Left thyroxine

General characteristics. Structure:

Active agent: left thyroxine of sodium of 100 mkg; 50 mg; 25 mg.

Pharmacological properties:

Drug of hormones of a thyroid gland. Synthetic left-handed isomer of thyroxine. In small doses possesses anabolic action. Stimulates growth and development in average doses, increases the need of fabrics for oxygen, stimulates metabolism of proteins, fats and carbohydrates, stimulates activity of cardiovascular system and TsNS. In high doses oppresses development of TTRG of a hypothalamus and TTG of a hypophysis.

Pharmacokinetics. After intake it is absorbed from a GIT, absorption makes 48-79%. Reception on an empty stomach increases absorption of active agent. Cmax in plasma is reached approximately in 6 h. Linkng with proteins of plasma (thyroxine - the connecting globulin, thyroxine - the connecting prealbumin and albumine) - more than 99%. Vd makes 0.5 l/kg. Distribution happens, mainly, in a liver, a brain and muscles.
In various fabrics there is a monodeiodinating about 80% of left thyroxine of sodium to formation of triiodothyronine (T3) and inactive products. A small amount of active agent is exposed to deamination and decarboxylation with formation of tetrayodtirouksusny acid, and also to a konjyugirovaniye with sulfuric and glucuronic acids (in a liver).
T1/2 makes 6-7 days. About 15% are removed by kidneys and with bile in not changed look and in the form of conjugates.

Indications to use:

Primary and secondary hypothyroidism; the mixed craw; complex treatment of a toxic craw and autoimmune thyroidites, euthyroid hyperplasia of a thyroid gland; prevention of a recurrence after operational treatment of nodal and malignant new growths of a thyroid gland; cretinism.
Differential diagnostic test of thyroid suppression.

Route of administration and doses:

Establish individually depending on indications. Apply in a dose 12.5-200 mkg of 1 time/days in 20-30 min. prior to food.
When conducting differential diagnostic test of thyroid suppression - once in a dose of 3 mg or within 2 weeks on 200 mkg of 1 times/days.

Features of use:

With extra care apply at patients with cardiovascular diseases (including an ischemic heart disease, heart failure, arterial hypertension). In such cases left thyroxine of sodium should be applied in a low initial dose, increasing it slowly and with big intervals.
At patients of advanced age and at a long current of a hypothyroidism treatment should be begun gradually.
At replacement thyroid therapy at patients with insufficiency of function of bark of adrenal glands without adequate maintenance therapy corticosteroids, development of acute adrenal crisis is possible.
With care to apply at sugar and not diabetes mellitus.
When conducting differential diagnostic test of thyroid suppression by the patient with a diabetes mellitus it is recommended to increase doses of antidiabetic means.
In some cases thyroid hormones can cause or aggravate the previous myasthenic syndrome.

Side effects:

Hyperthyroidism symptoms: are possible (at use in high doses, including at too bystry increase in a dose at the beginning of a course of treatment) tachycardia, palpitation, arrhythmias, stenocardia attacks, a headache, nervousness, a tremor, sleep disorders, feeling of internal concern, muscular weakness and spasms, loss of body weight, diarrhea, disturbances of a menstrual cycle, vomiting.

Interaction with other medicines:

Left thyroxine of sodium exponentiates effect of indirect anticoagulants (coumarin derivatives), reduces efficiency of peroral hypoglycemic means.

At patients with a hypothyroidism and the accompanying diabetes mellitus at the beginning of replacement therapy by drugs of thyroid hormones increase in need for insulin or peroral hypoglycemic means is possible.

Salicylates, Dicumarinum, furosemide (250 mg), Clofibratum can force out left thyroxine from communication with proteins of plasma.

Sukralfat, aluminum hydroxide, calcium a carbonate reduce absorption of left thyroxine from a GIT.

Colestyraminum reduces sodium left thyroxine absorption from a GIT.

At use of a ritonavir increase in need for left thyroxine is possible.

At use of sertraline of patients with a hypothyroidism reduction of effects of left thyroxine of sodium is possible.

At bystry in introduction of Phenytoinum against the background of reception of left thyroxine of sodium increase in level of free left thyroxine in a blood plasma is possible, at the same time arrhythmias can be observed.

At simultaneous use of chloroquine increase in metabolism of left thyroxine, apparently, owing to induction by chloroquine of microsomal enzymes of a liver is possible. At the patients receiving sodium left thyroxine at use of proguanil or chloroquine increase in concentration of TTG is possible.

Contraindications:

Hyperfunction of a thyroid gland of various genesis, acute myocardial infarction, not treated insufficiency of bark of adrenal glands, hypersensitivity to sodium left thyroxine.

Use at pregnancy and feeding by a breast
At pregnancy and in the period of a lactation left thyroxine of sodium should be applied under observation of the doctor. Use in a combination with thyreostatic means at pregnancy is contraindicated in connection with increase in risk of development of a hypothyroidism in a fruit.

Use for elderly patients
At patients of advanced age and at a long current of a hypothyroidism treatment should be begun gradually.

Overdose:

There are no data.

Storage conditions:

List B. In the dry, protected from light place.

Issue conditions:

According to the recipe

Packaging:

Tablets of 100 mkg; 50 mkg; 25 mkg.: 10, 20, 25, 50 or 125 pieces.