Levothyroxine sodium* (Levothyroxine sodium*)
ATH
H03AA01 Levothyroxine sodium
Pharmacological group
- Synthetic thyroid hormone [Thyroid hormones, analogues and antagonists (including antithyroid drugs)]
Composition and form of release
L-thyroxine 50 Berlin-Chemie
Tablets | 1 table |
levothyroxine sodium | 50 mcg |
excipients: calcium hydrogen phosphate, water; MCC; carboxymethyl starch sodium salt (type A); dextrin; long chain partial glycerides |
in a blister 25 pcs.; in a pack of cardboard 2 or 4 blisters.
L-Thyroxine 100 Berlin-Chemie
Tablets | 1 table |
levothyroxine sodium | 100 mcg |
excipients: calcium hydrogen phosphate, water; MCC; carboxymethyl starch sodium salt (type A); dextrin; long chain partial glycerides |
in a blister 25 pcs.; in a pack of cardboard 2 or 4 blisters.
Description of the dosage form
L-Thyroxine 50 Berlin-Chemie: light blue tablets, flat on both sides, with a beveled edge and one-sided notch for division.
L-Thyroxine 100 Berlin-Chemie: yellow to greenish-yellow tablets, flat on both sides, with a bevelled edge, provided with a one-sided notch for division.
Characteristic
Synthetic levorotatory isomer of thyroxine.
pharmachologic effect
Pharmacological effect – thyroid, replenishing the deficiency of thyroid hormones.
After partial transformation into liothyronine (in the liver and kidneys) and transition 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.
Pharmacodynamics
The therapeutic result is observed after 7-12 days, during the same time the effect is maintained after discontinuation of the drug. The clinical result in hypothyroidism is expressed in 3–5 days. Diffuse goiter decreases or disappears within 3–6 months.
Pharmacokinetics
When administered orally, levothyroxine is absorbed almost exclusively in the upper small intestine. Up to 80% of the accepted dosage of the drug is absorbed. Eating reduces the absorption of levothyroxine. Cmax in blood serum is reached 6 hours after ingestion. After absorption, more than 99% of the drug binds to serum proteins. In various tissues, monodeiodination of levothyroxine occurs with the formation of triiodothyronine and inactive products. Thyroid hormones are metabolized primarily 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 in the urine and bile. T1 / 2 – 6-8 days.
Indications for L-Thyroxine 100 Berlin-Chemie
Hypothyroidism (hypofunction of the thyroid gland) of any origin: primary and secondary hypothyroidism, after surgery for struma, as an effect of radioactive iodine therapy (in the role of replacement therapy).
Prevention of recurrence (re-formation) of nodular goiter after goiter surgery with proper thyroid function.
Diffuse goiter with regular function.
As part of combination therapy in the treatment of hyperfunction of the thyroid gland with thyreostatics after achieving its correct function.
Malignant tumor of the thyroid gland, mainly after surgery to suppress tumor recurrence and as replacement therapy.
Contraindications
Increased individual sensitivity to the drug, acute myocardial infarction, untreated adrenal insufficiency, hyperthyroidism.
With caution: in diseases of the cardiovascular system – coronary artery disease (atherosclerosis, angina pectoris, history of myocardial infarction), arterial hypertension, arrhythmias; with diabetes; severe long-term hypothyroidism; malabsorption syndrome (possible dosage adjustment).
Use during pregnancy and lactation
During pregnancy and breastfeeding, treatment should be continued. The use of drugs during pregnancy in combination with thyreostatics is contraindicated. Since thyreostatics, unlike levothyroxine, can cross the placenta, the fetus may develop hypothyroidism.
Side effects
Allergic reactions (skin rash, skin itching). When used in excessively high doses – hyperthyroidism (change in appetite, dysmenorrhea, chest pain, diarrhea, tachycardia, arrhythmia, fever, tremor, headache, irritability, muscle cramps in the lower extremities, nervousness, sweating, difficulty falling asleep, vomiting, weight loss bodies). When used in insufficiently effective doses – hypothyroidism (dysmenorrhea, constipation, dryness, puffiness of the skin, headache, lethargy, myalgia, drowsiness, weakness, apathy, weight gain).
Interaction
Levothyroxine enhances the effect of indirect anticoagulants (probably reducing their dosage). With simultaneous use of cholestyramine lowers the plasma concentration of levothyroxine by inhibiting its absorption in the intestine. Rapid intravenous administration of phenytoin increases the content of levothyroxine and liothyronine not bound to plasma proteins. Salicylates, dicoumarol, furosemide in high doses (250 mg) enhance the effect of levothyroxine, because. capable of displacing it from its binding sites with plasma proteins.
Dosage and administration
Inside, before meals, at least 30 minutes before breakfast. The daily dose of the drug is set and controlled individually based on laboratory and clinical examination data.
As experience shows, with a small body weight and in the presence of a large nodular struma, a low dosage is sufficient.
Unless otherwise prescribed, the following dosage recommendations apply:
with hypofunction of the thyroid gland, the initial daily dosage, for adults – 25-100 mcg, then the dose is increased as prescribed by the doctor every 2-4 weeks by 25-50 mcg until a maintenance daily dosage is reached – 125-250 mcg; children – 12.5–50 mcg, with a long course of treatment, the dosage is determined by the body weight and height of the child (based on an approximate calculation of 100 to 150 mcg of levothyroxine sodium per 1 m2 of body surface);
for the prevention of recurrence of goiter and with diffuse goiter in adults – 75–200 mcg / day;
as part of combination therapy in the treatment of hyperthyroidism with thyreostatics – 50-100 mcg / day;
in the treatment of a malignant tumor, the daily dosage is 150–300 mcg.
Approximate maintenance daily dosage of levothyroxine sodium
Age | Dosage for goiter, mcg / kg / day | Dosage for hypothyroidism, mcg / kg / day |
newborns | 12,5 | 4 |
Infants, 1/4 years | 25–37,5 | 25 |
Infants, 1/2 years | 25–37,5 | 37,5 |
Toddlers, 1 year old | 25–37,5 | 37,5 |
Toddlers, 5 years old | 25–62,5 | 50 |
School children, 7 years old | 50–100 | 75–100 |
School children, 12 years old | 100–150 | 100 |
adults | 75–200 | 125–250 |
The daily dosage of the drug is set individually depending on the indications.
During pregnancy, the need for thyroid hormones increases, so you need to inform the doctor about the pregnancy existing or occurring during the course of treatment so that, if necessary, it is possible to adjust the dosage of the drug.
Overdose
Symptoms: thyrotoxic crisis, sometimes delayed for several days after ingestion.
Treatment: appointment of beta-blockers, intravenous administration of corticosteroids, plasmapheresis.
special instructions
If you need to prescribe other drugs containing iodine, you need to consult a doctor. It is proposed to periodically determine the content of TSH in the blood, an increased level of which indicates an insufficient dosage. The adequacy of thyroid suppressive therapy is also assessed by the suppression of radioactive iodine uptake. With a long-term multinodular goiter, a stimulation test with thyrotropin-releasing hormone should be performed before starting treatment. In most cases of hypothyroidism, the metabolic status should be restored gradually, especially in elderly patients and patients with pathology of the cardiovascular system. For elderly patients, the initial dosage should not exceed 50 micrograms. When used in the II and III trimesters of pregnancy, the dose is often increased by 25%.
Prescribed with caution in severe long-term hypothyroidism. Before starting treatment, the ability of pituitary or hypothalamic hypothyroidism should be excluded.
Manufacturer
Berlin-Chemie AG/Menarini Group, Germany.
Storage conditions of the drug L-Thyroxine 100 Berlin-Chemie
At a temperature of 15–25 °C.
Keep out of the reach of children.