Minimum dose of thyroxine. Release form and composition

P N008963

Trade name of the drug: L-Thyroxine 50 Berlin-Chemie

International nonproprietary name:

Levothyroxine sodium

Dosage form:

pills

Compound:

Active substance: levothyroxine sodium - 0.05 mg.
Excipients: calcium hydrogen phosphate dihydrate - 15.95 mg, microcrystalline cellulose 16.00 mg, sodium carboxymethyl starch (type A) - 12.00 mg, dextrin - 6.80 mg, long-chain partial glycerides - 1.20 mg.

Description: round, slightly convex tablets, white or off-white with a slightly yellowish tint, scored on one side and embossed “50” on the other.

Pharmacological group: Thyroid remedy.

ATX code: H03AA01

Pharmacological properties
Pharmacodynamics
Synthetic levorotatory isomer of thyroxine. After partial conversion into triiodothyronine (in the liver and kidneys) and passage into the cells of the body, 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 need for oxygen in tissues, stimulates the metabolism of proteins, fats and carbohydrates, and increases the functional activity of the cardiovascular system and central nervous system.
In large doses, it inhibits the production of thyrotropin-releasing hormone of the hypothalamus and thyroid-stimulating hormone (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 for hypothyroidism appears after 3-5 days. Diffuse goiter decreases or disappears within 3-6 months.
Pharmacokinetics
When taken orally, levothyroxine sodium is absorbed almost exclusively in the upper small intestine. Up to 80% of the dose taken is absorbed.
Eating reduces the absorption of levothyroxine sodium. Maximum serum concentrations are achieved approximately 5-6 hours after oral administration. After absorption, more than 99% of the drug binds to serum proteins (thyroxine-binding globulin, thyroxine-binding prealbumin and albumin). In various tissues, approximately 80% of sodium levothyroxine is monodeiodinated 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 undergoes deamination and decarboxylation, as well as conjugation with sulfuric and glucuronic acids (in the liver). Metabolites are excreted by the kidneys and through the intestines. 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 is extended to 9-10 days.

Indications for use
- hypothyroidism;
- euthyroid goiter;
- as replacement therapy and for the prevention of goiter recurrence after resection of the thyroid gland;
- thyroid cancer (after surgical treatment);
- diffuse toxic goiter: after achieving a euthyroid state with antithyroid drugs (in the form of combination or monotherapy);
- as a diagnostic tool when performing a thyroid suppression test.

Contraindications
- hypersensitivity to the active substance or to any of the excipients included in the drug (see section Compound);
- untreated thyrotoxicosis;
- acute myocardial infarction, acute myocarditis;
- untreated adrenal insufficiency.

Carefully the drug should be prescribed for diseases of the cardiovascular system: ischemic heart disease (atherosclerosis, angina pectoris, history of myocardial infarction), arterial hypertension, arrhythmia, diabetes mellitus, severe long-term hypothyroidism, malabsorption syndrome (dose adjustment may be required).

Use during 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 content of thyroxine-binding globulin. The amount of thyroid hormone secreted in breast milk during lactation (even when treated with high doses of the drug) is not enough to cause any problems in the child.
The use of the drug in combination with antithyroid drugs during pregnancy is contraindicated, since taking levothyroxine sodium may require an increase in doses of antithyroid drugs. Since antithyroid drugs, unlike levothyroxine sodium, can cross the placenta, the fetus may develop hypothyroidism. During breastfeeding, the drug should be taken with caution, strictly in recommended doses under medical supervision.

Directions for use and doses
The daily dose is determined individually depending on the indications.
L-Thyroxine 50 Berlin-Chemie in a daily dose is taken orally in the morning on an empty stomach, or at least 30 minutes before meals, washing down the tablet with a small amount of liquid (half a glass of water) and without chewing.
When carrying out replacement therapy for hypothyroidism (in the absence of cardiovascular diseases), L-Thyroxine 50 Berlin-Chemie is prescribed in a daily dose of 1.6-1.8 mcg/kg body weight. In case of significant obesity, the calculation should be made on the “ideal weight”.

For infants and children under 3 years of age, the daily dose of L-Thyroxin 50 Berlin-Chemie is given 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-term hypothyroidism, treatment should be started with extreme caution, with small doses - 25 mcg / day, the dose is increased to maintenance at longer intervals - by 25 mcg / day every 2 weeks and the TSH concentration in the blood is determined more often. For hypothyroidism, L-Thyroxine 50 Berlin-Chemie is usually taken throughout life. For thyrotoxicosis, L-Thyroxin 50 Berlin-Chemie is used in complex therapy with antithyroid drugs after achieving a euthyroid state. In all cases, the duration of treatment with the drug is determined by the doctor.

For precise dosing of the drug, use the most suitable form of release of the drug L-Thyroxine Berlin-Chemie (50, 75, 100, 125 or 150 mcg).

Side effect
When used correctly under medical supervision, no side effects are observed.
If you are hypersensitive to the drug, allergic reactions may occur.

Overdose
In case of an overdose of the drug, symptoms characteristic of thyrotoxicosis are observed: tachycardia, cardiac arrhythmia, heart pain, anxiety, tremor, insomnia, hyperhidrosis, decreased appetite, weight loss, diarrhea, vomiting, headache, increased fatigue, muscle spasms. Depending on the severity of symptoms, the doctor may recommend reducing the daily dose of the drug, a break in treatment for several days, or prescribing beta-blockers. After side effects disappear, treatment should be started with caution at a lower dose. Antithyroid drugs are not recommended.

Interaction with other drugs
Levothyroxine sodium enhances the effect of indirect anticoagulants, which may require a reduction in their dose.
The use of tricyclic antidepressants with levothyroxine sodium may lead to increased effects of the antidepressants.
Thyroid hormones may increase the need for insulin and oral hypoglycemic agents. More frequent monitoring of blood glucose concentrations is recommended during the period of initiation of treatment with levothyroxine sodium, as well as when changing the dose of the drug.
Levothyroxine sodium reduces the effect of cardiac glycosides. With simultaneous use of cholestyramine, colestipol and aluminum hydroxide, they reduce the plasma concentration of levothyroxine sodium by inhibiting its absorption in the intestine.
When used simultaneously with anabolic steroids, asparaginase, tamoxifen, pharmacokinetic interaction is possible at the level of protein binding.
When used simultaneously with phenytoin, salicylates, clofibrate, furosemide in high doses, the content of levothyroxine sodium and T4 not bound to blood plasma proteins increases.
Somatotropin, when used simultaneously with levothyroxine sodium, can accelerate the closure of epiphyseal growth zones.
Taking phenobarbital, carbamazepine and rifampicin may increase the clearance of levothyroxine sodium and require an increase in dose.
Estrogens increase the concentration of the thyroglobulin-bound fraction, which may lead to a decrease in the effectiveness of the drug.
Amiodarone, aminoglutethimide, para-aminosalicylic acid (PAS), ethionamide, antithyroid drugs, beta-blockers, chloral hydrate, diazepam, levodopa, dopamine, metoclopramide, lovastatin, somatostatin affect the synthesis, secretion, distribution and metabolism of levothyroxine sodium.
Products containing soy may reduce the absorption of levothyroxine sodium (dose adjustment may be required).

special instructions
In case of hypothyroidism caused by damage to the pituitary gland, it is necessary to find out whether there is simultaneous insufficiency of the adrenal cortex. In this case, replacement therapy with glucocorticosteroids should be started before treatment of hypothyroidism with thyroid hormones is started in order to avoid the development of acute adrenal insufficiency.

The effect of the drug on the ability to drive vehicles and operate machinery
L-Thyroxine 50 Berlin-Chemie does not affect the ability to drive vehicles or work requiring increased concentration.

Release form
Tablets 50 mcg.
25 tablets per blister pack (blister) [PVC/PVDC/aluminum foil or aluminum foil/aluminum foil].
1, 2 or 4 blisters along with instructions for use are placed in a cardboard box.

Storage conditions
Store at a temperature not exceeding 25 °C.
Keep the medicine out of the reach of children!

Best before date
2 years.
Do not use after the expiration date indicated on the package!

Conditions for dispensing from pharmacies
On prescription.

Manufacturer
Berlin-Chemie AG
Glinker Veg 125
12489, Berlin
Germany

Address for filing claims
115162, Moscow, st. Shabolovka, house 31, building B.

Thyroxine is one of the ten drugs most often prescribed by doctors in the United States and in most Western European countries.

Most often it is used where there is a high prevalence of thyroid diseases due to iodine deficiency (in Germany, for example). Thyroxine is usually prescribed for suppressive or replacement therapy.

Replacement therapy: supporting proper metabolism in patients with hypothyroidism. If the treatment goes well, the symptoms of the disease disappear. The level of TSH and thyroid hormones should also be within normal limits.

Suppressive therapy: used in patients with nodular goiter, as well as in people with thyroid cancer after surgery, as well as treatment with radioactive iodine.

Thyroxine is one of the hormones secreted by the thyroid gland. It metabolizes lipids and reduces cholesterol. This is necessary for hypothyroidism - with this disease, cholesterol levels are greatly increased.

The amount of thyroxine must be checked using a blood test. Elevated levels of the hormone are often observed during pregnancy. Also, an increased amount of the hormone in the blood can be observed while taking certain medications.

How the drug works

Thyroxine, entering the liver and kidneys, is converted into triiodothyronine, then moves into the cells of the body. The drug affects the growth and development of all tissues, normalizes metabolism.

Small doses of medication: Thyroxine has a strong effect on fat and protein metabolism.

Average doses of the drug: Thyroxine stimulates development, growth, increases the need for oxygen in all tissues, stimulates the metabolism of fats, proteins and carbohydrates, and also improves the activity of the central nervous system and the cardiovascular system.

Large doses of the drug: Thyroxine inhibits the production of pituitary hormone and hypothalamic hormone.

The effect of taking the medication can be seen within 7-12 days. The effect of the drug after its withdrawal also lasts 7-12 days. The clinical effect of taking the medicine for hypothyroidism appears within 4-5 days. After 3-6 months, diffuse goiter disappears.

Pharmacokinetics

After administration, Thyroxine is absorbed in the small intestine (in the upper section). About 80% of the dose taken is absorbed. The absorption of the drug is prevented by food intake. The maximum effect of the hormone is observed within 6 hours after its administration.

After the drug is absorbed, 99% of Thyroxine binds to proteins. Metabolites are excreted through the intestines and kidneys. The half-life of Thyroxine is about 7 days.

Instructions: indications for use

Thyroxine is prescribed to patients for the following diseases:

• Rehabilitation after thyroid surgery.
• Hypothyroidism.
• Euthyroid goiter.
• For effective prevention of recurrence of goiter diseases after resection of the thyroid gland.
• Diagnosis during the thyroid suppression test.
• Diffuse toxic goiter.
• Myocarditis, myocardial infarction.
• Kidney failure.
• Thyrotoxicosis.

Contraindications

1. Hypersensitivity (allergy) to any components of the drug.
2. Myocarditis, myocardial infarction.
3. Kidney failure.
4. Thyrotoxicosis.
5. Diseases of the heart and blood vessels (dose adjustment is carried out).

How to take the drug

The dose for each patient is determined individually.

The medicine must be taken orally in the morning on an empty stomach, washed down with clean water.

During replacement therapy in people under 55 years of age without heart and vascular diseases, the daily dose of Thyroxine is from 1.6 to 1.8 mcg/kg.

For people over 55 years of age and with heart disease – 0.9 mcg/kg.

Instructions for starting replacement therapy for the treatment of hypothyroidism

Instructions for the treatment of congenital hypothyroidism

Patient age		Dose of the drug depending on body weight, µg/kg
0-6 months
6-12 months	From 50 to 75
	From 75 to 100
	From 100 to 150
Over 12 years old	From 150 to 200

Instructions

For children under three years of age, the daily dose of the medicine should be given at one time at least half an hour before the first meal. The tablet must be dissolved in a small amount of clean water immediately before use.

When treating hypothyroidism, Thyroxine must be taken for life.

Overdose

If the dose of medication is exceeded, the following symptoms may occur:

When the side effects disappear, taking Thyroxine should be started with small doses.

Taking medicines during pregnancy and while breastfeeding

When treating hypothyroidism, pregnant women must continue taking the drug, as well as during lactation and feeding.

The amount of the drug that is excreted in breast milk does not cause any disturbances in the child’s body. The medicine must be taken carefully, strictly following the recommendations for use given by the doctor.

Price of the drug and its analogues

L-Tirox - price about 200 rubles.

Bagotirox - price about 160 rubles.

Tivoral - price about 250 rubles.

Eutirox – price about 360 rubles.

The listed drugs are analogues of thyroxine. The price depends on the form of release and the manufacturer. To replace the drug with an analogue, you must consult your doctor.

L-thyroxine: instructions for use and reviews

L-thyroxine is a thyroid-stimulating drug, a thyroid hormone.

Release form and composition

The drug is produced in the form of tablets (10 pcs. in blister packs, 2, 3, 4, 5, 6, 8 or 10 packs in a cardboard box; 20 or 50 pcs. in polymer containers, 1 container in a cardboard box pack; 50 pcs in blister packs, 1, 2, 4, 5, 6, 8 or 10 packs in a cardboard box; 50 pcs in blisters, 1 blister in a cardboard box).

1 tablet contains the active substance: levothyroxine sodium - 50 or 100 mcg.

Pharmacological properties

Pharmacodynamics

The active component of L-Thyroxine is levothyroxine sodium - a synthetic levorotatory isomer of thyroxine, which in the kidneys and liver is partially converted into triiodothyronine, then passes into the body's cells and affects metabolism, development and tissue growth.

In small doses, the drug has an anabolic effect on fat and protein metabolism. In medium doses, it increases the oxygen demand of tissues, improves the functional activity of the central nervous system and cardiovascular system, stimulates growth and development by improving the metabolism of fats, carbohydrates and proteins. In high doses, levothyroxine sodium inhibits the production of thyroid-stimulating hormone from the pituitary gland and thyrotropin-releasing hormone from the hypothalamus.

The therapeutic effect develops within 7–12 days of taking the drug. The effect remains valid for the same number of days after its cancellation. For hypothyroidism, the clinical effect appears after 3–5 days. Diffuse goiter decreases or completely disappears within 3–6 months.

Pharmacokinetics

After entering the gastrointestinal tract, levothyroxine sodium is absorbed almost exclusively in the upper part of the small intestine. Absorption of the drug is about 80% of the dose taken. When eating at the same time, the absorption of the substance decreases.

The maximum concentration in the blood is reached approximately 5–6 hours after taking the tablet. Levothyroxine sodium is characterized by a very high (at least 99%) association with serum proteins - albumin, TSPA (thyroxine-binding prealbumin) and TSH (thyroxine-binding globulin). In various tissues, about 80% of the active substance of the drug is monodeiodinated with the formation of triiodothyronine (T 3) and inactive products. Metabolism of thyroid hormones occurs primarily in the kidneys, liver, muscles and brain. A small amount of the drug undergoes decarboxylation and deamination, as well as conjugation with sulfuric and glucuronic acids (in the liver).

The route of elimination of metabolites is through the intestines and kidneys. The half-life is 6–7 days, in patients with thyrotoxicosis – 3–4 days, in patients with hypothyroidism – 9–10 days.

Indications for use

• Euthyroid goiter;
• Hypothyroidism;
• The period after resection of the thyroid gland (to prevent goiter recurrence and as replacement therapy);
• Thyroid cancer (after surgical treatment);
• Diffuse toxic goiter (for monotherapy or as part of complex treatment after achieving a euthyroid state with thyreostatics);
• Carrying out a thyroid suppression test (as a diagnostic tool).

Contraindications

Absolute:

• Acute myocardial infarction, acute myocarditis;
• Untreated thyrotoxicosis;
• Untreated adrenal insufficiency;
• Hereditary lactase deficiency or lactose intolerance (impaired absorption of glucose and galactose);
• Hypersensitivity to levothyroxine.

Relative (L-thyroxine tablets must be taken with caution):

• Diseases of the cardiovascular system: arterial hypertension, arrhythmias, coronary heart disease (history of myocardial infarction, atherosclerosis, angina pectoris);
• Diabetes;
• Severe (long-term) hypothyroidism;
• Malabsorption syndrome (dose adjustment may be required).

Instructions for use of L-thyroxine: method and dosage

L-thyroxine tablets are taken orally in the morning on an empty stomach, at least 1/2 hour before meals, without chewing and with a small amount (1/2 glass) of water.

The daily dose of L-thyroxine is determined by the attending physician individually and depends on the indications.

For replacement therapy of hypothyroidism in patients under 55 years of age, in the absence of cardiovascular diseases, the recommended daily dose of L-thyroxine is 1.6-1.8 mcg/kg body weight. For patients over 55 years of age or with cardiovascular disease, the dose is determined at the rate of 0.9 mcg/kg body weight. Patients with severe obesity (BMI - body mass index ≥ 30 kg/m2) are calculated at the “ideal weight”.

At the initial stage of replacement therapy for hypothyroidism, the recommended dose of levothyroxine is:

• Patients without cardiovascular diseases under the age of 55 years: men – 100-150 mcg/day, women – 75-100 mcg/day;
• Patients over 55 years of age and/or with cardiovascular diseases: regardless of gender – 25 mcg/day with a gradual increase in dose (25 mcg at intervals of 2 months) until the level of thyroid-stimulating hormone (TSH) in the blood is normalized.

If symptoms from the cardiovascular system appear or worsen, the course of treatment for cardiovascular diseases should be adjusted.

• From birth to 1/2 year – 25-50 mcg/10-15 mcg/kg;
• From 1/2 to 1 year – 50-75 mcg/6-8 mcg/kg;
• From 1 year to 5 years – 75-100 mcg/5-6 mcg/kg;
• From 6 to 12 years – 100-150 mcg/4-5 mcg/kg;
• Over 12 years old – 100-200 mcg/2-3 mcg/kg.

• Therapy of euthyroid goiter – 75-200 mcg;
• Prevention of relapses after surgical treatment of euthyroid goiter – 75-200 mcg;
• Thyrotoxicosis (as part of complex therapy) – 50-100 mcg;
• Thyroid cancer (for suppressive therapy) – 150-300 mcg;
• Carrying out a thyroid suppression test - 3-4 weeks before the test - 75 mcg, 1-2 weeks before the test - 150-200 mcg.

For children from birth to 3 years of age, the daily dose of levothyroxine is given 1/2 hour before the first feeding (in one dose). Immediately before use, the tablet must be dissolved in water until a thin suspension is formed.

In case of hypothyroidism, L-thyroxine is usually taken throughout life. For the treatment of thyrotoxicosis, the drug is used in combination with antithyroid drugs after achieving a euthyroid state. The duration of levothyroxine therapy for any condition/disease is determined by the attending physician.

Side effects

When using L-thyroxine in compliance with all recommendations and under medical supervision, no side effects were observed.

In case of hypersensitivity to levothyroxine, allergic reactions are possible. Other side effects can only develop with an overdose of the drug.

Overdose

In case of overdose, symptoms characteristic of thyrotoxicosis occur: increased sweating, heart pain, heart rhythm disturbances, rapid heartbeat, tremor, increased appetite, diarrhea, sleep disturbances, anxiety, weight loss.

Depending on the severity of overdose symptoms, the doctor may recommend a reduction in the daily dose of L-Thyroxine, a short (several days) break in taking it and/or the use of beta-blockers. After normalization of the condition, the drug should be started with caution, with a minimum dose.

special instructions

In the case of hypothyroidism caused by damage to the pituitary gland, a diagnosis should be made and find out whether there is simultaneous insufficiency of the adrenal cortex. If the result is positive, it is necessary to begin replacement therapy with GCS (glucocorticosteroids) before taking thyroid hormones for the treatment of hypothyroidism in order to avoid the development of acute adrenal insufficiency.

The concentration of TSH in the blood should be periodically monitored; an increase in this indicator indicates an insufficient dose of L-thyroxine.

Levothyroxine does not affect the concentration of attention and the speed of psychomotor reactions necessary to control complex mechanisms and vehicles.

Use during pregnancy and lactation

Therapy for hypothyroidism during pregnancy and lactation must be continued. During pregnancy, the level of TSH increases, so an increase in the dose of L-Thyroxine is required.

The use of sodium levothyroxine during pregnancy is contraindicated in combination with antithyroid drugs, since their dose may need to be increased while taking L-Thyroxine. In addition, unlike levothyroxine sodium, antithyroid drugs can penetrate the placenta, which may result in the development of hypothyroidism in the fetus.

The amount of thyroid hormone that is excreted in breast milk (even when taking the drug in high doses) is small, so it is not capable of causing any problems in the child. However, breastfeeding women should undergo treatment under the supervision of a doctor, strictly adhering to the recommendations.

Use in childhood

According to the instructions, L-Thyroxine is approved for use in pediatrics in accordance with the dosage regimen according to age.

Use in old age

L-Thyroxine is used according to indications in elderly patients in accordance with the doctor's recommendations.

Drug interactions

Mutual influence of the following substances/drugs and levothyroxine when used simultaneously:

• Insulin and oral hypoglycemic drugs - their dose may need to be increased (when starting therapy with levothyroxine sodium, as in the case of changing the dosage regimen, blood glucose concentrations should be checked more frequently);
• Indirect anticoagulants, tricyclic antidepressants – their effect is enhanced (dose reduction may be required);
• Colestipol, cholestyramine, aluminum hydroxide - reduce the concentration of levothyroxine sodium in the blood plasma due to a decrease in the rate of its absorption in the intestine;
• Anabolic steroids, asparaginase, tamoxifen - there is a possibility of pharmacokinetic interaction at the level of protein binding;
• Cardiac glycosides – their effectiveness decreases;
• Salicylates, clofibrate, furosemide (in high doses), phenytoin - increase the levels of sodium levothyroxine not bound to proteins and free thyroxine (T4) in the blood plasma; phenytoin reduces the volume of levothyroxine bound to proteins by 15%, T4 concentration by 25%;
• Estrogen-containing drugs – increase the amount of thyroxine-binding globulin, which may increase the need for levothyroxine in some patients;
• Somatotropin – possible acceleration of closure of epiphyseal growth zones;
• Phenobarbital, carbamazepine and rifampicin - may increase the clearance of levothyroxine sodium, which may result in an increase in its dose;
• Aminoglutethimide, amiodarone, para-aminosalicylic acid (PAS), antithyroid drugs, β-blockers, ethionamide, carbamazepine, chloral hydrate, levodopa, diazepam, dopamine, metoclopramide, somatostatin, lovastatin - affect the metabolism and distribution of L-thyroxine.

Analogs

Analogs of L-Thyroxine are: Bagotyrox, Levothyroxine, Eutirox, L-Thyroxine 50 Berlin-Chemie, L-Thyroxine 75 Berlin-Chemie, L-Thyroxine 100 Berlin-Chemie, L-Thyroxine 150 Berlin-Chemie.

Terms and conditions of storage

Store in a dry place, protected from light, out of reach of children, at a temperature not exceeding 25 °C.

Shelf life – 3 years.

L-thyroxine is a synthetic analogue of thyroid hormones, a thyroid-stimulating drug that helps normalize the hypofunction of the endocrine glands. The drug is prescribed for diseases of the thyroid gland.

The daily dose of L-thyroxine is selected depending on the indications for use, age, and the presence of concomitant disorders.

Composition, release form

The active ingredient is levothyroxine sodium.

The drug is available in pharmacies in the form of tablets for internal use in the following dosages:

• L-thyroxine 50 Berlin-chemi.
• L-thyroxine 75 Berlin-chemi.
• L-thyroxine 100 Berlin-chemi.
• L-thyroxine 125 Berlin-chemi.

pharmachologic effect

Levothyroxine is a synthetic analogue of thyroid hormones.

• The mechanism of action of L-thyroxine is due to the fact that the active component is partially converted into T3 in the liver and kidneys and affects the processes of growth, development, and metabolism.
• Shows moderate anabolic properties when used in small dosages.
• Use in a high dose inhibits the production of thyrotropin-releasing hormones of the hypothalamus and thyroid-stimulating hormones of the pituitary gland.

The therapeutic effect is observed no earlier than 72 hours after taking the tablets. The half-life is up to 1 week.

How to apply it correctly?

Treatment is possible only under the supervision of a doctor, who selects the dosage, frequency and duration of use of the drug individually for each patient. The calculation of the dose of L-thyroxine also depends on the patient’s body weight.

The recommended daily dose is taken half an hour before meals, on an empty stomach, without chewing, with a sufficient amount of water. The tablets have scoring notches, which allows you to divide the drug, if necessary.

• Hypothyroidism, thyroidectomy: lifelong treatment.
• Adjuvant therapy for hyperthyroidism: depending on the duration of use of thyreostatic drugs.
• Euthyroid goiter: from six months to 24 months. If during this time the expected pharmacological effect is not achieved, another treatment method is considered.
• Prevention of goiter relapse: several months - lifelong treatment.
• : from 1 month to 7 weeks. The dosage is reduced gradually over 2 weeks.

Recommendations regarding the dosage regimen are for informational purposes only. The doctor can adjust the dosage, frequency, and duration of treatment with the drug depending on the effect, tolerability, and individual characteristics of the patient’s body.

Hypothyroidism	- Women with normal functioning of the cardiovascular system: 75-100 mcg per day. Men with normal functioning of the cardiovascular system: 100-150 mcg per day. Patients over 55 years of age, persons with cardiovascular dysfunction: 25 mcg per day. After 8 weeks, the dose may be doubled. Subsequently, the dose is increased by 25 mcg every 8 weeks until thyrotropin normalizes. In case of dysfunction of the heart and blood vessels, the doctor must reconsider the treatment regimen and select drugs for symptomatic treatment of emerging cardiovascular disorders.
Congenital hypothyroidism	- The doctor selects the dosage individually. The patient's age is taken into account.
Childhood	- Daily dose for patients under 6 months: 25-50 mcg. 6-12 months: 50-75 mcg per day. 1-5 years: 75-100 mcg per day. 6 years and older: 100-150 mcg per day. 12 years and older: 100-200 mcg per day. When treating infants and children under 36 months, the daily dose should be given in one dose 30 minutes before the first feeding. The drug must first be diluted in water until a light suspension is formed.
Weight loss	- 50 mcg per day, divided into several doses in the morning. Additionally, beta-blockers are used. Gradually increase the dose to 150-300 mcg per day, divided into 3 doses, the last of which is carried out before 6 pm. The dose is reduced if undesirable side reactions develop.

If a repeated course of treatment is necessary, take a break of up to 1 month.

Indications for use

Separate indications for use are presented for each dosage.

L-thyroxine 50	- Benign neoplasms affecting the thyroid gland. Auxiliary thyreostatic treatment of hyperthyroidism. Replacement treatment for decreased thyroid function. Preventive treatment of goiter after resection.
L-thyroxine 100	Indications are the same as for dosage 50 + additionally: Diagnosis by testing thyroid suppression. Replacement and suppressive treatment of malignant neoplasms of the thyroid gland (history of thyroidectomy).
L-thyroxine 125, 150	- Hypothyroidism. Euthyroid goiter. Prevention of goiter recurrence. Thyrostatic and replacement treatment of malignant tumors of the thyroid glands.
L-thyroxine 75	- Auxiliary thyreostatic treatment of hyperthyroidism. The remaining indications are the same as for dosages 125, 150

Contraindications

• In case of a hypersensitivity reaction.
• Thyrotoxicosis.
• Increased concentrations of thyrotropin of various origins (and lack of treatment).
• Acute myocardial infarction, pancarditis and myocarditis.
• Insufficiency of the adrenal cortex and pituitary insufficiency (and the lack of their therapy).

During pregnancy, L-thyroxine cannot be combined with medications that exhibit thyreostatic properties.

Side effects of L-thyroxine

If the recommendations regarding the dosage regimen are followed, the drug is well tolerated. If the dosage is not suitable for the patient, then adverse reactions from taking L-thyroxine are possible in the cardiovascular, nervous, reproductive systems, digestive tract, skin, as well as the development of thyrotoxicosis.

Increased sweating, fever may be felt, body temperature rises, the menstrual cycle is disrupted, body weight decreases, cramps and weakness develop.

If adverse reactions develop, the dose is reduced or the use of the drug is discontinued for 24-48 hours. Long-term the use of L-thyroxine in a high dose is fraught with serious complications from the cardiovascular system, up to death.

During pregnancy and breastfeeding

There is no reliable information confirming the absolute safety of using L-thyroxine during pregnancy. The drug can only be prescribed by a doctor based on objective indications, taking into account the benefit/risk ratio.

During drug therapy, thyroid hormones do not penetrate into breast milk in quantities that can provoke thyrotoxicosis in a child. During lactation, the drug is used in strict accordance with the doctor's instructions regarding the dosage regimen.

Overdose

In case of an overdose of L-thyroxine, complaints of the following symptoms may occur:

• Increased pulse and heart rate, angina attacks.
• Increased anxiety, sweating, temperature, heat.
• Arrhythmia, sleep disturbances, development of tremor.
• Development of vomiting, diarrhea, cramps, headache, weakness.
• Loss of body weight, disruption of the menstrual cycle.

The use of the drug is stopped and control diagnostics are carried out.

Interaction with other drugs

It is necessary to take into account possible drug interactions of L-thyroxine with other groups of medications:

Antidiabetic drugs	- Reduced effectiveness of drugs in this group. It is necessary to monitor glucose levels more often at the beginning of therapy and when adjusting doses.
Barbiturates, carbamazepine	- Increased hepatic clearance of L-thyroxine.
Cholestyramine, colestipol, colesevelam	- Inhibition of absorption of the active substance L-thyroxine. An interval of at least 4-5 hours between taking medications is required.
Soy-based preparations, soy diet	- L-thyroxine dose adjustment may be required. Soy inhibits intestinal absorption of the active component L-thyroxine.
Preparations based on aluminum (antacids, sucralfate), iron, calcium carbonate	- Reduced effectiveness of L-thyroxine. L-thyroxine is taken no earlier than 120 minutes before using the described medications.
Glucocorticosteroids, amiodarone, iodine-based drugs	- Suppression of the conversion of the hormone T4 to T3. The likelihood of developing hyper-/hypothyroidism. Particular caution when treating patients with goiter of unknown origin.
Phenytoin	- Promotes displacement of the active component L-thyroxine from the blood plasma. It is necessary to constantly monitor thyroid hormone levels.
Estrogens	- An increase in the dose of L-thyroxine may be required.
Salicylates, furasemide (doses over 250 mg), dicumarol	- Displacement of the active component L-thyroxine.
Protease inhibitors (indinavir, lopinavir, ritonavir)	- Affect the concentration of the active substance L-thyroxine. It is necessary to regularly monitor thyroid hormone levels and adjust the concentration of L-thyroxine, if necessary.
Coumarin derivatives	- Anticoagulants increase their effect, increasing the risk of hemorrhages and gastrointestinal bleeding. The risk group consists of elderly patients. It is necessary to monitor laboratory parameters of coagulation and adjust the dose of drugs, if necessary.

Analogs

As analogues of L-thyroxine, the doctor may suggest the use of Eutirox, Levothyroxine, Bagotirox, Thyro-4, L-Thyroc.

Storage conditions

The drug is stored in a place inaccessible to children, observing the temperature regime: no more than 25 degrees.

L-Thyroxine is a drug of synthetic origin, which in its composition is a left-handed isomer of thyroxine. Its structure almost completely replicates the thyroid hormones. In small doses, this drug has an anabolic effect, and in medium doses it stimulates the growth of muscle mass and accelerates the process of burning fat. Over time, the components of L-Thyroxine in the body are broken down in the liver or kidneys into triiodothyronine, which also speeds up the process of fat metabolism. It should be noted that the active substances increase the cells’ need for oxygen, which is why the lipid layer begins to break down. L-Thyroxine instructions for use will help solve your questions and can significantly speed up metabolism.

Indications for use of L-Thyroxine

L-Thyroxine is a fairly powerful drug that should be prescribed by the attending physician. Despite this, many people use it as an aid in the process of losing extra pounds. However, this drug should be used in the following cases:

• Hypothyroidism of various nature.
• Deficiency of thyroid hormones.
• Recurrence of diffuse goiter.
• Prevention after resection surgery.
• Additional therapy for thyrotoxicosis.
• Euthyroid state.
• Euthyroid goiter is benign in nature.
• Thyroid cancer.
• Autoimmune thyroiditis.
• Suppression of thyroid function.
• Graves' disease.

pharmachologic effect

L-Thyroxine is a synthetic levorotatory isomer of thyroxine. Its action is identical to the naturally occurring thyroid hormone. In small doses it has an anabolic effect. In medium doses, it stimulates the growth and development of the body, increases the need for synthetic levorotatory isomer of thyroxine. After partial conversion into triiodothyronine (in the liver and kidneys) and passage into the cells of the body, 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 need for oxygen in tissues, stimulates the metabolism of proteins, fats and carbohydrates, and increases the functional activity of the cardiovascular system and 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 persists after discontinuation of the drug. The clinical effect for hypothyroidism appears after 3-5 days. Diffuse goiter decreases or disappears within 3-6 months. tissues in oxygen, stimulates the metabolism of proteins, fats and carbohydrates, the activity of the cardiovascular system and the central nervous system. In high doses, it inhibits the production of thyrotropin-releasing hormone of the hypothalamus and thyroid-stimulating hormone of the pituitary gland.
After the start of therapy, the effect occurs within 3-5 days.

L-Thyroxine instructions for use

The exact dosage and frequency of use should be determined by a physician based on diagnostic tests. Among the generally accepted rules, it is necessary to highlight that the drug should be taken in the morning, at least half an hour before the first meal. The tablet should be taken with plenty of clean water and should not be chewed. The drug can be used as replacement therapy for hypothyroidism in people under 55 years of age if they do not have any cardiovascular diseases. In this case, the dose of the substance should not exceed 1.8 mcg/kg body weight. For patients older than this age, the concentration of the active substance is reduced to 1 mcg/kg body weight. When treating newborns, the following dosages are available:

When treating euthyroid goiter, the daily dose should be in the range of 75-200 mcg. Before surgery or to prevent this disease, a person is prescribed 75 mcg of the drug once a day for 2 weeks. For complex therapy of thyrotoxicosis, take 50-100 mcg of L-Thyroxine per day. The largest amount of the drug - 150-300 mcg per day - is prescribed for thyroid cancer.

Today L-Thyroxine is available in the following dosages: 20/75/100/125/150 mcg. This makes the product more convenient to use. It should be noted that the medicine must be taken with extreme caution. It is best to start with small doses - about 25 mcg per day. Gradually, the concentration of the active substance can be increased. The duration of treatment is usually determined by the doctor, however, in case of hypothyroidism, therapy with this drug is necessary throughout life.

Treatment is carried out with extreme caution in newborns and children under 3 years of age. The drug should be taken 30 minutes before feeding. For more convenient use, the tablet is dissolved in a small amount of water, and then given to the child to drink. Remember that therapy with this drug must be constantly monitored by the attending physician. It should be noted that L-Thyroxine instructions for use require mandatory reading.

Pharmacokinetics

When taken orally, levothyroxine sodium is absorbed almost exclusively in the upper small intestine. Up to 80% of the dose taken is absorbed. Eating reduces the absorption of levothyroxine sodium. Cmax is reached approximately 5-6 hours after oral administration. After absorption, more than 99% of the drug binds to serum proteins (thyroxine-binding globulin, thyroxine-binding prealbumin and albumin). Approximately 80% of levothyroxine sodium is monodeiodinated in various tissues to form triiodothyronine (T3) and inactive products. Thyroid hormones are metabolized mainly in the liver, kidneys, brain and muscles. A small amount of the drug undergoes deamination and decarboxylation, as well as conjugation with sulfuric and glucuronic acids (in the liver). Metabolites are excreted by the kidneys and through the intestines. 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 is extended to 9-10 days.

Contraindications to treatment with L-Thyroxine

Despite the fact that L-Thyroxine is a fairly safe drug, it still has a number of contraindications. For this reason, you should tell your doctor in advance about your chronic diseases so that the specialist can evaluate the possibility of treating thyroid disease with this particular remedy. Contraindications for the use of L-Thyroxine include:

• Adrenal insufficiency.
• Acute myocardial infarction.
• Acute myocarditis.
• Hypersensitivity to the components of the product.
• Galactose intolerance.
• Impaired absorption of lactose and glucose.

L-Thyroxine tablets should be used with extreme caution in case of diseases of the cardiovascular system, ischemia, atherosclerosis, myocardial infarction, angina pectoris, arterial hypertension, diabetes mellitus, long-term hypothyroidism, malabsorption syndrome, after resection. We strongly recommend that you find out what the instructions for use describe L-Thyroxine.

Side effects

If all precautions and doctor's recommendations are followed, side effects from the use of L-Thyroxine occur extremely rarely. In some cases, a person may face problems such as hair loss, thinning nail plates, impaired kidney function, increased appetite and weight gain. In very rare cases, seizures may occur, but this only occurs in people who suffer from diseases of the nervous system.

When using excessive doses of L-Thyroxine, symptoms of hyperthyroidism may appear. This is usually characterized by arrhythmia, tachycardia, disruption of sleep and wakefulness, tremors of the limbs, weight loss, diarrhea, vomiting, and possible angina attacks. Allergic dermatitis occurs extremely rarely. If side effects occur, it is necessary to reduce the dose of the active substance and be sure to consult a doctor.

Overdose

In case of an overdose of the drug, symptoms characteristic of thyrotoxicosis are observed:

• heartbeat;
• heart rhythm disturbance;
• heartache;
• anxiety;
• tremor;
• sleep disturbance;
• increased sweating;
• increased appetite;
• weight loss;
• diarrhea.

Depending on the severity of symptoms, the doctor may recommend reducing the daily dose of the drug, a break in treatment for several days, or prescribing beta-blockers. After side effects disappear, treatment should be started with caution at a lower dose.

special instructions

In case of hypothyroidism caused by damage to the pituitary gland, it is necessary to find out whether there is simultaneous insufficiency of the adrenal cortex. In this case, replacement therapy with glucocorticosteroids should be started before treatment of hypothyroidism with thyroid hormones is started in order to avoid the development of acute adrenal insufficiency.

It is recommended to periodically determine the concentration of thyroid-stimulating hormone (TSH) in the blood, an increase in which indicates an insufficient dose.The drug does not affect activities related to driving vehicles and operating machinery.

Reception during pregnancy and lactation

During pregnancy and lactation (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 in breast milk during lactation (even when treated with high doses of the drug) is not enough to cause any problems in the child.

The use of the drug in combination with thyreostatic drugs during pregnancy is contraindicated, because Taking levothyroxine may require increasing doses of thyreostatics. Since thyreostatics, 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 medical supervision.