L-Thyroxine

 1 tablet levothyroxine sodium 75 mcg

Excipients:

calcium hydrogen phosphate dihydrate,

microcrystalline cellulose,

sodium carboxymethyl starch (type A),

dextrin,

partial chain glycerides.

Synthetic thyroid hormone preparation, levorotatory thyroxine isomer. After partial conversion to triiodothyronine (in the liver and kidneys) and transition to body cells, it affects the development and growth of tissues, and metabolism.

In small doses, it has an anabolic effect on protein and fat metabolism. In medium doses, it stimulates growth and development, increases the oxygen demand of tissues, stimulates the metabolism of proteins, fats and carbohydrates, and increases the functional activity of the cardiovascular system and central nervous system. In high doses, inhibits the production of TSHP of the hypothalamus and TSH of the pituitary gland.

The therapeutic effect is observed after 7-12 days, during the same time the effect persists 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

Suction

After oral administration, levothyroxine is absorbed almost exclusively from the upper small intestine. Absorbed up to 80% of the dose taken. Simultaneous eating reduces the absorption of levothyroxine. Serum Cmax is reached approximately 5-6 hours after ingestion.

Distribution

It binds to serum proteins (thyroxin-binding globulin, thyroxin-binding prealbumin and albumin) by more than 99%. In various tissues, approximately 80% of levothyroxine is monodeiodized to form triiodothyronine (T3) and inactive products.

Metabolism

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).

Breeding

Metabolites are excreted in the urine and bile.

T1 / 2 is 6-7 days.

Pharmacokinetics in special clinical cases

With thyrotoxicosis, T1 / 2 is shortened to 3-4 days, and with hypothyroidism lengthens up to 9-10 days.

Hypothyroid states of various etiologies (including those caused by surgical or drug exposure), prevention of relapse of nodular goiter after resection of the thyroid gland, diffuse euthyroid goiter; diffuse toxic goiter - after the creation of the euthyroid state by thyreostatics (in the form of combination or monotherapy); thyroid cancer after surgical treatment (in order to suppress tumor recurrence and as a replacement therapy), as a diagnostic tool during the thyroid suppression test.

As part of complex therapy: Graves disease, autoimmune thyroiditis.

During pregnancy and breastfeeding, therapy with sodium levothyroxine 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 thyroxin-binding globulin.

The amount of thyroid hormone secreted with breast milk (even during treatment with high doses of the drug) is not enough to cause any disturbances in the baby during breastfeeding.

Pregnancy is contraindicated in combination with thyreostatics. taking levothyroxine sodium may require an increase in the doses of thyreostatics. Since thyreostatics, unlike sodium levothyroxine, can penetrate the placenta, the fetus may develop hypothyroidism.

The FDA category of action on the fetus is A.

During breastfeeding, the drug should be taken with caution, strictly at the recommended doses, under the supervision of a doctor.

For infants and children up to 3 years of age, the daily dose of the drug L-Thyroxine Berlin-Chemie is given in one dose 30 minutes before the first feeding. The tablet is dissolved in water until a thin suspension is prepared immediately before taking the drug.

• Hypersensitivity;
• untreated thyrotoxicosis;
• acute myocarditis;
• acute myocardial infarction;
• high blood pressure;
• untreated adrenal cortex insufficiency (should be compensated before starting therapy).

• Tachycardia;
• heart rhythm disturbance;
• pain behind the sternum;
• tremor;
• anxiety;
• insomnia
• hyperhidrosis;
• weight loss;
• diarrhea;
• alopecia;
• impaired adrenal function (with pituitary or hypothalamic hypothyroidism);
• impaired renal function in children; 
• allergic reactions (skin rash, itching of the skin).

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 increased action of antidepressants.

Thyroid hormones can increase the need for insulin and oral hypoglycemic drugs. More frequent monitoring of blood glucose levels is recommended during periods 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, they reduce the plasma concentration of levothyroxine due to inhibition of its absorption in the intestine.

With simultaneous use with anabolic steroids, asparaginase, tamoxifen, pharmacokinetic interaction at the level of protein binding is possible.

With simultaneous use with phenytoin, salicylates, clofibrate, furosemide in high doses, the content of levothyroxine and T4 unbound from plasma proteins increases.

Growth hormone with simultaneous use with levothyroxine can accelerate the closure of epiphyseal growth zones.

Taking phenobarbital, carbamazepine and rifampicin may increase the clearance of levothyroxine and require an increase in dose.

Estrogens increase the concentration of the fraction associated with thyroglobulin, 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.

The daily dose is determined individually depending on the indications.

A daily dose of L-thyroxine Berlin-Chemie is taken orally in the morning on an empty stomach, at least 30 minutes before a meal, drinking a tablet with a small amount of liquid (half a glass of water) and not chewing.

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

Initial stage of substitution therapy for hypothyroidism Patients without cardiovascular disease under 55 years of age Initial dose: 
women 50-100 mcg / day,
men 50-150 mcg / day Patients with cardiovascular disease or older than 55 years old Initial dose 25 mcg / day.
Increase by 25 μg with an interval of 2 months until the normalization of TSH level in the blood.
If cardiovascular symptoms appear or worsen, correct the treatment of cardiovascular diseases. Recommended doses of thyroxine for the treatment of congenital hypothyroidism 156–24 months for surgical treatment of euthyroid goiter50-200V for complex therapy of thyrotoxicosis50-100Suppressive therapy for thyroid cancer150-300Tyroid suppression test4 weeks before test 3 weeks before test 2 weeks before test 1 week before test

For accurate dosing of the drug, the most suitable dosage of the L-Thyroxine Berlin-Chemie drug (50, 75, 100, 125 or 150 mcg) should be used.

In severe long-term existing hypothyroidism, treatment should be started with extreme caution, from small doses - from 25 mcg / day, the dose is increased to a maintenance dose at longer time intervals - by 25 mcg / day every 2 weeks, and the level of TSH in the blood is more often determined. With hypothyroidism, L-Thyroxine Berlin-Chemie is taken, as a rule, throughout life.

With thyrotoxicosis, L-thyroxine Berlin-Chemie is used in combination therapy with thyreostatics after reaching the euthyroid state. In all cases, the duration of drug treatment is determined by the doctor.

Symptoms characteristic of thyrotoxicosis: palpitations, heart rhythm disturbances, heart pain, anxiety, tremors, sleep disturbances, increased sweating, decreased appetite, weight loss, diarrhea.

Treatment: a  decrease in the daily dose of the drug, a break in treatment for several days, the appointment of beta-blockers may be recommended. After the side effects disappear, treatment should be started with caution with a lower dose. Antithyroid drugs are not recommended.

With hypothyroidism due to damage to the pituitary gland, it is necessary to find out whether there is at the same time insufficiency of the adrenal cortex. In this case, GCS replacement therapy should be started before treatment of hypothyroidism with thyroid hormones begins 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 requiring increased concentration of attention.

Pills