Euthyrox n 100

Package leaflet: Information for the user

Euthyrox N 100, 100 micrograms, tablets
Euthyrox N 150, 150 micrograms, tablets
Euthyrox N 200, 200 micrograms, tablets
Levothyroxinum natricum
Please read the entire leaflet carefully before taking this medicine, as it contains
important information for the patient.

• Keep this leaflet, as you may need to read it again.
• If you have any further questions, please consult your doctor or pharmacist.
• This medicine has been prescribed for a specific individual. Do not pass it on to others. This medicine may harm other people, even if their symptoms are the same.
• If you experience any adverse effects, including any not listed in this leaflet, please inform your doctor or pharmacist. See section 4.

Table of contents

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

1. What Euthyrox N is and what it is used for

Levothyroxine sodium, the active substance in Euthyrox N, is a synthetic thyroid hormone
used in the treatment of thyroid diseases and disorders of thyroid function.
It has the same action as the thyroid hormones naturally present in the body.
Euthyrox N 100; Euthyrox N 150 and Euthyrox N 200 are used:

• for the treatment of goitre in patients (mainly adults) with normally functioning thyroid gland,
• to prevent recurrence of goitre in patients after surgery,
• to replace the deficiency of natural thyroid hormones when the thyroid gland does not produce sufficient amounts,
• to suppress tumour growth in patients with thyroid cancer.

Euthyrox N 100 is also used to normalize thyroid hormone levels in patients
who are receiving antithyroid drugs due to excessive production of thyroid hormones.
Euthyrox N 100, Euthyrox N 150 and Euthyrox N 200 may also be used in tests assessing
thyroid function.

2. Important information before using Euthyrox N

When not to use Euthyrox N

• if the patient is allergic to the active substance or to any of the other ingredients of this medicine (listed in section 6),
• if the patient has untreated hypopituitarism or if thyroid hormones are being produced in excess (untreated hyperthyroidism),
• if the patient has adrenal insufficiency and is not receiving appropriate replacement therapy,
• if the patient has recently suffered a myocardial infarction, myocarditis, or acute inflammation of all layers of the heart (pancarditis).
  Euthyrox N must not be used concomitantly with antithyroid drugs if the patient is pregnant (see "Pregnancy and breastfeeding" below).

Warnings and precautions
Before starting treatment with this medicine, inform your doctor if any of the following conditions are present:

• inadequate blood flow in the blood vessels of the heart (angina pectoris),
• heart failure,
• rapid or irregular heartbeat,
• arterial hypertension,
• atherosclerosis.
  These disorders must be adequately controlled before initiating treatment with Euthyrox N. During treatment with Euthyrox N, regular monitoring of thyroid hormone levels is necessary. If there is any uncertainty whether the patient has any of the above conditions or if these conditions are untreated, consult a doctor.

Before starting treatment with Euthyrox N, inform your doctor if the patient has adrenal insufficiency.
The doctor will perform appropriate tests to determine whether the patient has disorders of adrenal or pituitary function, or a certain type of thyroid dysfunction with uncontrolled overproduction of thyroid hormones (autonomous thyroid function), as specific treatment may be required before initiating Euthyrox N therapy.

When initiating levothyroxine treatment in preterm infants with very low birth weight, blood pressure should be monitored regularly, as a sudden drop in arterial blood pressure (so-called circulatory collapse) may occur.

If it becomes necessary to switch from one levothyroxine-containing medicine to another, thyroid hormone balance may be disturbed. Consult your doctor if you have any questions regarding changing medications. Close clinical and biochemical monitoring is required during the transition period. Inform your doctor if any adverse effects occur, as dose adjustment may be necessary.

Thyroid hormones should not be used for weight reduction. Taking them will not lead to weight loss if thyroid hormones are maintained at appropriate levels. Increasing the dose of the medicine without consulting a doctor may result in severe and life-threatening adverse effects. Do not take high doses of levothyroxine in combination with other weight-loss medicines such as amfepramone, cathine, or phenylpropanolamine due to the possible increased risk of severe and life-threatening adverse effects.

Talk to your doctor:

• if the patient is perimenopausal or postmenopausal; the doctor may recommend more frequent, regular monitoring of thyroid function due to the risk of osteoporosis;
• in case of diabetes or if taking anticoagulant medicines (medicines that reduce blood clotting);
• when starting or stopping orlistat treatment or changing orlistat therapy (a medicine used in the treatment of obesity); more frequent monitoring and appropriate dose adjustment may be necessary;
• in case of psychotic disorders, the doctor may recommend more frequent monitoring and appropriate dose adjustment;
• if laboratory tests to measure thyroid hormone levels are planned, the patient should inform the doctor or laboratory staff about current or recent biotin intake (also known as vitamin H, vitamin B7, or vitamin B8). Biotin may affect laboratory test results. Depending on the type of test, results may be falsely elevated or falsely decreased due to biotin intake. The doctor may advise the patient to discontinue biotin before laboratory testing. It is also important to remember that other products the patient may be taking, such as multivitamin preparations or supplements for hair, skin, and nails, may also contain biotin. This may affect laboratory test results. If the patient is taking such products, they should inform the doctor or laboratory staff (see section "Euthyrox N and other medicines").

Euthyrox N and other medicines
Inform your doctor about all medicines currently or recently taken, as well as any medicines the patient plans to take.
If taking any of the following medicines, inform your doctor, as Euthyrox N may affect their action:

• antidiabetic medicines (medicines that lower blood glucose levels): Euthyrox N may reduce the effectiveness of antidiabetic medicines, so additional monitoring of blood glucose levels may be necessary, especially at the beginning of Euthyrox N treatment. During Euthyrox N therapy, adjustment of the antidiabetic medicine dose may be required;
• anticoagulant medicines (coumarin derivatives): Euthyrox N may enhance the effect of these medicines, increasing the risk of bleeding, especially in elderly patients. Therefore, regular monitoring of blood coagulation parameters may be necessary, particularly at the beginning of Euthyrox N treatment. During Euthyrox N therapy, adjustment of the coumarin derivative anticoagulant dose may be required.

When taking any of the following medicines concomitantly with Euthyrox N, it is essential to follow the recommended time intervals between administration of the medicines:

• bile acid sequestrants and cholesterol-lowering agents (cholestyramine or colestipol): Euthyrox N should be taken 4 to 5 hours before these medicines, as they may inhibit the intestinal absorption of Euthyrox N;
• antacids, sucralfate (used in the treatment of gastric and intestinal ulcers), other aluminium-containing medicines, iron-containing medicines, calcium-containing medicines: Euthyrox N should be taken at least 2 hours before these medicines, as otherwise they may reduce the effectiveness of Euthyrox N.

If any of the following medicines are being taken, inform your doctor, as they may reduce the effectiveness of Euthyrox N:

• propylthiouracil (an antithyroid medicine),

• glucocorticosteroids (anti-allergic and anti-inflammatory medicines),

• beta-blockers (medicines that lower blood pressure, also used in the treatment of heart diseases),

• sertraline (an antidepressant),

• sevelamer (a medicine that reduces phosphate levels, used in patients with chronic kidney failure),

• tyrosine kinase inhibitors (medicines used in cancer treatment),

• chloroquine or proguanil (medicines used in the treatment or prevention of malaria),

• medicines that induce certain liver enzymes, such as barbiturates (sedatives and hypnotics), carbamazepine (an anticonvulsant also used to relieve certain types of pain and control mood disorders), herbal medicines containing St. John's wort (Hypericum perforatum),

• oestrogen-containing medicines, used in hormone replacement therapy during or after menopause or for contraception,

• proton pump inhibitors (such as omeprazole, esomeprazole, pantoprazole, rabeprazole, and lansoprazole) used to reduce gastric acid production, which may impair levothyroxine absorption from the intestine and reduce its effectiveness. If the patient is taking levothyroxine during treatment with proton pump inhibitors, the doctor should monitor thyroid function and, if necessary, modify the dose of Euthyrox N,

• orlistat (a medicine used in the treatment of obesity).

If any of the following medicines are being taken, inform your doctor, as they may enhance the effect of Euthyrox N:

• salicylates (medicines used to relieve pain and reduce fever),
• dicoumarol (a medicine that reduces blood clotting),
• high-dose furosemide, above 250 mg (a diuretic),
• clofibrate (a medicine that reduces blood lipid levels).

If taking orlistat, inform your doctor. Concomitant use of Euthyrox N and orlistat may lead to hypothyroidism and/or worsening control of hypothyroidism.
If taking protease inhibitors (medicines used in the treatment of HIV infections, e.g. ritonavir, indinavir, lopinavir) or phenytoin (an anticonvulsant), which may affect the action of Euthyrox N, inform your doctor.
In such cases, thyroid hormone testing and dose adjustment may be necessary.
If taking amiodarone (a medicine used to treat cardiac arrhythmias), inform your doctor, as this medicine may affect thyroid function.
Inform your doctor that you are taking Euthyrox N if diagnostic testing with iodine-containing contrast agents is required, as such testing involves injection of substances that may affect thyroid function.
If the patient is currently or recently taking biotin, they must inform the doctor or laboratory staff if thyroid hormone laboratory tests are to be performed. Biotin may affect laboratory test results (see "Warnings and precautions").

Euthyrox N with food and drink
If the diet includes soy-containing products, inform your doctor, especially if the amount of such products consumed changes. Soy-containing products may reduce the intestinal absorption of Euthyrox N, and therefore appropriate dose adjustment of Euthyrox N may be necessary.

Pregnancy and breastfeeding
If the patient is pregnant or breastfeeding, suspects she may be pregnant, or is planning to become pregnant, she should consult a doctor or pharmacist before using this medicine.
During pregnancy, Euthyrox N should be continued under medical supervision, as dose adjustment may be necessary.
If Euthyrox N was used concomitantly with an antithyroid medicine to treat excessive thyroid hormone production, the doctor will advise discontinuing Euthyrox N after conception.
Antithyroid medicines must not be used concomitantly during pregnancy.
Thyroid function suppression tests should not be performed during pregnancy.
During breastfeeding, Euthyrox N should be continued as recommended by the doctor. The concentration of levothyroxine passing into breast milk is too low to affect the infant.

Driving and operating machinery
No studies have been conducted on the effect of the medicine on the ability to drive vehicles or operate machinery. No effect of Euthyrox N on the ability to drive and operate machinery is expected when used according to recommendations, as levothyroxine is identical to the naturally occurring form.

Euthyrox N contains sodium
The medicine contains less than 1 mmol (23 mg) of sodium per tablet, i.e. the medicine is considered "sodium-free".

3. How to use Euthyrox N

This medicine should always be taken exactly as directed by the doctor. If in doubt, consult
the doctor or pharmacist.
The doctor will determine the appropriate individual dose for each patient based on clinical
and laboratory assessments. Treatment usually starts with a low dose, which is increased every 2–4
weeks until the full, individually adjusted dose is reached.
During the first weeks of treatment, laboratory tests will be necessary to allow the doctor to adjust
the appropriate dose.
Typical dose ranges are shown in the table below. Lower doses may be sufficient for individuals who:

• are elderly,
• have heart disease,
• have severe or long-standing hypothyroidism,
• have low body weight or giant goitre.

Use in children and adolescents
In newborns and infants with congenital hypothyroidism, a condition characterised by insufficient production of thyroid hormones, where rapid hormone replacement is essential, the recommended initial dose is 10 to 15 micrograms/kg body weight per day during the first 3 months.
Thereafter, the physician will individually adjust the dose based on clinical evaluation and concentrations of thyroid hormones and TSH.

Administration method
Euthyrox N is intended for oral use.
The single daily dose should be taken in the morning on an empty stomach (at least half an hour before breakfast), preferably with a small amount of liquid, e.g. half a glass of water.

For infants, the entire daily dose of Euthyrox N should be administered once daily, at least half an hour before the first meal of the day. Immediately before administration, the tablet should be crushed and mixed with a small amount of water. The resulting suspension should then be given with an additional small amount of liquid.
A fresh suspension should be prepared each time before administration.

Duration of treatment
The duration of treatment may vary depending on the reason for which Euthyrox N is prescribed. The physician will discuss with each patient individually how long the medication should be taken.
Most patients need to take Euthyrox N for life.
If a dose adjustment is necessary, the physician may prescribe Euthyrox N with a different strength.

Use of a higher than recommended dose of Euthyrox N
If a higher than recommended dose is taken, symptoms such as rapid heartbeat, restlessness, agitation, or involuntary movements may occur. In patients with pre-existing neurological disorders, such as epilepsy, isolated seizures have been observed.
Overdose may cause hyperthyroidism and lead to symptoms of acute psychosis.
In such cases, medical advice should be sought immediately.

Missed dose of Euthyrox N
Do not take a double dose to make up for a missed dose. On the following day, resume taking the usual prescribed dose.
If you have any further questions regarding the use of this medicine, consult your doctor or pharmacist.

4. Possible adverse reactions

Like all medicines, this medicine can cause adverse reactions, although not everyone will experience them.
Euthyrox N is identical to the natural thyroid hormone. Therefore, if Euthyrox N is taken at the dose prescribed by the doctor and if laboratory tests are performed regularly, adverse reactions should not occur.
You should stop taking the medicine immediately and consult your doctor without delay if sudden symptoms of hypersensitivity to the components of Euthyrox N occur: swelling of the face, tongue or throat, difficulty swallowing, difficulty breathing (angioedema); respiratory system reactions (worsening shortness of breath); skin reactions (rash, urticaria). The frequency of these adverse reactions is unknown.
If a higher dose of Euthyrox N than recommended is taken, or if the recommended dose is poorly tolerated (e.g. when the dose is increased too rapidly), some of the following adverse reactions may occur: irregular or rapid heartbeat, palpitations, angina-like chest pain, headache, weakness or muscle cramps, hot flushes (feeling of warmth and facial flushing), fever, vomiting, menstrual disorders, pseudotumor cerebri (increased intracranial pressure), tremor, motor restlessness, sleep disturbances, sweating, weight loss, diarrhoea.
If any of the above symptoms occur, you should contact your doctor.
The doctor may decide to interrupt treatment for a few days or reduce the daily dose until symptoms resolve.
Reporting of adverse reactions
If you experience any adverse reactions, including any not listed in this leaflet, inform your doctor or pharmacist. 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
Adverse reactions can also be reported to the marketing authorization holder.
By reporting adverse reactions, additional information on the safety of the medicine can be collected.

5. How to store Euthyrox N

Keep the medicine out of the sight and reach of children.
Do not use Euthyrox N after the expiry date stated on the blister or carton, following the wording "Expiry date (EXP)". The expiry date refers to the last day of the specified month.
Do not store above 25°C.
To protect from light, keep the blister in the outer packaging.
Medicines must not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. Such measures help protect the environment.

6. Contents of the pack and other information

What Euthyrox N contains

• The active substance is sodium levothyroxine. Each tablet contains 100 micrograms, 150 micrograms, or 200 micrograms of sodium levothyroxine.
• The other ingredients are: maize starch, citric acid, gelatin, sodium croscarmellose, magnesium stearate, and mannitol (E 421).

What Euthyrox N looks like and contents of the pack
Euthyrox N tablets are whitish, round, flat, with a dividing score on both sides, bevelled edges, and marked on one side:
Euthyrox N 100: EM 100
Euthyrox N 150: EM 150
Euthyrox N 200: EM 200
The tablet can be divided into equal doses.
Euthyrox N is available in packs containing 50 or 100 tablets in a cardboard box.
Not all pack sizes may be marketed.

Marketing Authorisation Holder
Merck Sp. z o.o.
Al. Jerozolimskie 142B
02-305 Warsaw, Poland
tel. +48 22 53 59 700
Logo of the marketing authorisation holder

Manufacturer
Merck Healthcare KGaA
Frankfurter Strasse 250
64293 Darmstadt, Germany
FAMAR HEALTH CARE SERVICES MADRID, S.A.U.
Avda. Leganés, 62
Alcorcón, 28923 Madrid, Spain

Manufacturer/Importer
Merck Healthcare KGaA
Frankfurter Strasse 250
64293 Darmstadt, Germany