"L-thyroxine" – a drug that allows you to maintain the normal operation of the body with hypothyroidism. It is a synthetic means of the analogue of thyroxine, which is in the liver and kidneys is partly converted into triiodothyronine by acting in cells of the body, affects metabolism, the development of tissues and their growth.

Pharmacological effects and pharmacokinetics

When used in small doses, the drug has anabolic effect on the metabolism of fats and proteins. Average doses of the drug contributed to the intensification of the processes of growth and development, protein, fat and carbohydrate metabolism. In such amounts the drug improves the functioning of the CNS and the cardiovascular system. Taking large doses of drugs leads to the inhibition of production of TSH and TRH.

Therapeutic effect can be achieved through 7-12 days of the reception facilities "L-thyroxine". Reviews indicate that after discontinuation of the drug the effect lasts for the same time. For the manifestation of clinical effect takes 3-5 days to reduce diffuse goiter is 3-6 months.

When the penetration into the body is absorbed up to 80 % of "L-thyroxine". If the drug is used in conjunction with food, its absorption is getting worse. The drug is well associated serum protein (more than 99 %). In tissues montelaterone approximately 80% of levothyroxine, as a result of this process formed triiodothyronine and inactive products. Metabolism of thyroid hormones occurs mainly in the kidney, liver, muscle, brain. In the liver, a small part of the drug undergoes decarboxylation and deamination, and conjugation with glucuronic and sulphuric acids. Metabolites are removed from the body with jelchew and urine.

In some cases, use of tool "L-thyroxine"? Reviews show the effectiveness of this drug in hypothyroidism resulting from some violations (insufficient number of thyroid, thyroid cancer, benign euthyroid goiter).

"L-thyroxine" is often used to test the results of which revealed thyroid function, for complex treatment of autoimmune thyroiditis and graves disease.

The drug is indicated for hypothyroidism its treatment during pregnancy, and thyrotoxicosis (after achieving euthyroid state) as additional funds.


The drug "L-thyroxine" it is forbidden to use his intolerance. The drug is prescribed with caution, if identified:

  • severe hypofunction of the thyroid gland, present in a patient for a long time;
  • thyrotoxicosis;
  • malabsorption syndrome
  • failure of the pituitary gland or the adrenal cortex
  • diabetes (diabetes, diabetes insipidus)
  • diseases of the cardiovascular system.

When treating pregnant women are excluded first pituitary and hypothalamic hypothyroidism and then assigned to "L-thyroxine". The doctors indicate that this drug impairs the action of oral medications that reduce the amount of insulin and sugar, enhances the effectiveness of tricyclic antidepressants and anticoagulants.

Some tools, such as "Clofibrate", "Phenytoin", salicylates, "Furosemide" increase the concentration of the drug in the blood. Antithyroid drugs, "Aminoglutethimide", "Metoclopramide", "Somatostatin", "Diazepam", "Lovastatin", "Dopamine", "Carbamazepine", "Levodopa", "chloral Hydrate", beta-blockers, "Amiodarone", "Ethionamide" impact on the pharmacokinetics of funds.

Method of application

Consider the application of the tools "L-thyroxine". Instruction manual, reviews indicate that for the treatment of incipient hypothyroidism, doctors prescribe at 25-100 mcg/day of the drug, while the maintenance dose is 125-250 mg/day. With regard to the treatment of children, it is recommended to take 12.5-50 µg funds for therapy and 100-150 g per 1 m2 of body surface as a maintenance dose. In congenital hypothyroidism children per 1 kg of body weight per day is prescribed:

  • children under 6 months - 8-10 mcg;
  • children 6–12 months old — 6–8 mcg;
  • children aged 1 to 5 years 5-6 mcg
  • children older than 6 years (under 12 years) – 4-5 mcg.

For the treatment of endemic goitre is often prescribed to "L-thyroxine". The reviews contain information about the dosage that is used in this case. Typically used for 50 mcg of funds per day. This dose is gradually adjusted to 100-200 micrograms.

When euthyroid goiter and after surgery, the drug is prescribed as a prophylactic agent. Per day, adults are advised to use 75–200 μg of the drug, and children — 12.5–150 μg.

If additional therapy based on thyrostatic medication is used, treatment is performed using 50-100 μg of the drug per day.

When tested thyroid test is taken 3 mg "L-thyroxine". It is used on an empty stomach or after eating for Breakfast a light meal. During the week prior to study a single receiving means "L-thyroxine". Manual, reviews of patients who have been exposed to operations in connection with enologia, it is recommended each day to apply in 150-300 micrograms.

Pathological changes in the cardiovascular system, require the use of "L-thyroxine" in small doses. The amount used of the drug should gradually increase, given the results of electrocardiographic studies.

The dose of the drug used for long-term therapy in relation to elderly patients is 25 mg, for 6-12 months it is increased to a full dose, which is enough for maintenance therapy.

During pregnancy (trimesters 1st and 2nd) are used in large doses. The dosage is increased to 25 %.

The use of the drug during pregnancy and breastfeeding

During pregnancy and breastfeeding requires a special use tools "L-thyroxine". In pregnancy, the doctors recommended to continue the treatment of hypothyroidism using large doses of the drug. An increased dosage is required due to the high content of thyroxine-binding globulin. The amount of thyroid hormone that enters the breast milk, not enough to harm the child's health.

Pregnant women are forbidden to use "L-thyroxine" together with thyreostatics drugs as a result of taking "L-tyrosine" can be a need to increase the dose of thyreostatics, which have the ability to pass through the placental barrier and induce the development of hypothyroidism in the fetus.

Breastfeeding involves the careful use of the tool and only in those doses that have been recommended by a doctor, under his supervision.

Reception "L-thyroxine" for weight loss

It is possible to use the "L-thyroxine" for weight loss. Reviews confirm that the drug actually has the ability to eliminate excess weight. When you need to get rid of extra pounds, "L-thyroxine" every day is used in a dose of 50 mcg. This quantity of drug is taken for two times, definitely in the first half of the day. In addition, use of β-blockers, the required dose which is determined depending on the pulse frequency.

Starting dose "L-thyroxine" gradually adjusted to 150-300 micrograms. This amount of drug divided into 3 doses, to be implemented no later than 18:00. Must not only increase the dosage means "L-thyroxine". For weight loss (reviews confirm this) is required and the increase in the daily dose of β-blocker. The drug dosage is determined individually. It is assigned correctly, if at rest the heart rate is 60-70 beats per minute If there are pronounced side effects, the dose is reduced.

For weight loss enough of the course, the duration of which corresponds to 4-7 weeks. No need to abruptly abandon the drug, this should be done smoothly. Used means every 14 days consumed in smaller quantities. If this way of losing weight causes diarrhea, to drugs used should be added to "Loperamide". This drug is in capsules, taken every day (1 or 2 drops). "L-thyroxine" treated courses, keeping intervals of at least 3-4 weeks.

Side effects

Consider adverse reactions after taking funds to "L-thyroxine" – side effects. Reviews reflect the absence of side effects in cases when the drug is taken in compliance with all recommendations of the doctor and under its control. For patients sensitive to the action of "L-thyroxine", can develop allergies. In other cases, basically it was the overdose leads to the fact that we are developing for the treatment of tool "L-thyroxine" side effects. Reviews inform that may notice the following effects:

  • arrythmia, stenocardia, arrhythmia, tachycardia, palpitations
  • convulsions, fever, intense weakness, weight loss, hyperthermia, hyperhidrosis
  • disorders of the menstrual cycle;
  • headache, tremor, restlessness, insomnia, brain pseudo-tumors;
  • itching, rash, angioedema
  • vomiting and diarrhea.

At revealing of side effects it is required to reduce the dose of the drug "L-thyroxin". Reviews also report short cessation of treatment in such cases.

There is information about sudden death after a long dose of high doses of the drug, which provoked a violation of the heart.

When side effects fade, the treatment continues. However, in this case a new dose is selected with care. In case of allergic reaction required removal of the drug.

Special instructions

Thyroid hormones, used in small doses, lead to the appearance of an anabolic effect, and in large doses - to the manifestation of a powerful catabolic effect on the metabolism of proteins.

For the correct determination of the optimal dose of medication, patients are first examined, then, on the basis of the obtained indicators, the necessary dosage is selected. For women, the norm of thyroxin is 71-142 nmol / l, for men - 59-135 nmol / l.

After removal of the thyroid gland is usually a decrease in total thyroxine T4. The same result is present after treatment of overactive thyroid, treatment drugs, within which there is radioactive iodine and autoimmune thyroiditis. The norm of this substance is 9-19,1 nmol/l Decrease thyroxine T4 indicates the presence of hypothyroidism and requires treatment.

Analogs reviews

"L-thyroxine" has efficient counterparts, one of which is "Eutirox". Which is better – "Eutirox" or "L-thyroxine"? Reviews show that these drugs are dosed the same and they are appointed for treatment of the same disorders. Means has the same contraindications, and therefore, the effect of "Eutiroks" similarly to "L-thyroxine". Both drugs are effective and therefore no matter what to choose – "Eutirox" or "L-thyroxine". Reviews show that the original can be substituted analogue. To structural analogues, except for the drug "Eutirox" belong to "L-thyroxine 50" and "L-thyroxine 100", "Levothyroxine", "Biothrax".

Feedback about the drug "L-thyroxine" in most cases positive. This tool restores the balance of hormones in the body that significantly improves overall health. Despite the large number of good reviews there are negative. They are mainly related to side effects, which sometimes renders the drug.

It is important to understand that "L-thyroxin" can be treated only after the doctor appointment, and only if there is evidence of reduced function of the thyroid gland. This violation often leads to the recruitment of extra pounds. Regarding the comments about using this tool for weight loss, it can be concluded that the correction used is indeed possible. Especially good effect is observed when combining this method with a low-carb diet. It is not necessary to begin receiving funds to "L-thyroxine" if the thyroid gland functions normally.

Interaction with other medications

Consider the reaction of the body which may be present in the treatment of the original means of "L-thyroxine" or equivalent, for example, "L-thyroxine 100". Reviews show that the simultaneous administration of these drugs with antidiabetic remedies treatment becomes less effective.

If you want to perform a complex treatment, it requires regular checks of blood clotting. When poor performance reduce the dosage of anticoagulants.

The drug is not recommended to be taken simultaneously with protease inhibitors, since in this case its action may be weak.

"Cholestyramine and Colestipol" impair absorption "of L-thyroxine and similar means, for example, the drug "L-thyroxine 50". The reviews contain information about the necessity of medication no later than 4-5 hours before taking "Cholestyramine" and "Colestipol".

Preparations based on iron, calcium carbonate and aluminum worsen the effect of “L-thyroxin”, therefore the drug is taken not later than 2 hours before their use.

When you assign other drugs the physician should consider not only individual characteristics of the patient, but also their interaction with the "L-thyroxin". Then the risk of adverse action will be minimal, and efficiency "L-thyroxine" maximum.