Package leaflet: Information for the patient

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

Keep this leaflet so that you can read it again if necessary.
If you have any questions, consult your doctor or pharmacist.
This medicine has been prescribed for a specific individual. Do not pass it on to others. The medicine may harm another person, even if their symptoms are identical.
If the patient experiences any adverse reactions, including any not listed in this leaflet, inform your doctor or pharmacist. See section 4.

Table of contents of the leaflet:

What Metizol is and what it is used for
Important information before taking Metizol
How to take Metizol
Possible side effects
How to store Metizol
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 hormones already produced 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 a supportive agent in radioactive iodine therapy.

2. Important information before using Metizol

When not to use Metizol

if the patient is allergic to thiamazole, substances structurally similar to thiamazole (thiourea derivatives), or any of the other ingredients of this medicine (listed in section 6);
if the patient has been diagnosed with a reduced number of certain blood cells (granulocytopenia);
if the patient has cholestatic jaundice diagnosed before starting treatment with Metizol;
if in the past the patient experienced bone marrow damage after treatment with thiamazole or carbimazole;
if in the past the patient developed pancreatitis (acute pancreatitis) following administration of thiamazole or carbimazole.

Concomitant use of thiamazole and thyroid hormones should not be used in pregnant women.
Warnings and precautions
Before starting to take Metizol, discuss this with your doctor.
If mild allergic reactions to thiamazole occurred in the past, such as allergic skin rashes or itching, inform your doctor – the doctor will decide whether the patient can take Metizol.
In cases of a large goitre causing breathing difficulties, discuss this with your 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 contact your 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 several months after starting therapy or when restarting treatment. If such symptoms occur, the doctor will order a blood count test and may decide to discontinue use of Metizol.
Immediately contact your doctor if the patient develops fever or abdominal pain, as these may be symptoms of pancreatitis (acute pancreatitis). It may be necessary to stop using Metizol.
If very high doses of Metizol (approximately 120 mg per day) are required, the doctor will order regular blood tests, as there is a risk of bone marrow damage. If toxic effects on the bone marrow occur, the doctor may decide to discontinue treatment and, if necessary, prescribe another medicine.
If during treatment with Metizol the goitre enlarges or thyroid function becomes excessively reduced, the doctor may adjust 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 occurrence or worsening of a condition called endocrine ophthalmopathy may occur; this is unrelated to treatment with Metizol.
Weight gain may occur during treatment with Metizol. This is a normal bodily response. Metizol affects thyroid hormones, which regulate energy expenditure 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 your doctor.
Metizol with other medicines
Inform your doctor or pharmacist about all medicines currently used or 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 cardiac arrhythmias);
radiographic contrast agents. Thiamazole reduces the uptake of radioactive iodine by the thyroid gland. If anticoagulant medicines (preventing blood clotting) are used, inform your 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 in blood return to normal due to treatment with Metizol, blood concentrations of certain concomitantly administered medicines may change. Therefore, dosage adjustment of concomitantly used medicines may be necessary.

Metizol with food and drink
Metizol can be taken independently of meals.
Pregnancy, breastfeeding and 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 her doctor.
Continuation of treatment with Metizol during pregnancy may be necessary if potential benefits outweigh the risks to 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 simultaneously. The infant of a patient treated with Metizol who is breastfeeding should be regularly examined by a doctor, who will monitor thyroid function in the infant.
Patients receiving high doses of Metizol must not breastfeed.
Driving and operating machinery
Metizol has 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 lactose monohydrate
If the patient has previously been diagnosed with intolerance to certain sugars, the patient should consult their doctor before taking this medicine.

3. How to use the medicine Metizol

This medicine should always be taken exactly as prescribed by the doctor. If in doubt, consult
your doctor or pharmacist.
Recommended dose
The doctor determines the dose individually for each patient depending on the severity of
hyperthyroidism and the size of the 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 even longer). Then, the dose should be gradually reduced to a maintenance dose, 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.
For the treatment of thyroid crisis, the medicine is initially given 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.
In preparation for thyroidectomy, the medicine is usually used for 3–4 weeks prior to surgery.
Elderly patients:
There is no need to change the dosage.
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 body weight.
Initially, a dose of 0.5 mg/kg body weight is usually given, divided into 2 or 3 equal doses.
Later, the doctor may recommend reducing the dose. The total daily dose should not exceed 40 mg.
Use in children under 2 years of age is not recommended.
Patients with renal function disorders:
There is no need to change the dosage.
Patients with hepatic function disorders:
If there are disorders of liver function or liver disease, inform your doctor.
In such cases, it may be necessary to reduce the dose of Metizol.
Metizol should be taken regularly.
Taking more than the recommended dose of Metizol
If more than the recommended dose of Metizol is taken, consult a doctor immediately. The doctor will initiate appropriate management, including inducing vomiting, gastric lavage, administration of activated charcoal, and symptomatic treatment.
In case of overdose, symptoms may include, among others: nausea, vomiting, muscle pain, constipation, headache, in women menstrual disorders, decreased body temperature, enlargement or appearance of goitre (swelling in the front part of the neck), excessive sleepiness or drowsiness, fatigue, weight gain, excessive dryness of the skin, and insomnia.
Missed dose of Metizol
If a dose of the medicine is missed at the scheduled time, take it as soon as possible. However, if it is almost time for the next dose, skip the missed dose.
Do not take a double dose to make up for a missed dose.
Stopping the use of Metizol
Premature discontinuation of treatment with Metizol may lead to worsening of hyperthyroidism.
If in doubt about the use of the medicine, consult your doctor or pharmacist.

4. Possible adverse reactions

Like all medicines, this medicine can cause adverse reactions, although they do not occur in everyone.
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 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 mucous membranes of the mouth, sore throat, fever, which may indicate an uncommon adverse reaction – agranulocytosis (a marked decrease in the number of certain types of white blood cells). These symptoms may appear within the first weeks of treatment or even after several weeks or months of taking the medicine.

In addition, the following adverse reactions may occur:
Very commonly occurring adverse reactions:

Allergic skin reactions of varying severity (itching, rash, urticaria) – usually mild and resolve during continued use of the medicine.
Commonly occurring adverse reactions:
Joint pain, which may appear even after several months of treatment;

Uncommonly occurring adverse reactions:

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

Very rarely occurring 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, petechial hemorrhages on the skin);
Pancytopenia (reduction in the number of all blood cells);
Generalized lymphadenopathy (enlargement of 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 (manifested by 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 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 reactions occur, including any not listed in this leaflet, inform your doctor or pharmacist. Adverse reactions can be reported directly to the Department of Monitoring 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.
Reporting adverse reactions allows the collection of further information on the safety of the medicine.

5. How to store the medicine Metizol

Store in the original packaging.
Keep the medicine 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 stated month.
Medicines must not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. Such practices help protect the environment.

6. Contents of the pack and other information

What Metizol contains

The active substance is thiamazole.
The other ingredients are: lactose monohydrate, potato starch, povidone, talc, magnesium stearate.

What Metizol looks like and contents of the pack
Metizol is a white, round, biconvex tablet, marked with an embossed "M" on one side and smooth on the other.
The pack contains 50 tablets in PVC/Al blisters packed in a cardboard box.
For further 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.
ul. Przemysłowa 2
35-959 Rzeszów
Poland
Parallel Importer:
InPharm Sp. z o.o.
ul. Strumykowa 28/11
03-138 Warsaw
Repackaged in:
InPharm Sp. z o.o. Services sp. k.
ul. Chełmżyńska 249
04-458 Warsaw
Marketing Authorisation Number in Bulgaria, the country of export: 9900341
Parallel Import Authorisation Number: 188/22