthyroid state. In all cases, the duration of treatment with the drug is determined by the doctor.

At proper use under the supervision of a doctor side effects are not observed.

With hypersensitivity to the drug, allergic reactions may be observed.

At a temperature not exceeding 25 ° C.

Keep the drug out of the reach of children!