Metizol

Package leaflet: Information for the patient

Warning! Keep the leaflet. Information on the immediate packaging in a foreign language.
Metizol, 5 mg, tablets
Thiamazolum
Please read the entire leaflet carefully before taking this medicine, as it contains
important information for the patient.

• Keep this leaflet for future reference.
• If you have any questions, please consult your doctor or pharmacist.
• This medicine has been prescribed for a specific individual. Do not give it to others. This medicine may harm others, even if their symptoms are the same.
• If you experience any adverse reactions, including any adverse reactions not listed in this leaflet, inform your doctor, pharmacist, or nurse. See section 4.

Table of contents of the leaflet:

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

1. What Metizol is and what it is used for

Metizol is a medicine that inhibits the production of thyroid hormones. However, it does not affect the amount of already produced hormones or their release; therefore, its effects become apparent only after several days of treatment.
Due to these properties, Metizol is used in hyperthyroidism (regardless of its type), thyroid storm, preparation for thyroidectomy, and as an adjunctive treatment in radioactive iodine therapy.

2. Important information before using Metizol

When not to use Metizol

• if the patient is allergic to thiamazole, substances structurally related to thiamazole (thiourea derivatives), or any of the other ingredients of this medicine (listed in section 6);
• if the patient has been diagnosed with reduced numbers of certain blood cells (granulocytopenia);
• if the patient has cholestasis diagnosed before starting treatment with Metizol;
• if the patient previously experienced bone marrow damage during treatment with thiamazole or carbimazole;
• if the patient previously developed pancreatitis (acute pancreatitis) after receiving thiamazole or carbimazole.

Concomitant use of thiamazole and thyroid hormones should not be used in pregnant women.
Warnings and precautions
Before starting treatment with Metizol, discuss this with your doctor.
If the patient previously experienced mild allergic reactions to thiamazole, such as allergic skin rashes or itching, inform the doctor – the doctor will decide whether the patient may take Metizol.
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In case of a large goitre causing breathing difficulties, discuss this with the doctor, as the goitre may enlarge during treatment with Metizol. The doctor may decide to use the medicine for a shorter period and will regularly monitor the patient during treatment.
Before starting treatment, the doctor will order blood count tests.
Immediately consult a doctor if symptoms such as oral mucosal inflammation, sore throat, or fever occur. These symptoms may indicate a serious adverse effect of the medicine – agranulocytosis (a marked deficiency of certain types of white blood cells responsible for immune responses in the body). These symptoms usually occur within the first weeks of treatment, but may appear even after several months of therapy or when restarting treatment. If such symptoms occur, the doctor will order a blood count test and may decide to discontinue treatment with Metizol.
Immediately consult a doctor if the patient develops fever or abdominal pain, as these may be symptoms of pancreatitis (acute pancreatitis). Discontinuation of Metizol may be necessary.
If high doses of Metizol (approximately 120 mg per day) are required, the doctor will order regular blood tests, as bone marrow damage is possible. If toxic effects on the bone marrow occur, the doctor may decide to stop treatment and, if necessary, prescribe another medicine.
If goitre enlargement occurs during treatment with Metizol or if thyroid function becomes excessively reduced, the doctor may modify the dose of Metizol and, if necessary, additionally prescribe thyroid hormones.
Metizol may harm the unborn child. If the patient could become pregnant, she should use a reliable method of contraception from the start of treatment and throughout therapy.
During treatment, the development or worsening of a condition known as endocrine ophthalmopathy may occur, but this is unrelated to treatment with Metizol.
During treatment with Metizol, weight gain may occur. This is a normal bodily response. Metizol affects thyroid hormones, which regulate energy consumption in the body.
Children and adolescents
The safety and efficacy of Metizol have not been studied in children under 2 years of age.
Metizol may be used in children and adolescents aged 3 to 17 years (see section 3). For additional information, consult a doctor.
Metizol with other medicines
Inform your doctor or pharmacist about all medicines the patient is currently taking or has recently taken, as well as any medicines the patient plans to take, including those available without a prescription.
The effect of thiamazole is reduced by:

• iodine;
• medicines containing iodine (e.g. amiodarone – a medicine used to treat heart rhythm disorders);
• radiographic contrast agents. Thiamazole reduces the uptake of radioactive iodine by the thyroid gland. If anticoagulant medicines (preventing blood clotting) are used, inform the doctor, as normalization of thyroid function due to Metizol may affect the action of these medicines. This may also apply to other medicines. As thyroid hormone levels return to normal due to treatment with Metizol, blood concentrations of certain

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concomitantly administered medicines may change. Therefore, dosage adjustment of concomitantly administered medicines may be necessary.
Metizol with food and drink
Metizol may be taken independently of meals.
Pregnancy, breastfeeding, and effects on fertility
Metizol may harm the unborn child.
If the patient could become pregnant, she should use a reliable method of contraception from the start of treatment and throughout therapy.
If the patient is pregnant, suspects she may be pregnant, or is planning to have a child, she should immediately consult a doctor.
Continuation of treatment with Metizol during pregnancy may be necessary if potential benefits outweigh risks to the mother and fetus.
During pregnancy, concomitant use of Metizol and thyroid hormones is not permitted.
During breastfeeding, Metizol may be used only in low doses, up to 10 mg per day. However, thyroid hormones must not be taken concomitantly. The infant of a patient treated with Metizol who is breastfeeding should be regularly examined by a doctor monitoring thyroid function in the infant.
Patients receiving high doses of Metizol must not breastfeed.
Driving and operating machinery
Metizol has a minor influence on the ability to drive and operate machinery.
This medicine may cause dizziness (see section 4). Patients experiencing this adverse effect should not drive or operate machinery until the symptom has completely resolved.
Metizol contains monohydrate lactose
If the patient has previously been diagnosed with intolerance to certain sugars, the patient should consult a doctor before taking the medicine.

3. How to use Metizol

This medicine should always be taken as directed by the physician. In case of doubt, consult a doctor or pharmacist.

Recommended dosage
The physician determines the dosage individually for each patient depending on the severity of hyperthyroidism and the size of goitre.
The initial daily dose is usually 40 mg to 60 mg (8 to 12 tablets), administered in 3 or 4 divided doses. This dosage should be maintained until thyroid function is suppressed (usually 2–3 weeks, although sometimes this dosage must be continued for 8 weeks or longer). Subsequently, the dose should be gradually reduced to a maintenance dose of usually 5 mg to 20 mg (1 to 4 tablets) per day. This dose may be taken as a single daily dose or in 2 divided doses.
In the treatment of thyroid storm, the medicine is initially administered at a dose of 100 mg (20 tablets), followed by 30 mg (6 tablets) every 8 hours.
Treatment of hyperthyroidism with Metizol usually lasts from 6 months to 2 years.
For preparation prior to surgical removal of the thyroid gland, the medicine is usually administered for 3–4 weeks preceding the procedure.

Elderly patients:
Dosage adjustment is not necessary.

Use in children and adolescents (aged 3 to 17 years)
In children and adolescents aged 3 years and older, the dose is adjusted according to the patient's body weight.
At the beginning of treatment, the usual dose is 0.5 mg/kg body weight, divided into 2 or 3 equal doses.
Later, the physician may recommend reducing the dose. The total daily dose should not exceed 40 mg.
Use is not recommended in children under 2 years of age.

Patients with renal impairment:
Dosage adjustment is not necessary.

Patients with hepatic impairment:
In case of impaired liver function or liver disease, inform the physician.
In such cases, it may be necessary to reduce the dose of Metizol.

Metizol should be taken regularly.

Use of a higher than recommended dose of Metizol
If a higher than recommended dose of Metizol is taken, consult a physician immediately. The physician will initiate appropriate management, including, among others, induction of vomiting, gastric lavage, administration of activated charcoal, and symptomatic treatment.
In case of overdose, symptoms may include: nausea, vomiting, muscle pain, constipation, headache, menstrual disorders in women, decreased body temperature, enlargement or appearance of goitre (swelling in the front of the neck), excessive drowsiness or lethargy, fatigue, weight gain, excessive dryness of the skin, and insomnia.

Missed dose of Metizol
If a dose of Metizol is missed at the scheduled time, take it as soon as possible. However, if the time for the next dose is approaching, skip the missed dose.
Do not take a double dose to make up for a missed dose.

Discontinuation of Metizol
Premature discontinuation of treatment with Metizol may result in worsening of hyperthyroidism.
In case of any doubts regarding the use of this medicine, consult a doctor or pharmacist.

4. Possible adverse reactions

Like all medicines, this medicine can cause adverse reactions, although not everyone will experience them.
Adverse reactions may occur:
Very commonly (may occur in more than 1 in 10 people)
Commonly (may occur in up to 1 in 10 people)
Uncommonly (may occur in less than 1 in 100 people)
Rarely (may occur in up to 1 in 1,000 people)
Very rarely (may occur in up to 1 in 10,000 people)
Frequency not known (frequency cannot be estimated from the available data)
If any of the following adverse reactions occur, stop taking the medicine and
contact your doctor immediately:

• Symptoms such as: inflammation of the oral mucosa, sore throat, fever, which may indicate an uncommon adverse reaction – agranulocytosis (a marked decrease in the number of certain types of white blood cells).

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These symptoms may appear within the first weeks of treatment or only after several
weeks or months of taking the medicine.
In addition, the following adverse reactions may occur:
Very common adverse reactions:

• Allergic skin reactions of varying severity (itching, rash, urticaria) – usually mild and resolve during continued treatment.

Common adverse reactions:

• Joint pain, which may occur even after several months of therapy;

Uncommon adverse reactions:

• Taste disturbances (altered sense of taste, loss of taste) – these symptoms may resolve after discontinuation of treatment, which may take several weeks;
• Fever.

Rare adverse reactions:

• Thrombocytopenia (reduced number of platelets; may manifest as excessive bleeding, e.g. after procedures, nosebleeds, frequent bruising, presence of blood in stool or urine, petechiae on the skin);
• Pancytopenia (reduction in the number of all blood cells);
• Generalized lymphadenopathy (enlarged lymph nodes), decreased blood glucose concentration (caused by disturbances in glucose regulation processes);
• Neuritis, polyneuropathy (nerve damage, may manifest as numbness and tingling in the hands, feet, and face);
• Salivary gland swelling;
• Cholestatic jaundice (manifesting as yellowing of the skin, mucous membranes, and whites of the eyes) and toxic hepatitis – these symptoms usually resolve after discontinuation of the medicine;
• Severe forms of skin allergic reactions, including generalized dermatitis;
• Hair loss;
• Drug-induced systemic lupus erythematosus (an immune-mediated disease; may manifest, among others, as fatigue, loss of appetite, and development of a characteristic butterfly-shaped rash on the face).

Frequency not known:

• Dizziness;
• Pancreatitis (acute inflammation of the pancreas).

Children and adolescents
The type, frequency, and severity of adverse reactions in children and adolescents are similar to
those observed in adults.
Reporting of adverse reactions
If any adverse symptoms occur, including any not listed in this leaflet, inform your doctor, pharmacist, or nurse. Adverse reactions can be reported directly to the Department of Monitoring of Adverse Drug Reactions of the Office for Registration of Medicinal Products, Medical Devices and Biocidal Products
Al. Jerozolimskie 181C
02-222 Warsaw
Phone: +48 22 49 21 301
Fax: +48 22 49 21 309
Website: https://smz.ezdrowie.gov.pl.
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Reporting adverse reactions helps to provide more information on the safety of the medicine.

5. How to store Metizol

Keep in the original packaging.
Keep the medicine out of the 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 stated month.
Medicines must not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. Following this advice helps protect the environment.

6. Contents of the packaging and other information

What Metizol contains

• The active substance is thiamazole. Each tablet contains 5 mg of thiamazole.
• The other ingredients are: monohydrate lactose, potato starch, povidone, talc, magnesium stearate.

What Metizol looks like and contents of the pack
Metizol is a white, round, biconvex tablet, embossed with the mark "M" on one side and smooth on the other.
The pack contains 50 tablets (2 blisters of 25 tablets each).
For further detailed information, please contact the marketing authorisation holder or the parallel importer.
Marketing authorisation holder in Bulgaria, the country of export:
Mylan EOOD, Office building "Serdika Offices", Sitnyakovo Blvd., No.48, fl. 7, 1505 Sofia, Bulgaria
Manufacturer:
ICN Polfa Rzeszów S.A., Przemysłowa 2, 35-959 Rzeszów, Poland
Parallel importer:
Delfarma Sp. z o.o., Św. Teresy od Dzieciątka Jezus 111, 91-222 Łódź, Poland
Repackaged in:
Delfarma Sp. z o.o., Św. Teresy od Dzieciątka Jezus 111, 91-222 Łódź, Poland
Marketing authorisation number in Bulgaria, the country of export: 9900341
Parallel import authorisation number: 100/22
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