Thirozol

Leaflet attached to the packaging: information for the user

Warning! The leaflet should be kept. Information on the immediate packaging in a foreign language.

Thyrozol, 20 mg, coated tablets

Thiamazolum

You should carefully read the contents of the leaflet before using the medicine, as it contains important information for the patient.

• You should keep this leaflet, so that you can read it again if necessary.
• In case of any doubts, you should consult a doctor or pharmacist.
• This medicine has been prescribed to a specific person. It should not be given to others. The medicine may harm another person, even if the symptoms of their disease are the same.
• If the patient experiences any side effects, including any side effects not listed in this leaflet, they should tell their doctor, pharmacist, or nurse. See section 4.

Table of contents of the leaflet

• 1. What is Thyrozol and what is it used for
• 2. Important information before taking Thyrozol
• 3. How to take Thyrozol
• 4. Possible side effects
• 5. How to store Thyrozol
• 6. Contents of the packaging and other information

1. What is Thyrozol and what is it used for

The medicine contains thiamazol. It inhibits the excessive production of thyroid hormones in the thyroid gland, regardless of the cause.

Thyrozol is used to treat excessive production of thyroid hormones:

• when it is necessary to take the medicine to treat a thyroid gland that produces hormones in excess, especially in the case of a small goiter (swelling in the front of the neck) or no goiter,
• when thyroid surgery is planned,
• when treatment with radioactive iodine is planned, especially in cases of very high production of thyroid hormones,
• after treatment with radioactive iodine until the effects of the treatment are fully apparent.

Thyrozol is used to prevent excessive production of thyroid hormones before planned exposure to iodine, for example, before an examination using iodine-containing contrast agents:

• when a slight increase in thyroid hormone production is detected without accompanying symptoms,
• when there are certain areas in the thyroid gland that produce hormones (autonomous goiters),
• when excessive production of thyroid hormones has occurred in the past.

2. Important information before taking Thyrozol

When not to take Thyrozol

• if the patient is allergic (hypersensitive) to thiamazol, substances similar to thiamazol (thionamide derivatives) or any of the other ingredients of this medicine (listed in section 6),
• if laboratory tests reveal a decrease in the number of certain blood cells (granulocytopenia),
• if bile flow is impaired before starting treatment with Thyrozol,
• if bone marrow damage has been detected after treatment with thiamazol or carbimazol in the past,
• if acute pancreatitis has occurred after administration of thiamazol or carbimazol in the past.

Warnings and precautions

Before starting treatment with Thyrozol, you should discuss it with your doctor or pharmacist.

If you have had mild allergic reactions to thiamazol in the past, such as allergic rashes or skin itching, you should talk to your doctor, who will decide whether you can take Thyrozol.

In the case of a large goiter (swelling in the front of the neck) that makes breathing difficult, you should talk to your doctor, as the goiter may increase during treatment with Thyrozol.

The doctor may decide to use the medicine for a short period and with regular monitoring during treatment.

You should consult your doctor immediately if you experience symptoms such as fever, fatigue, weight loss, and muscle and joint pain. These may be symptoms of vasculitis (inflammation of blood vessels). In such a case, the doctor may stop the treatment if necessary. Usually, these symptoms disappear after stopping the treatment.

You should stop taking Thyrozol and consult your doctor immediately if you experience symptoms such as inflammation of the mucous membrane of the mouth, sore throat, or fever. The cause may be a serious decrease in the number of certain blood cells (agranulocytosis). This can happen especially in the first few weeks of treatment and may lead to serious consequences.

You should consult your doctor immediately if you experience fever or abdominal pain, as these may be symptoms of pancreatitis (acute pancreatitis). It may be necessary to stop taking Thyrozol.

Thyrozol may harm an unborn child. If you may become pregnant, you should use a reliable method of contraception from the start of treatment and during therapy.

In the case of very high production of excess thyroid hormones, it may be necessary to take very high doses of Thyrozol (over 120 mg per day). In such a situation, the doctor will periodically perform blood tests, as bone marrow damage is possible. If this happens, the doctor may decide to stop the treatment and, if necessary, prescribe another medicine.

If the goiter increases or thyroid function is excessively weakened during treatment with Thyrozol, the doctor may modify the dose of Thyrozol. However, such situations may also occur in the natural course of the disease. Similarly, a certain type of eye disease (endocrine orbitopathy) may occur or worsen, which is not related to treatment with Thyrozol.

During treatment with Thyrozol, it is possible to gain weight. This is a normal reaction of the body. Thyrozol affects thyroid hormones, which control energy consumption in the body.

Thyrozol and other medicines

Iodine intake affects the action of Thyrozol. The doctor will determine the dose of Thyrozol, taking into account the iodine intake and thyroid function in the individual patient.

If you are taking anticoagulant medicines (preventing blood clotting), you should tell your doctor, as the normalization of thyroid function under the influence of Thyrozol may affect the action of these medicines. The same applies to other medicines.

You should tell your doctor or pharmacist about all medicines you are currently taking or have recently taken, as well as any medicines you plan to take.

Pregnancy and breastfeeding

Thyrozol may harm an unborn child.

If you may become pregnant, you should use a reliable method of contraception from the start of treatment and during therapy.

If you are pregnant, think you may be pregnant, or plan to have a child, you should consult your doctor immediately. It may be necessary to continue treatment with Thyrozol during pregnancy if the potential benefits outweigh the risk to the mother and fetus.

Thyrozol passes into human milk. The doctor will decide whether it is necessary to take Thyrozol while breastfeeding. If necessary, you can take only a small dose of up to 10 mg of thiamazol.

The doctor will regularly monitor how the newborn's thyroid is working.

Driving and using machines

Thyrozol does not affect the ability to drive and use machines.

Important information about some ingredients of Thyrozol

If you are intolerant to some sugars, you should tell your doctor, as Thyrozol contains lactose monohydrate.

The medicine contains less than 1 mmol (23 mg) of sodium per tablet, which means the medicine is considered "sodium-free".

3. How to take Thyrozol

This medicine should always be taken according to the doctor's recommendations. In case of doubts, you should consult your doctor.

Thyrozol is available in the following doses: 5 mg, 10 mg, and 20 mg.

Recommended dose

The doctor will determine the dose individually, depending on the severity of the disease. Usually, the following doses are recommended.

• Adults The initial dose is 10 mg to 40 mg of Thyrozol per day (or more in some patients) and is used until the thyroid starts to function properly. The maintenance dose is 5 mg to 20 mg of Thyrozol per day in combination with thyroid hormones or 2.5 mg to 10 mg of Thyrozol per day without thyroid hormones.
• Use in children and adolescents (from 3 to 17 years) The initial dose is 0.5 mg of Thyrozol per kilogram of body weight per day. Then, the doctor will decide whether a smaller maintenance dose is sufficient and whether additional use of thyroid hormones is necessary.

Use in children (under 2 years)

Thyrozol is not recommended for use in children under 2 years of age.

If there is a risk of excessive production of thyroid hormones after a diagnostic test using an iodine-containing contrast agent, the doctor may recommend taking 10 mg to 20 mg of Thyrozol per day in combination with perchlorate for about 10 days (until the iodine-containing contrast agent is eliminated from the body).

If small doses are needed, 5 mg tablets are available.

Patients with liver disease

In case of liver function disorders or liver disease, you should tell your doctor. In such cases, it will be necessary to reduce the dose of Thyrozol.

Patients with kidney disease

In case of kidney function disorders or kidney disease, you should tell your doctor. In such cases, it will be necessary to reduce the dose of Thyrozol.

Duration of treatment

The duration of treatment may vary depending on the reason for taking Thyrozol.

The doctor will explain how long you should take the medicine. Usually, the duration of treatment is as follows:

• treatment of excessive thyroid hormone production (without surgery): from 6 months to 2 years,
• preoperative treatment: 3-4 weeks before surgery,
• treatment before administration of radioactive iodine: until thyroid function is normalized,
• treatment after administration of radioactive iodine: 4-6 months, until the effects of radioactive iodine therapy are apparent.

Administration

Tablets should be taken in the morning, after breakfast, and washed down with a small amount of liquid, e.g., half a glass of water. The tablet can be divided into equal doses.

If you are taking several tablets a day, you can also divide them into several portions and take them at regular intervals throughout the day.

Taking a higher dose of Thyrozol than recommended

In case of accidental ingestion of a higher dose of the medicine than recommended, there should be no problem. If you have taken a higher dose several times, you should contact your doctor as soon as possible.

You may experience intolerance to cold, fatigue, dry skin, constipation, weight gain, slow heart rate, and goiter growth. The doctor may recommend changing the dose of Thyrozol or prescribing additional thyroid hormones to avoid goiter growth.

Missing a dose of Thyrozol

You should not take a double dose to make up for a missed dose. The next day, you should take the same dose as usual.

If you have any further doubts about taking this medicine, you should consult your doctor or pharmacist.

4. Possible side effects

Like all medicines, Thyrozol can cause side effects, although not everybody gets them.

During treatment with Thyrozol, the following side effects may occur, in some cases even after several months of treatment.

Very common(may occur in more than 1 in 10 people)

• Skin reactions of varying severity (rash, itching, itching blisters). In most cases, they are mild and disappear during continued treatment with Thyrozol.

Common(may occur in up to 1 in 10 people)

• Joint pain.

Uncommon(may occur in up to 1 in 100 people)

• In case of symptoms such as inflammation of the mucous membrane of the mouth, sore throat, or fever, you should consult your doctor immediately. These may be symptoms of a serious decrease in the number of certain blood cells (agranulocytosis).

Rare(may occur in up to 1 in 1,000 people)

• Taste disorders or loss of taste.
• Fever.

Very rare(may occur in up to 1 in 10,000 people)

• Decreased platelet count (thrombocytopenia), decreased count of all blood cells (pancytopenia), lymph node disease (generalized lymphadenopathy).
• Disorders of hormones regulating blood sugar levels, manifested by decreased blood sugar levels (autoimmune insulin syndrome).
• Inflammation or irritation of nerves (neuritis, polyneuropathy).
• Salivary gland swelling.
• Liver function disorders or liver inflammation (cholestatic jaundice, toxic hepatitis). Usually, symptoms disappear after stopping treatment.
• Acute allergic skin reactions that can occur all over the body, including blistering skin reactions (Stevens-Johnson syndrome), hair loss, inflammatory autoimmune skin and connective tissue disease (lupus erythematosus).

Frequency not known(frequency cannot be estimated from the available data)

• Pancreatitis (acute pancreatitis).
• Vasculitis (inflammation of blood vessels).

Children and adolescents

Side effects in children and adolescents are similar to those observed in adults.

Reporting side effects

If you experience any side effects, including any side effects not listed in this leaflet, you should tell your doctor, pharmacist, or nurse. Side effects can be reported directly to the Department of Monitoring of Adverse Reactions to Medicinal Products of the Office for Registration of Medicinal Products, Medical Devices, and Biocidal Products;

Al. Jerozolimskie 181C

02-222 Warsaw

tel.: +48 22 49 21 301

fax: +48 22 49 21 309

website: https://smz.ezdrowie.gov.pl

By reporting side effects, you can help gather more information on the safety of the medicine.

5. How to store Thyrozol

The medicine should be stored out of sight and reach of children.

Do not use this medicine after the expiry date stated on the packaging. The expiry date refers to the last day of the specified month.

Translation of some information on the immediate packaging:

Verwendbar bis und Ch.-B. siehe Randprägung – Expiry date and batch number see edge printing

Do not store above 25°C.

Medicines should not be disposed of via wastewater or household waste. You should ask your pharmacist how to dispose of medicines that are no longer used. This will help protect the environment.

6. Contents of the packaging and other information

What Thyrozol contains

• The active substance of the medicine is thiamazol. Each coated tablet contains 20 mg of thiamazol.
• The other ingredients are: tablet core: colloidal silica anhydrous, magnesium stearate, hypromellose, talc, cellulose, powder, corn starch, lactose monohydrate, sodium carboxymethylcellulose; coating: dimeticone 100, macrogol 400, hypromellose, titanium dioxide (E 171), and iron oxide (E 172).

What Thyrozol looks like and what the pack contains

Brown, biconvex, round with a dividing line on both sides.

Available in packs containing 25 or 50 tablets.

For more detailed information, you should contact the marketing authorization holder or the parallel importer.

Marketing authorization holder in Germany, the country of export:

Merck Healthcare Germany GmbH

Waldstraße 3, 64331 Weiterstadt, Germany

Manufacturer:

Merck Healthcare KGaA

Frankfurter Straße 250, 64293 Darmstadt, Germany

Parallel importer:

Delfarma Sp. z o.o.

ul. Św. Teresy od Dzieciątka Jezus 111, 91-222 Łódź

Repackaged by:

Delfarma Sp. z o.o.

ul. Św. Teresy od Dzieciątka Jezus 111, 91-222 Łódź

German export license number: 13478.02.00

Parallel import license number: 197/25

This medicine is authorized in the Member States of the European Economic Area under the following names:

Bulgaria: Thyrozol

Czech Republic: Thyrozol

Estonia: Thyrozol

France: Thyrozol

Germany: Thyrozol

Latvia: Thyrozol

Lithuania: Thyrozol

Poland: Thyrozol

Romania: Thyrozol

Slovakia: Thyrozol

Date of approval of the leaflet: 06.06.2025

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