L-thyroxine - instructions for use, dose, side effects, contraindications

Excipients: lactose (milk sugar) 75.0 mg, povidone (polyvinylpyrrolidone) 2.45 mg, magnesium stearate 0.5 mg, pregelatinized starch 5.0 mg, cellulose microcrystalline - 17.0 mg.

1 tablet of 100 μg contains:

Active substance: sodium levothyroxine 0.1 mg.

Excipients: lactose (milk sugar) 75.0 mg, povidone (polyvinylpyrrolidone) 2.4 mg, magnesium stearate - 0.5 mg, pregelatinized starch 5.0 mg, microcrystalline cellulose 17.0 mg.

Description:Tabhetki white or white with a creamy shade of color, flat-cylindrical, with a facet on both sides and risk from one side.

Pharmacotherapeutic group:thyroid

ATX: & nbsp

H.03.A.A Thyroid hormones

H.03.A.A.01 Levothyroxine sodium

Pharmacodynamics:

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

In small doses, it has an anabolic effect on protein and fat metabolism.

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

In large doses oppresses the production of thyrotropin-releasing hormone hypothalamus and thyroid-stimulating hormone of the pituitary gland.

Therapeutic effect is observed after 7-12 days, during the same time the action remains after drug discontinuation. The clinical effect with hypothyroidism is manifested in 3-5 days. Diffuse goiter decreases or disappears within 3-6 months.

Pharmacokinetics:

Ingestion levothyroxine sodium absorbed almost exclusively in the upper part of the small intestine. Absorbed up to 80% of the dose of the drug. The intake of food reduces the absorption of levothyroxine sodium. The maximum concentration in the serum is reached approximately 5-6 hours after ingestion.

After absorption, more than 99% of the drug binds to serum proteins (thyroxin-binding globulin, thyroxine-binding prealbumin and albumin). In various tissues, approximately 80% of levothyroxine sodium monideiodinated 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 is subjected to 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 period is shortened to 3-4 days, and with hypothyroidism it lengthens to 9-10 days.

Indications:

- 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 the euthyroid status with thyreostatics (in the form of combined or monotherapy);

- as a diagnostic tool in the test of thyroid suppression.

Contraindications:

- Increased individual sensitivity to the drug;

- untreated thyrotoxicosis;

- acute myocardial infarction, acute myocarditis;

- untreated adrenal insufficiency;

- hereditary intolerance to galactose, insufficiency of lactase or impaired absorption of glucose and lactose.

Carefully:

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

Pregnancy and lactation:

During pregnancy and breastfeeding, therapy with a 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 during treatment with high doses of the drug), not enough to cause any disorder in the child.

Application in pregnancy of the drug in combination with antithyroid drugs is contraindicated, since taking levothyroxine sodium may require an increase in the dose of antithyroid drugs. Since antithyroid drugs, unlike levothyroxine sodium, can penetrate the placenta, the fetus may develop hypothyroidism.

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

Dosing and Administration:

The daily dose is determined individually depending on the indications.

L-tiroxine in a daily dose is taken orally in the morning on an empty stomach, at least 30 minutes before meals, with a small amount of liquid (half a cup of water) and without chewing.

When carrying out substitution therapy for hypothyroidism in patients younger than 55 years with no cardiovascular disease L-roteroxin is prescribed in a daily dose of 1.6-1.8 μg / kg body weight; in patients older than 55 years of age or with cardiovascular diseases - 0.9 μg / kg body weight. With expressed obesity (BMI ≥ 30 kg / m²) The calculation should be done on the "ideal weight".

The initial stage of replacement therapy for hypothyroidism

Patients without cardiovascular disease younger than 55 years

- Initial dose:

women - 75-100 mcg / day,

men - 100-150 mcg / day

Patients with cardiovascular diseases or over 55 years of age

- The initial dose is 25 mcg per day

- Increase by 25 mcg with an interval of 2 months before the normalization of the TSH in the blood

- With the appearance or worsening of symptoms from the cardiovascular system, a correction of cardiovascular disease

Recommended doses of levothyroxine for the treatment of congenital hypothyroidism
Age	The daily dose of levothyroxine (μg)	The dose of levothyroxine in terms of body weight (μg / kg)
0-6 months	25-50	10-15
6-12 months	50-75	6-8
1-5 years	75-100	5-6
6-12 years old	100-150	4-5
> 12 years	100-200	2-3

Indications	Recommended doses (L-Tiroxin μg / day)
Treatment of euthyroid goiter	75-200
Prevention of relapse after surgical treatment of euthyroid goiter	75-200
In the complex therapy of thyrotoxicosis	50-100
Suppressive Thyroid Cancer Therapy	150-300
Thyroid suppression test		4 weeks before the test	For 3 weeks before the test	2 weeks before the test	1 week before the test
Thyroid suppression test	L-Thyroxine	75 mcg / day	75 mcg / day	150-200 mcg / day	150-200 mcg / day

Breast children and children under 3 let daily dose L-roteroxin is given at one time 30 minutes before the first feeding. The tablet is dissolved in water to a fine suspension, which is prepared immediately before taking the drug.

With hypothyroidism L-tiroxine is taken, as a rule, throughout life.

With thyrotoxicosis L-teroxin is used in complex therapy with antithyroid drugs after reaching the euthyroid status. In all cases, the duration of treatment with the drug is determined by the doctor.

Side effects:

When used correctly L-tiroxine under the supervision of a doctor, side effects are not observed.

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

The development of other side effects is caused by an overdose of the drug (see the section "Overdose").

Overdose:

When an overdose of the drug is observed symptoms typical of thyrotoxicosis: palpitation, heart rhythm disturbance, pain in the heart, anxiety, tremor, sleep disturbance, increased sweating, increased appetite, weight loss, diarrhea.Depending on the severity of symptoms, a doctor may recommend a reduction in 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 initiated with caution from a lower dose.

Interaction:

Levotiroksin sodium increases the effect of indirect anticoagulants, which may require a reduction in their dose.

The use of tricyclic antidepressants with levothyroxine sodium may lead to an increase in the action of antidepressants.

Thyroid hormones can increase the need for insulin and oral hypoglycemic drugs. More frequent monitoring of blood glucose concentration is recommended to be carried out at the time of initiation of treatment with levothyroxine sodium, as well as changing its dosage regimen.

Levothyroxine sodium reduces the action of cardiac glycosides.

With simultaneous application colestramine, colestipol and aluminum hydroxide reduce the plasma concentration of levothyroxine sodium due to inhibition of its absorption in the intestine.

When used simultaneously 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 non-protein-bound blood plasma levothyroxine sodium and thyroxine (T₄) .

Admission of estrogen-containing drugs increases the content of thyroxine-binding globulin, which may increase the need for sodium levothyroxine in some patients.

Somatotropin with simultaneous application with levothyroxine sodium can accelerate the closure of epiphyseal growth zones.

The intake of phenobarbital, carbamazepine and rifampicin can increase the clearance of levothyroxine sodium and require an increase in the dose.

Distribution and metabolism of the drug are affected amiodarone, aminoglutethimide, PASK, ethionamide, antithyroid drugs, beta-blockers, carbamazepine, chloral hydrate, diazepam, levodopa, dopamine, metoclopramide, lovastatin, somatostatin.

When used simultaneously with phenytoin, salicylates, furosemide (in high doses), clofibrate increases the concentration of the drug in the blood.

Phenytoin reduces the amount of levothyroxine bound to the protein and the concentration of T₄ by 15 and 25% respectively.

Special instructions:

When hypothyroidism, due to the pituitary lesion, it is necessary to find out whether there is a simultaneous insufficiency of the adrenal cortex. In this case, glucocorticosteroid replacement therapy should be started before thyroid hormone therapy begins to avoid hypothyroidism 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, the increase of which indicates the insufficiency of the dose.

Effect on the ability to drive transp. cf. and fur:

The drug does not affect the activities associated with driving vehicles and controlling mechanisms.

Form release / dosage:

Tablets, 50 and 100 mcg.

Packaging:

For 10, 50 tablets are placed in a contour mesh box made of a polyvinylchloride film and aluminum foil printed lacquered.

1, 2, 3, 4, 5, 6, 8 or 10 contour mesh packages together with the instruction for use are placed in a pack of cardboard.

Storage conditions:

Store in a dry, dark place at a temperature of no higher than 25 ° C.

Keep out of the reach of children.

Shelf life:

3 years.

Do not use after the expiration date.

Terms of leave from pharmacies:On prescription

Registration number:LSR-000295/10

Date of registration:25.01.2010

Expiration Date:Unlimited

The owner of the registration certificate:OZONE, LLC OZONE, LLC Russia

Manufacturer: & nbsp

OZONE, LLC Russia

Representation: & nbspOZONE LLC OZONE LLC Russia

Information update date: & nbsp05.12.2016

Illustrated instructions

Instructions

L-thyroxine (L-Thyroxin)