Levothroid - official instructions for use
Trade name of the drug:
L-Thyroxine 100 Berlin-Chemie
International non-proprietary name:
Active ingredient: levothyroxine sodium - 0.100 mg.
Excipients: calcium hydrophosphate dihydrate - 31.90 mg, microcrystalline cellulose 32.00 mg, sodium carboxymethyl starch (type A) - 24.00 mg, dextrin - 13.60 mg, 2.40 mg long-chain.
Description: round, slightly convex tablets of white or white color with a slightly yellowish tinge, with a risk on one side and an embossed “100” on the other.
Pharmacological group: Thyroid agent.
ATX Code: H03AA01
Synthetic levorotatory isomer of thyroxine. After partial transformation into triiodothyronine (in the liver and kidneys) and transition into the cells of the body, it influences 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 tissue oxygen demand, stimulates the metabolism of proteins, fats and carbohydrates, and increases the functional activity of the cardiovascular system and the central nervous system.
In large doses, inhibits the production of thyrotropin-releasing hormone 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 is preserved after drug withdrawal. The clinical effect in hypothyroidism appears after 3-5 days. Diffuse goiter decreases or disappears within 3-6 months.
When ingested, levothyroxine sodium is absorbed almost exclusively in the upper small intestine. Absorbed up to 80% of the dose of the drug.
Eating reduces the absorption of levothyroxine sodium. The maximum concentration in serum is reached approximately 5-6 hours after ingestion. After absorption, more than 99% of the drug binds to serum proteins (thyroxin-binding globulin, thyroxin-binding prealbumin and albumin). In various tissues, about 80% of levothyroxine sodium is mono-deiodination with the formation of 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.
Indications for use
- euthyroid goiter;
- as a replacement therapy and for the prevention of relapse of goiter after resection of the thyroid gland;
- thyroid cancer (after surgical treatment);
- diffuse toxic goiter: after reaching the euthyroid state with antithyroid drugs (in the form of a combination or monotherapy);
- as a diagnostic tool when conducting a test of thyroid suppression.
- hypersensitivity to the active substance or to any of the excipients that make up the preparation (see the Composition section);
- untreated thyrotoxicosis;
- acute myocardial infarction, acute myocarditis;
- Untreated adrenal insufficiency.
The drug should be prescribed with caution in diseases of the cardiovascular system: ischemic heart disease (atherosclerosis, angina, myocardial infarction), arterial hypertension, arrhythmia, diabetes mellitus, severe long-term hypothyroidism, malabsorption syndrome (may require dose adjustment).
Use during 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 content of thyroxin-binding globulin. The amount of thyroid hormone secreted in breast milk during lactation (even during treatment with high doses of the drug) is not enough to cause any disorders 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 penetrate the placenta, hypothyroidism can develop in the fetus. During breastfeeding, the drug should be taken with caution, strictly in recommended doses under the supervision of a physician.
Dosage and administration
The daily dose is determined individually depending on the evidence.
Levothroid in a daily dose is taken orally in the morning on an empty stomach, or at least 30 minutes before a meal, drinking a pill with a small amount of liquid (half a glass of water) and not chewing.
When performing replacement therapy for hypothyroidism (in the absence of cardiovascular diseases), Levothroid is prescribed in a daily dose of 1.6-1.8 µg / kg body weight. With significant obesity, 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 - 50-100 mcg / day, men - 50-150 mcg / day.
Patients with cardiovascular disease or over 55 years old.
Initial dose - 25 mcg per day. Increase by 25 mcg with an interval of 3-6 weeks until the normalization of TSH in the blood. If symptoms occur from the cardiovascular system, correct the treatment of cardiovascular diseases.
Infants and children up to 3 years of age receive a daily dose of Levothroid at one time 30 minutes before the first feed. 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 of 25 µg / day, the dose is increased to maintenance at longer intervals of 25 µg / day every 2 weeks and more often determine the concentration of TSH in the blood. In hypothyroidism, Levothroid is usually taken for a lifetime. In thyrotoxicosis, Levothroid is used in complex therapy with antithyroid drugs after reaching the euthyroid state. In all cases, the duration of drug treatment is determined by the doctor.
Recommended doses of thyroxine for the treatment of congenital hypothyroidism
Age - Daily dose (mcg) - Dose of thyroxine per body weight (mcg / kg)
0-6 - months 25-50 - 10-15
6-24 - months 50-75 - 8-10
from 2 to 10 years - 75-125 - 4-6
from 10 to 16 years - 100-200 - 3-4
> 16 years old - 100-200 - 2-3
Indications - Recommended doses (Levothroid, mcg / day)
Treatment of euthyroid goiter - 50-200
Prevention of relapse after surgical treatment of euthyroid goiter - 50-200
In the treatment of thyrotoxicosis - 50-100
Suppressive therapy for thyroid cancer - 150-300
Test thyroid suppression 4 weeks before the test Z weeks before the test 2 weeks before the test 1 week before the test
Levothroid 50 mcg / day 100 mcg / day 150-200 mcg / day 150-200 mcg / day
For accurate dosing of the drug, use the most appropriate form of release of the drug L-thyroxine (50, 75, 100, 125 or 150 μg).
With proper use under the supervision of a physician, no side effects are observed.
In case of hypersensitivity to the drug, allergic reactions may occur.
With an overdose of the drug, symptoms characteristic of thyrotoxicosis are observed: tachycardia, heart rhythm disturbance, heart pain, anxiety, tremor, insomnia, hyperhidrosis, loss of appetite, weight loss, diarrhea, vomiting, headache, increased fatigue, muscle spasm. Depending on the severity of symptoms, the doctor may recommend a decrease 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 begin with caution with a lower dose. Antithyroid drugs are not recommended.
Interaction with other drugs
Levothyroxine sodium enhances the effect of indirect anticoagulants, which may require lowering their dose.
The use of tricyclic antidepressants with levothyroxine sodium can lead to an increased effect of antidepressants.
Thyroid hormones can increase the need for insulin and oral hypoglycemic drugs. More frequent monitoring of blood glucose concentration 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 action of cardiac glycosides. With simultaneous use of colestyramine, colestipol and aluminum hydroxide, they decrease 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 is possible at the level of protein binding.
With simultaneous use with phenytoin, salicylates, clofibrate, furosemide in high doses, the content of levothyroxine sodium and T4 not bound to plasma proteins increases.
Somatotropin when used simultaneously with levothyroxine sodium can accelerate the closure of the epiphyseal growth zones.
Consumption of phenobarbital, carbamazepine and rifampicin may increase the clearance of levothyroxine sodium and require an increase in dose.
Estrogens increase the concentration associated with thyroglobulin fraction, which may lead to a decrease in the effectiveness of the drug.
Amiodarone, aminoglutetimid, para-aminosalicylic acid (PAS), ethionamide, antithyroid drugs, beta-adrenoblockers, chloral hydrate, diazepam, levodopa, dopamine, metoclopramide, lovastatin, somatostatin, influence synthesis, stimulation, dopamine, dopamine, metoclopramide, lovastatin, somatostatin, influence synthesis, stimulation, synthesis, dopamine, metoclopramide, lovastatin, somatostatin.
Products containing soy may reduce the absorption of levothyroxine sodium (dose adjustment may be necessary).
In hypothyroidism, caused by damage to the pituitary gland, it is necessary to find out whether there is at the same time adrenal insufficiency. In this case, replacement therapy with glucocorticosteroids should begin before the treatment of hypothyroidism with thyroid hormones in order to avoid the development of acute adrenal insufficiency.
The effect of the drug on the ability to drive vehicles and control mechanisms
Levothroid does not affect the ability to drive vehicles and work requiring increased concentration.
Tablets 100 mcg. 25 tablets in a blister pack [blister] [PVC / PVDC / aluminum foil or aluminum foil / aluminum foil]. On 1, 2 or 4 blisters together with the instruction for application are placed in a cardboard pack.
Store at a temperature not higher than 25 ° С. Keep the medicine out of the reach of children!
2 years. Do not use after the expiration date printed on the package!
Pharmacy sales terms
The thyroid gland is located on the front surface of the neck. Most people can see or feel it. The thyroid gland has two lobes, connected by a narrow isthmus. This gland absorbs iodine from food and blood and produces a hormone that performs various functions. The thyroid gland contains mainly two types of cells:
- Follicular cells that produce and maintain thyroid hormone. In addition, they produce a special protein called thyroglobulin and
- Cells that produce another hormone - calcitonin.
From these cells, various types of cancer arise, differing in course, treatment and outcome.
Various tumors appear in the thyroid gland, most of them (about 95%) are benign. Due to the fact that the thyroid gland is located close to the skin, the tumor that has arisen in it has the appearance of a node in the neck. Nodes in the gland can appear at any age, more often detected in adults, who themselves detect a tumor.
Malignant tumors of the thyroid gland
Only 5-10% of thyroid tumors are malignant. There are several types of thyroid cancer:
Papillary carcinoma accounts for 80-85% of the total number of malignant tumors of the thyroid gland. A tumor grows very slowly and occurs, as a rule, in one lobe of the gland, but in 10-20% of patients the lesion is bilateral. Although this tumor grows slowly, it often affects the cervical lymph nodes. Fortunately, most people with thyroid papillary cancer recover.
Follicular carcinoma is the second most common malignant tumor of the thyroid gland and is 5-10% of the number of all tumors of the gland. It is more often detected in countries where there is a shortage of iodine in food. Usually this type of cancer does not extend beyond the thyroid gland, but can sometimes metastasize to the lungs and bones. Unlike papillary carcinomas, follicular carcinomas less commonly involve lymph nodes in the process. The prognosis in patients with follicular carcinoma is the same or slightly worse than in patients with papillary carcinoma.
Anaplastic carcinoma is a rare type of malignant tumor of the thyroid gland. The tumor quickly affects the structures of the neck and spreads throughout the body, most often leading to death.
Medullary carcinoma of the thyroid gland is the only tumor arising from C-cells and accounts for 5% of the total number of malignant tumors of the gland. May affect the lymph nodes, lungs and liver before the primary lesion is detected. This tumor produces the hormone calcitonin and cancer embryonic antigen, which can be detected in the patient's blood.
Thyroid lymphoma develops from lymphocytes - cells of the immune system, but is very rare.
How often does thyroid cancer occur?
In 2002, 8,258 cases of thyroid cancer were detected in Russia, of which 86% of tumors were diagnosed in women. At the age of 30 - 39 years, women fall ill 7 times more often than men. The maximum incidence of thyroid cancer occurs between the ages of 50-59 years. Over the 10-year period from 1993 to 2002, an increase in the incidence of thyroid cancer was noted. High rates of morbidity in the male population were found in the Bryansk, Oryol, Saratov regions, the Altai Territory, the Krasnodar Territory. The Altai Territory, Bryansk Region, Krasnodar Territory, and Sakhalin Region lead in terms of the incidence of women.
It is estimated that in 2004 in the United States 23,600 new cases of thyroid cancer will be diagnosed. Of these, 17640 cases will be detected in women and 5960 - in men. 840 women and 620 men (a total of 1,460 patients) may die of thyroid cancer in 2004. The number of new cases of thyroid cancer is growing and amounts to 3% per year per 100,000 population.
What causes thyroid cancer?
Great progress has been made in understanding how changes in human DNA can turn normal thyroid cells into malignant cells. DNA is a molecule that carries information about the activities of all cells in the body. We are usually similar to our parents, as they are the sources of our DNA. However, DNA does not only affect our appearance. It also determines the risk of developing certain diseases, including cancer.
Some genes (parts of DNA) control the growth and division of cells. Genes that promote cell division are called oncogenes. Other genes slow down cell division or cause their death, and they are called tumor-suppressing genes. Neoplasms can occur as a result of mutations (changes) of genes and their effects on oncogenes and tumor-suppressing genes.
People can inherit damaged DNA from a parent. In many cases, human DNA is damaged as a result of exposure to environmental factors, such as smoking or radiation. Sometimes DNA mutations occur for unknown reasons.
DNA mutations causing some forms of papillary thyroid cancer involve certain parts of the RET oncogene. These mutations are acquired during life and are less likely to be inherited. They are present only in tumor cells and are not transmitted to the children of the patient. Acquired changes in other oncogenes and tumor suppressor genes (for example, ras, trk, gsp, p53) also play a role in the occurrence of papillary and follicular thyroid cancer.
Mutations in patients with medullary thyroid carcinoma involve other parts of the RET gene (compared with papillary carcinoma). Almost all patients with an inherited form of medullary thyroid cancer in 1 of 5 cases of sporadic forms of the same cancer have a mutation in the RET gene. Most patients with sporadic medullary thyroid cancer have acquired mutations that are present only in their tumor cells. Patients with familial medullary cancer inherit a mutation of the RET gene from the parent. These mutations are present in every cell of the body and can be detected by examining the DNA of blood cells.
Risk factors for thyroid cancer
A risk factor is what increases the likelihood of developing cancer. For example, the intense exposure of the sun to the skin is a risk factor for skin cancer. Smoking is a risk factor for tumors of the lungs, mouth, larynx, bladder, kidneys and some other organs. However, the presence of one or several risk factors does not mean that a person will definitely develop cancer.
To date, there are several factors that increase the likelihood of thyroid cancer. However, most patients with thyroid cancer have no obvious risk factors. In addition, many people with one or more risk factors do not develop thyroid cancer at all. If a person has one or more risk factors, it is impossible to conclude how a certain factor affects the occurrence of cancer.
Low iodine content in food
Papillary and follicular thyroid cancer is more common in areas of the world where there is a low iodine content in foods. In some countries, iodine is specifically added to food salt and other foods.
A proven risk factor for papillary thyroid cancer is irradiation of the head and neck in childhood. In the past, children were exposed to acne, a fungal infection of the scalp, an enlarged thymus gland and to reduce the size of the tonsils or adenoids. After a few years, this type of treatment was associated with an increased risk of developing thyroid cancer. Radiation exposure in adults is accompanied by a slight risk of developing thyroid cancer.
A number of studies have shown that the increased risk of nodules in the thyroid gland and even cancer is associated with radioactive fallout during the testing of nuclear weapons or incidents at nuclear power plants. Thus, there has been an increase in cases of thyroid cancer among children near the Ukrainian city of Chernobyl, where in 1986 there was an explosion at a nuclear power plant. At the same time, millions of people were exposed to radioactive fallout. Rescuers and people living near the scene of the incident also have an increased incidence of thyroid cancer, although they were already adults at the time of the accident.
People with certain hereditary diseases also have an increased risk of developing thyroid cancer. Thus, Gardner syndrome and familial polyposis are associated with an increased risk of thyroid cancer. Cowden’s rare genetic disorder is also associated with an increased risk of thyroid cancer.
20% of medullary thyroid cancer is the result of an inherited, altered gene — family medullary carcinoma of the thyroid gland.
Gender and age
Benign thyroid nodules occur more frequently in women than in men. Most cases of papillary and follicular cancer are detected at the age of 30-50 years. Benign and malignant tumors of the thyroid gland can occur in people of all ages.
Lifestyle risk factors
Tobacco and alcohol are the main risk factors for most head and neck tumors, including tumors of the mouth, pharynx, and esophagus. On the other hand, it is not proven that these factors increase the risk of developing thyroid cancer.
Is it possible to prevent the occurrence of thyroid cancer?
The risk factors are not known in the majority of patients with thyroid cancer, therefore it is impossible to prevent the development of such a disease in the vast majority of people. Some researchers believe that the increase in thyroid cancer can be explained by X-ray examinations of young children. This assumption has not been confirmed, however, if possible, x-rays should be avoided in children.
Most familial cases of medullary thyroid cancer can be prevented by conducting genetic blood tests. If such a disease is detected in the family, the rest of the family members should be examined.
If there are cases of medullary thyroid cancer in the family, the rest of the family should be seen by a doctor who has the latest genetic counseling and testing information.
If RET gene mutations have been identified associated with familial medullary thyroid cancer (even if there are no obvious nodules in the gland and other symptoms of the disease), then an operation can be offered to prevent the occurrence of medullary thyroid cancer. The only way to prevent medullary thyroid cancer in the presence of RET gene mutations is to remove the entire gland. After surgery, it is necessary to carry out hormone replacement therapy.
Is early detection of thyroid cancer possible?
In many cases, thyroid cancer can be detected early. In fact, in most patients, cancer of this location is diagnosed in earlier stages, and therefore is treated more effectively. In rare cases, thyroid cancer is not accompanied by symptoms and therefore is detected in the later stages. Thyroid tumors are diagnosed early if the patient visits a doctor immediately after he has noticed it. Many tumors are detected during regular check-ups.
If there are unusual symptoms in the form of a tumor nodule on the neck or neck swelling, you should immediately see a doctor. Some researchers recommend that the neck be self-examined twice a year to detect unusual formations or tumor nodes.
People with a family of cases of medullary thyroid cancer have a very high risk of developing this type of cancer. Removal of the thyroid gland in children in such families is an effective method of preventing this type of cancer, which can be fatal. If a patient refuses a genetic examination or operation to prevent medullary thyroid cancer, then there are other methods that can help identify the cancer at an early stage and provide effective treatment.
Diagnosis of Thyroid Cancer
Signs and symptoms of thyroid cancer
Increased attention to signs and symptoms is the best way to early diagnose most thyroid cancers. With this type of cancer, the following signs and symptoms may appear:
- Compaction (tumor formation) on the neck, and sometimes fast-growing.
- Pain in the neck, sometimes extending to the ear.
- Disturbance of swallowing.
- Labored breathing.
- Cough not associated with an infectious disease.
If any of these signs or symptoms appear, you should immediately consult a doctor. Other tumors of the neck and many non-neoplastic diseases can cause some of the above symptoms. However, the only way to find out if these symptoms are related to thyroid cancer is through a medical examination. The sooner the correct diagnosis is established, the faster the treatment will be initiated and the more effective it may be.
Disease data and survey
If there are signs or symptoms suspicious for thyroid cancer, then a full medical examination is necessary. The doctor will ask about risk factors, symptoms and other health problems. If anyone in the family had thyroid cancer, especially medullary cancer, or pheochromocytoma - an adrenal tumor, you must inform your doctor.
During the examination, the doctor will receive additional information about the signs and symptoms of thyroid cancer and health status. The doctor will pay special attention to the size and consistency of the thyroid gland and enlarged lymph nodes in the neck and will prescribe an additional examination.
Thyroid scan: During this study, a small amount of radioactive iodine or technetium is injected through the mouth or into a vein. The injected radioactive substance accumulates in the thyroid gland and the amount of accumulated substance is estimated by a special camera. The altered areas of the thyroid gland accumulate a smaller amount of radioactive substance in comparison with the surrounding tissues and are called "cold" nodes. Nodes that accumulate more radioactive substances are called "hot".
Most of the thyroid gland nodes look like “cold” on scans. Given the fact that both benign and malignant nodes may have cold foci, this study does little to help diagnose thyroid cancer. It is performed when the results of a fine needle biopsy are questionable. If the biopsy confirms thyroid cancer, then the scan helps to clarify the extent of the spread of the tumor process (stage).
After the thyroid gland is removed, the gland is re-scanned. Scanning with radioactive iodine is often used in patients with papillary and follicular thyroid cancer. Such a scan is not used for medullary thyroid cancer, since the cells of this type of cancer do not accumulate iodine. Scanning the thyroid gland with radioactive iodine gives the most accurate results in patients with a high level of thyroid stimulating hormone (thyrotropin).
Ultrasound: The number and size of thyroid nodules is studied using this method. However, with ultrasound thyroid cancer and benign tumors look the same, so this method is often not used.
Computed tomography (CT): This method is not commonly used to diagnose thyroid cancer, but is used to clarify the stage of the disease.
Magnetic resonance imaging (MRI): The method is very useful when examining cancer patients, as in some cases it allows to distinguish a benign tumor from a malignant one.
Blood test. A blood test cannot be diagnosed with thyroid cancer. However, the determination of thyroid stimulating hormone in the blood makes it possible to judge the general state of the thyroid gland. If you suspect medullary thyroid cancer, it is necessary to investigate the levels of calcitonin in the blood. This study may help diagnose medullary thyroid cancer.
Thyroglobulin is a protein produced by the thyroid gland. However, after removing most of the gland or destroying it with radioactive iodine, thyroglobulin levels should be very low. If this does not happen, then the cancer cells are still present. With increasing levels of this protein, you can think about the recurrence of the tumor.
Thyroid Cancer Treatment
After the discovery of thyroid cancer, a treatment program is discussed. This takes into account both the type of tumor, and the stage and the general condition of the patient.
Treatments for thyroid cancer include surgery, radioactive iodine treatment, hormone therapy, external radiation, and chemotherapy. It is better to use two or more methods that can cure most of the patients with thyroid cancer.
If a cure is impossible for some reason, then it is necessary to remove or destroy as much tumor tissue as possible and prevent the growth, spread or relapse of cancer for a long period of time. Sometimes, only symptomatic treatment is performed to reduce the severity of symptoms, such as pain, breathing problems or swallowing.