Medication Description: Mercazolil (Mercazolilum)

MERKAZOLIL (Mercazolilum). 1-Methyl-2-mercaptoimidazole.

Synonyms: Tiamazole, Antiroid, Basolan, Danantizol, Favistan, Mercazole, Methimazole, Methothyrin, Tapazole, Thiamazole, Thycapzol, Thymidazol, etc.

A white or yellowish crystalline powder with a slight peculiar odor and bitter taste. Easily soluble in water (1: 7, 5) and alcohol (1:10).

It is a synthetic antithyroid (thyreostatic) substance. Like other substances of this group, it causes a decrease in the synthesis of thyroxin in the thyroid gland, due to which it has a specific therapeutic effect upon its hyperfunction. Like other antithyroid substances, it also lowers basal metabolism.

The drug accelerates the excretion of iodides from the thyroid gland, inhibits the activity of enzyme systems involved in the oxidation of iodides to iodine, which leads to inhibition of thyroglobulin iodization and delayed conversion of diiodotyrosine to thyroxin. In addition, a violation of the synthesis of thyroxin may depend on the reaction of methylthiouracil with free iodine formed in the thyroid gland from iodides.

Apply with diffuse toxic goiter (mild, moderate and severe forms).

Assign inside after a meal: with mild and moderate forms of thyrotoxicosis, 0.005 g 3 to 4 times a day, and in severe form, 0.01 g 3 to 4 times a day.

After the onset of remission (after 3–6 weeks), the daily dose is reduced every 5–10 days by 0.005–0.01 g and the minimum maintenance doses are gradually selected (0.005 g once a day, every other day or once every 3 days) to obtain a stable therapeutic effect.

If the treatment is stopped too early, the disease may relapse.

There is evidence of the feasibility of a combination of mercazole with lithium carbonate.

Higher doses for adults inside: single 0.01 g, daily 0.04 g.

Mercazolil is usually well tolerated in therapeutic doses. It should, however, be applied under the supervision of a physician; once a week it is necessary to perform a blood test, since in some cases leukopenia may develop; nausea, vomiting, abnormal liver function, goitrogenic effect, medical hypothyroidism, skin rash, joint pain are also possible. With the development of side effects reduce the dose or stop further administration of the drug.

In patients receiving mercazole when preparing for an operation, an increase in bleeding of the thyroid gland is possible, therefore, having reached remission or a significant improvement in the patient's condition, mercazole is canceled, iodine preparations are prescribed; the operation is performed after 2 to 3 weeks.

Contraindicated in pregnant women, during lactation, with severe leukopenia and granulocytopenia, nodular forms of goiter (with the exception of severe progressive diseases in which the possibility of surgery is temporarily excluded).

It should not be combined with mercazole with drugs that can cause leukopenia (amidopyrine and its analogues, sulfonamides, etc.).

Form release: tablets of 0.005 g.

Storage: List B. In a dry dark place.