Thyrozole, 5 mg 50 pcs

An antithyroid drug. Disrupts synthesis of thyroid hormones by blocking the enzyme peroxidase involved in thyronine iodination in the thyroid gland to form triiodine and tetraiodothyronine. Therefore, the drug is effective in symptomatic therapy of thyrotoxicosis (except for cases of development of the disease due to release of hormones after destruction of thyroid cells after radioactive iodine treatment or in thyroiditis).

Tyrosol does not affect the process of release of synthesized thyronines from thyroid follicles. This explains the latent period of varying duration, which may precede normalization of plasma T3 and T4 levels, i.e. improvement of the clinical picture.

The drug reduces basal metabolism, accelerates iodide excretion from the thyroid gland, and increases reciprocal activation of pituitary TTH synthesis and secretion, which may be accompanied by some thyroid hyperplasia.

The duration of action of the drug after a single dose is almost 24 hours.

Pharmacokinetics

Absorption

Tiamazole is quickly and almost completely absorbed after oral administration. Cmax in plasma is reached within 0.4-1.2 h.

Distribution

It is practically not bound to plasma proteins. It accumulates in the thyroid gland.

Small amounts of thiamazole are found in breast milk.

Metabolism

It is slowly metabolized in the thyroid gland as well as in the kidneys and liver.

Elimination

The T1/2 is about 3-6 hours. Thiamazole is excreted in the urine (within 24 hours 70% of the drug, with 7-12% unchanged) and in the bile.

Pharmacokinetics in special clinical cases

The T1/2 is increased in patients with hepatic insufficiency.

The pharmacokinetic parameters of the drug are independent of the functional state of the thyroid gland.

Indications

Hyperthyroidism

• Preparing for surgical treatment of thyrotoxicosis;
• preparing for the treatment of thyrotoxicosis with radioactive iodine;therapy during the latent period of radioactive iodine action (conducted prior to the onset of radioactive iodine – for 4-6 months);
• prevent thyrotoxicosis when prescribing iodine products (including cases of iodine-containing radiopaque contrast agents), in the presence of latent thyrotoxicosis, autonomous adenomas or thyrotoxicosis in the anamnesis.

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Active ingredient

Thiamazole

Composition

1 tablet cathiamazole 5 mg

Supplementary substances:

colloidal silicon dioxide – 2 mg,

sodium carboxymethyl starch – 2 mg,

magnesium stearate – 2 mg,

Hypromellose 2910/15 – 3 mg,

talc – 6 mg,

cellulose powder – 10 mg,

Corn starch – 20 mg,

lactose monohydrate – 200 mg.

Composition of the film coating:

iron oxide yellow dye – 0.04 mg, dimethicone 100 – 0.16 mg, macrogol 400 – 0.79 mg, titanium dioxide – 1.43 mg, hypromellose 2910/15 – 3.21 mg.

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How to take, the dosage

The drug is taken orally after a meal. The tablets should be taken without chewing and with plenty of liquid.

The daily dose is given as a single dose or divided into 2-3 single doses. At the start of treatment, single doses are taken at fixed times during the day. A maintenance dose should be taken in one sitting after breakfast.

In thyrotoxicosis, depending on the severity of the disease, the drug is prescribed in a dose of 20-40 mg/day for 3-6 weeks. After normalization of thyroid function (usually after 3-8 weeks) we switch to taking a maintenance dose of 5-20 mg/day. From this time, additional intake of levothyroxine sodium is recommended.

In preparation for surgical treatment of thyrotoxicosis, 20-40 mg/day are prescribed until euthyroidism is achieved. From this time, additional administration of levothyroxine sodium is recommended. In order to reduce the time required to prepare for surgery, beta-adrenoblockers and iodine preparations are additionally prescribed.

In preparation for radioactive iodine treatment, 20-40 mg/day are prescribed until euthyroidism is achieved.

In therapy during the latent period of radioiodine action, depending on the severity of the disease, 5-20 mg/day are prescribed until the onset of radioiodine action (4-6 months).

In long-term thyrotoxic maintenance therapy, Thyrozole is prescribed in doses of 1.25-2.5-10 mg/day with additional administration of sodium levothyroxine in small doses. In the treatment of thyrotoxicosis the duration of therapy is 1.5 to 2 years.

In order to prevent thyrotoxicosis when administration of iodine preparations (including cases of iodine containing radiopaque agents) in the presence of latent thyrotoxicosis, autonomous adenomas or thyrotoxicosis in anamnesis Thirozole is prescribed in dose 10-20 mg/day and potassium perchlorate 1 g/day for 8-10 days before administration of iodine containing agents.

In children aged 3 to 17 years, Tyrosol is prescribed in an initial dose of 0.3-0.5 mg/kg body weight in 2-3 equal divided doses daily. Maximum recommended dose for children with body weight over 80 kg is 40 mg/day. Maintenance dose is 0.2-0.3 mg/kg/day. If necessary, levothyroxine sodium is prescribed additionally.

The use in children aged 0 to 3 years is not recommended.

In pregnancy the drug is prescribed in minimal doses: single dose 2.5 mg, daily 10 mg.

In cases of hepatic impairment, the drug is prescribed in the lowest effective dose under close medical supervision.

In preparation for surgery in patients with thyrotoxicosis, treatment with the drug is carried out until euthyroidism is achieved for 3-4 weeks prior to the planned day of surgery (in some cases longer) and ends the day before surgery.

Interaction

The effects of thiamazole may be impaired if the drug is administered after high-dose iodine-containing radiopaque agents.

Iodine deficiency enhances the effects of thiamazole.

. In patients taking Thyrozole® for thyrotoxicosis the doses of cardiac glycosides (digoxin and digitoxin), aminophylline may require decreasing, and the doses of warfarin and other anticoagulants – coumarin and indandion derivatives may increase (pharmacodynamic interaction) after achieving euthyroid state (normalization of serum thyroid hormones).

The drugs lithium, beta-adrenoblockers, reserpine, amiodarone increase the effect of thiamazole (requires correction of its dose).

Concomitant use with sulfonamides, sodium methamisole and myelotoxic drugs increases the risk of leukopenia.

Leukogen and folic acid when used concomitantly with thiamazole decrease the risk of leukopenia.

Gentamicin increases the antithyroid effect of thiamazole.

There are no data on the effect of other drugs on the pharmacokinetics and pharmacodynamics of the drug. However, it should be borne in mind that in thyrotoxicosis the metabolism and elimination of substances is accelerated. Therefore, in some cases it is necessary to adjust the dose of other drugs.

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Special Instructions

In patients with significant thyroid gland enlargement narrowing the tracheal lumen, Thyrozole® is prescribed for short periods in combination with sodium levothyroxine, since prolonged use may cause goiter enlargement and even greater tracheal compression. The patient should be closely monitored (control of TSH level and tracheal lumen).

The peripheral blood count should be monitored regularly during treatment with the drug.

Thiamazole and thiourea derivatives may decrease the sensitivity of thyroid tissue to radiation therapy.

If during treatment with the drug, sore throat, difficulty swallowing, fever, signs of stomatitis, or furunculosis (possible symptoms of agranulocytosis) suddenly occur, discontinue the drug and see a physician immediately.

If during treatment, subcutaneous bleeding or bleeding of unclear genesis, generalized skin rash and pruritus, persistent nausea or vomiting, jaundice, severe epigastric pain, and marked weakness require discontinuation.

If treatment is stopped early, relapse of the disease is possible.

The appearance or worsening of the course of endocrine ophthalmopathy is not a side effect of adequate treatment with Thyrozole® properly performed.

In rare cases, late-onset hypothyroidism may occur after completion of treatment, which is not a side effect of the drug, but is associated with inflammatory and destructive processes in the thyroid tissue occurring as part of the underlying disease.

Impact on driving and operating machinery

Tiamazole has no effect on the ability to drive vehicles and operate machinery.

Contraindications

• High sensitivity to thiamazole and thiourea derivatives;
• agranulocytosis during previous therapy with carbimazole or thiamazole;
• granulocytopenia (including history of thiamazole).
• granulocytopenia (including history);
• cholestasis before starting treatment;
• tampmazole therapy in combination with levothyroxine during pregnancy;
• children under 3 years of age.

Tyrosol® contains lactose; therefore, its use is not recommended in patients with rare hereditary diseases associated with galactose intolerance, lactase deficiency, or glucose-galactose malabsorption syndrome.

The drug should be used with caution in very large goiter with tracheal constriction (only short-term treatment in preparation for surgery), in hepatic insufficiency.

Side effects

Blood system disorders: infrequent – agranulocytosis (symptoms may appear even weeks and months after the start of treatment and lead to the need to withdraw the drug); very rare – generalized lymphadenopathy, thrombocytopenia, pancytopenia.

Endocrine system disorders: very rarely – insulin autoimmune syndrome with hypoglycemia.

Nervous system disorders: rare – reversible change in taste sensation, dizziness, very rare – neuritis, polyneuropathy.

Digestive system disorders: very rare – increase of salivary glands, vomiting.

Hepatic and biliary tract disorders: very rare – cholestatic jaundice and toxic hepatitis.

Skin and subcutaneous tissue disorders: very rare – generalized skin rashes, alopecia, lupus-like syndrome.

Allergic reactions: skin manifestations (itching, redness, rashes).

Muscular system disorders: often – slowly progressing arthralgia without clinical signs of arthritis.

General reactions: rare – fever, weakness, weight gain.

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Overdose

Symptoms: with long-term use of the drug in high doses, subclinical and clinical hypothyroidism may develop, as well as increased size of the thyroid gland due to increased levels of TSH in the blood. This can be avoided by reducing the dose of the drug until euthyroidism is achieved or, if necessary, by additional prescription of levothyroxine sodium.

In general, spontaneous recovery of thyroid function is observed after discontinuation of Thyrozole®. Administration of thiamazole in very high doses (about 120 mg/day) may lead to development of myelotoxic effects. The drug should be used in such doses only with special indications (severe forms of the disease, thyrotoxic crisis).

The treatment: withdrawal of the drug, gastric lavage, symptomatic therapy, if necessary, switching to an antithyroid drug of another group.

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