Espa carb® [Carbimazole]

Pharmacological properties

carbimazole, depending on the dosage, inhibits the incorporation of iodine into tyrosine, and, consequently, the additional synthesis of thyroid hormones. this property makes possible the symptomatic treatment of hyperthyroidism regardless of its etiology. Does carbimazole, in addition, affect the natural course of the disease with an immunologically determined form of hyperthyroidism (bazedovy disease), that is, does it slow down the immunopathogenetic process that underlies the disease, it is currently impossible to determine with full confidence. carbimazole does not affect the release of already synthesized thyroid hormones. this in some cases explains the different duration of the latent period of the drug to normalize the concentration of thyroxine and triiodothyronine in the blood plasma, that is, to a clinical improvement. the drug also does not affect hyperthyroidism due to the release of hormones after the destruction of thyroid cells, for example, after radiotherapy or with thyroiditis.

Pharmacokinetics Carbimazole is rapidly and completely absorbed and immediately after absorption it turns into its active form - thiamazole. After taking 15 mg of carbimazole for 24–72 min, a maximum plasma level of 150 ng / nl is reached.

The binding of thiamazole to plasma proteins can be neglected. Thiamazole accumulates in the thyroid gland, where it is slowly metabolized and, since its duration of action is directly more related to the concentration of the substance in the thyroid gland than to its T_½ from plasma, this leads to an extension of antithyroid activity. Which determines the almost 24-hour duration of action of a single dose and makes it possible to use the drug 1 time per day. The kinetics of thiamazole, according to currently available data, does not depend on the state of thyroid function.

T_½ from the body is about 3 hours, with insufficient liver function, it lengthens. Thiamazole is excreted in both urine and bile. But bile excretion is negligible, which makes it possible to conclude enterohepatic circulation. Over 24 hours, kidneys secrete 70% of Thiamazole, of which only a small amount is unchanged. There are currently no data on the pharmacological activity of metabolites.

Indications

Impaired thyroid function associated with overproduction of its hormones (hyperthyroidism). preparation for thyroidectomy with hyperthyroidism. therapy before and after treatment with radioactive iodine.

Application

Espa-carb is used only for hyperthyroidism, which has been confirmed by laboratory tests.

Adults The dose at the beginning of treatment should be 20-60 mg, which must be titrated depending on the function of the thyroid gland before reaching the patients euthyroid state in order to reduce the risk of excessive treatment and, as a result, hypothyroidism. Further treatment is carried out in one of two ways.

Maintenance therapy: the final dose, as a rule, is 5-15 mg / day, which can be taken as a single daily dose. Therapy is continued for at least 6-18 months. They recommend constant monitoring of thyroid function simultaneously with appropriate dose selection to maintain the euthyroid state.

Blocking-substitution scheme: initial doses of 20-60 mg / day are supported, sodium levothyroxine 50-150 μg / day is additionally prescribed to prevent hypothyroidism. Therapy lasts for at least 6–18 months.

Elderly patients. If there are no contraindications or warnings, then such patients do not require special dosing.

Contraindications

Increased individual sensitivity to carbimazole, Thiamazole or other components of the drug.severe disorders of the blood system, severe liver failure, cholestasis. simultaneous use of drugs of radioactive iodine. additional therapy with the use of thyroid hormones during pregnancy.

Side effects

In the frequency analysis of the occurrence of side effects, the following categories were identified: very often (≥10%); often (≥1% –10%); infrequently (≥0.1% –1%); rarely (≥0.01% –0.1%); very rarely (0.01%); unknown (frequency not estimated due to lack of data).

On the part of the blood and lymphatic system

Infrequently: about 0.3-0.6% of cases develop agranulocytosis, which can also occur weeks or months after the start of therapy and forces you to refuse to take the drug. In most cases, agranulocytosis arbitrarily disappears. According to recent data, the use of granulocyte colony stimulation factors (granulocyte colony-stimulating factor filgrastim) is confirmed for the treatment of drug-induced agranulocytosis. However, the use of such factors should occur in agreement with the hematologist.

Very rarely: thrombocytopenia, pancytopenia, aplastic anemia, hemolytic anemia.

Endocrine system

Due to the increased dosage, subclinical or clinical hypothyroidism may occur, as well as goiter growth, which is associated with an increase in the level of thyroid-stimulating hormone (TSH). In this regard, after reaching the euthyroid state, the dose of Espa-carb should be reduced and / or sodium levothyroxine should be additionally used. It is inexpedient to completely stop taking Espa-carb and continue therapy with thyroid hormones.

An increase in goiter during therapy with Espa-carb with a suppressed TSH level should be taken as a consequence of the underlying disease and not be treated with an additional intake of thyroid hormones.

After a single thyreostatic therapy, there is a small percentage of the occurrence of posthypothyroidism. In such cases, we are not talking about the side effects of the drug, but about inflammatory and destructive processes in the thyroid parenchyma within the framework of the underlying disease.

On the part of the organs of vision

The occurrence or worsening of endocrine orbitopathy is possible regardless of the course of the thyroid gland disease: such a complication, in itself, is not a reason for changing the therapeutic program (thyreostatics, surgery, radioactive iodine), and should not be taken as a side effect of a qualified therapy.

From the nervous system: headache.

From the digestive tract: nausea, minor gastrointestinal upset.

Common disorders: fever, malaise, bruises.

Infrequently: drug fever, impaired taste (dysgeusia, ageusia) or impaired sense of smell, which disappear after cessation of treatment, and normalization can last several weeks.

Very rarely: arthralgia and myalgia, which develop, as a rule, slowly and continue after many months of prolonged therapy. There are no clinical signs of joint inflammation.

Generalized lymphadenopathy, arthritis, nephritis, acute swelling of the salivary gland, vasculitis, neuritis and polyneuropathy, insulin-autoimmune syndrome (with a marked decrease in blood glucose).

When taking Espa-carb, due to the reduction of energy demand pathologically increased during hyperthyroidism, a (generally desired) increase in body weight may occur. Patients should be informed that with an improvement in the picture of the disease, the energy requirement of the body is normalized.

From the hepatobiliary system

Very rarely: cholestatic jaundice or toxic hepatitis. In general, the symptoms disappear after stopping the drug.Clinically hidden signs of cholestasis during treatment should be distinguished from plasma activity of gamma-glutamyl transferase already elevated before the start of therapy as a sign of enzymatic induction due to hyperthyroidism, as well as an increase in alkaline phosphatase or its bone isoenzymes.

On the part of the skin and its derivatives

Very often: allergic manifestations on the skin (itching, rash, urticaria) of a periodic nature. In most cases, they are mild and often disappear with continued therapy.

Very rarely: severe forms of manifestations of generalized dermatitis. Hair loss, drug-induced lupus erythematosus.

From the musculoskeletal system: in isolated cases - myopathy. In patients in whom muscle pain occurs after treatment with carbimazole, the level of CPK should be constantly monitored.

Hypersensitivity reactions: Quinckes edema, multisystem hypersensitivity reactions (cutaneous vasculitis, reactions from the liver, lungs and kidneys).

From the vessels: bleeding.

special instructions

When the first signs and symptoms of liver dysfunction occur (pain in the upper abdomen, lack of appetite, general itching), the drug should be discontinued and liver function monitoring should be immediately conducted.

Carbimazole should be used with caution in patients with mild to moderate hepatic impairment.

In severe liver dysfunction, treatment should be discontinued. T_½ may increase with impaired liver function.

During the administration of radioactive iodine for this period, carbimazole treatment should be discontinued.

Patients who can not follow the instructions regarding the use of the drug or cannot be examined regularly should not take carbimazole.

In patients in whom seizures or memory impairment are possible, a blood test should be performed regularly.

Patients with rare hereditary forms of galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome should not take this drug.

Precautions are necessary for patients with intrathoracic goiter, which may worsen initial carbimazole treatment. Tracheal obstruction may occur due to intrathoracic goiter.

The use of carbimazole in non-pregnant women of reproductive age is possible only with a risk / benefit assessment.

There is a risk of cross-allergy between carbimazole, thiamazole and propylthiouracil.

Use during pregnancy and lactation. Carbimazole crosses the placenta. If the mother’s dose within the standard range and the state of her thyroid gland are monitored, there is no evidence of thyroid dysfunction in newborns. Studies have noted that the incidence of congenital malformations is higher in those children whose mothers have noted untreated hyperthyroidism than those who have been treated with carbimazole.

However, very rarely congenital developmental deficiencies are noted after the use of carbimazole or its active metabolite methimazole during pregnancy. A possible relationship between the occurrence of malformations, in particular atresia of the choanas and congenital aplasia of cutis, which cannot be excluded with the transplacental influence of carbimazole and methimazole. Thus, the use of carbimazole during pregnancy and in women of reproductive age is possible only when the expected benefit to the mother outweighs the potential risk to the fetus.

There have also been reports of cases of impaired renal function, skull, congenital malformations of the cardiovascular system, umbilical hernia, gastrointestinal malformations, umbilical malformations and atresia of the duodenum. Therefore, carbimazole should be prescribed during pregnancy only when propylthiouracil is not suitable.If carbimazole must be used during pregnancy, the dose should be corrected depending on the clinical condition of the patient. You can use the drug in low doses and stop treatment 3-4 weeks before the date of birth to reduce the risk of neonatal complications. It is impossible to stop treatment during pregnancy, since a very small amount of thyroxine crosses the placenta in the last trimester of pregnancy.

Additional treatment with thyroid hormones is prohibited (a blocking-replacement scheme is not used, since a small amount of thyroxine can pass through the placenta in the last trimester of pregnancy).

During therapy with carbimazole, continued feeding is possible, however, it is allowed to take only in low doses (up to 10 mg / day) without additional intake of thyroid hormones. In this case, it is necessary to control the function of the thyroid gland of the child.

Children. There is not enough experience with the use of carbimazole in children, so the drug is not prescribed for patients of this age category.

The ability to influence the reaction rate when driving vehicles and working with other mechanisms. The effect on the ability to drive vehicles or work with other mechanisms is unknown.

Interactions

There is insufficient data regarding the interaction of carbimazole with other drugs. carbimazole should be used with caution with agents that may cause the development of agranulocytosis. since carbimazole is an antagonist of vitamin K, the effect of anticoagulants may be enhanced. an increase in theophylline levels in blood plasma and the development of toxicity are possible if patients receive therapy with antithyroid drugs without reducing the dose of theophylline. there is a risk of cross-allergy between carbimazole, thiamazole and propylthiouracil.

Overdose

Cases of overdose are not described.

Storage conditions

In the original packaging at a temperature not exceeding 25 ° C.