Levothyroxine Sodium Tablets

Pharmacology: The synthetic levothyroxine contained in this product is identical to the thyroxine naturally secreted by the thyroid gland. Like endogenous hormones, it is converted to T3 in peripheral organs and then exerts its specific effects by binding to T3 receptors. The human body cannot distinguish between endogenous and exogenous levothyroxine. Toxicology: Levothyroxine has very mild acute toxicity. Chronic toxicity studies in animals of different species (rats, dogs) have found that when rats are given high doses of levothyroxine sodium, signs of liver disease, an increased incidence of spontaneous nephropathy, and changes in organ weights occur. Only very small amounts of ineffective thyroid hormones cross the placenta. Sufficient human test data have shown that the use of levothyroxine at different stages of pregnancy has no toxic effects on the fetus and does not cause malformations. There are no reports that this product impairs male or female fertility, nor is there any evidence that fertility impairment is related to this product. There is no information on the mutagenicity of this product. So far, there is no evidence that thyroid hormones can cause genomic changes that harm the offspring. No long-term animal studies have been conducted on the carcinogenicity of levothyroxine.

Levothyroxine sodium. Its chemical name is: O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine monosodium salt. Chemical name: O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine monosodium salt Molecular weight: C15H25I4NNaO4·xH2O

This product is white or off-white tablets.

It is suitable for long-term replacement treatment of congenital hypothyroidism (cretinism) and hypothyroidism caused by various reasons in children and adults. It can also be used for suppression (and replacement) treatment of simple goiter, chronic lymphocytic thyroiditis, and thyroid cancer surgery. It can also be used for suppression tests to diagnose hyperthyroidism.

The doses recommended in this item are general principles, and the individual daily dose of the patient should be determined based on the results of laboratory and clinical examinations. Because T4 and fT4 levels are elevated in many patients, the basal concentration of thyroid-stimulating hormone in serum is a reliable basis for determining treatment methods. Except for rapid dose increases, which are very important for newborns, general thyroid hormone treatment should start with a low dose and gradually increase the dose every 2-4 weeks until a sufficient dose is reached. For elderly patients, patients with coronary heart disease, and patients with severe or long-term hypothyroidism, special attention should be paid to the initial stage of thyroid hormone treatment. A lower initial dose (e.g., 12.5 μg/day) should be selected and the dose increased slowly over a longer time interval (e.g., 12.5 μg/day every two weeks). In addition, the value

If the drug is taken as directed and clinical and laboratory indicators are monitored, adverse reactions generally do not occur. If the individual's tolerance dose is exceeded or the drug is overdosed, especially due to a rapid increase in the dose at the beginning of treatment, the following clinical symptoms of hyperthyroidism may occur, including: tachycardia, palpitations, arrhythmia, angina, headache, muscle weakness and cramps, flushing, fever, vomiting, menstrual disorders, pseudotumor cerebri, tremor, restlessness, insomnia, sweating, weight loss and diarrhea. In the above cases, the patient's daily dose should be reduced or the drug should be discontinued for a few days. Once the above symptoms disappear, the patient should carefully restart the drug treatment. Allergic reactions may occur in some hypersensitive patients.

It is contraindicated for patients with non-hypothyroid heart failure, tachyarrhythmias, recent myocardial infarction, and those who are allergic to the drug.

Precautions for children: Please refer to "Dosage and Administration". Precautions for pregnancy and lactation: Special attention should be paid to continued use of thyroid hormone treatment during pregnancy and lactation. The dose of this product may increase during pregnancy. So far, despite the widespread use of this product by pregnant women, there has been no report indicating that this product will cause harm to the fetus. Even in the case of high-dose levothyroxine treatment, the amount of thyroid hormone exuded into breast milk during breastfeeding is not enough to cause hyperthyroidism or suppression of TSH secretion in the infant. Levothyroxine should not be used in combination with antithyroid drugs to treat hyperthyroidism during pregnancy because the addition of levothyroxine increases the dose of antithyroid drugs. Unlike levothyroxine, effective doses of antithyroid drugs can cross the placenta, so combined levothyroxine treatment requires higher doses of antithyroid drugs, which may cause hyperthyroidism in the elderly. Precautions for the elderly: Please refer to "Dosage and Administration".

Antidiabetic drugs: Levothyroxine may reduce the hypoglycemic effect of this type of drug. Therefore, when starting thyroid hormone treatment, the patient's blood sugar level should be monitored frequently, and the dose of antidiabetic drugs should be adjusted if necessary. Coumarin derivatives: Levothyroxine can replace the binding of anticoagulants to plasma proteins, thereby enhancing their effects. Therefore, when starting thyroxine treatment, coagulation indicators should be monitored regularly and the dose of anticoagulants should be adjusted if necessary. Cholestyramine, colestipol: Cholestyramine will inhibit the absorption of levothyroxine sodium, so levothyroxine sodium should be taken 4-5 hours before taking cholestyramine. The situation of colestipol is the same as that of cholestyramine. Aluminum-containing drugs, iron-containing drugs and calcium carbonate: Relevant literature reports that aluminum-containing drugs (antacids, ulcerogen) may reduce the effect of levothyroxine. Therefore

Keep away from light and store in a sealed container below 25℃.

100 micrograms (as levothyroxine sodium)

24 months