Euthirox N 25

Leaflet accompanying the packaging: information for the user

Euthyrox N 25, 25 micrograms, tablets
Euthyrox N 50, 50 micrograms, tablets
Euthyrox N 75, 75 micrograms, tablets
Euthyrox N 125, 125 micrograms, tablets
Euthyrox N 175, 175 micrograms, tablets
Sodium levothyroxine

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

• You should keep this leaflet, so that you can read it again if you need to.
• If you have any further questions, ask your doctor or pharmacist.
• This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their symptoms are the same as yours.
• If you experience any side effects, including any not listed in this leaflet, please inform your doctor or pharmacist. See section 4.

Contents of the leaflet

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

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

Sodium levothyroxine, the active substance of Euthyrox N, is a synthetic thyroid hormone intended for the treatment of thyroid diseases and disorders.
It has the same effect as the thyroid hormones that occur naturally in the body.
Euthyrox N 25; Euthyrox N 50; Euthyrox N 75; Euthyrox N 125 and Euthyrox N 175 are used:

• to treat goiter in patients (mainly adults) with normal thyroid function,
• to prevent goiter recurrence in patients after surgery,
• to supplement the lack of natural thyroid hormones when the thyroid gland does not produce enough hormones,
• to inhibit tumor growth in patients with thyroid cancer.

Euthyrox N 25, Euthyrox N 50 and Euthyrox N 75 are also used to adjust thyroid hormone levels in patients who are taking antithyroid medications due to excessive thyroid hormone production.

2. Important information before taking Euthyrox N

When not to take Euthyrox N

• if you are allergic to the active substance or any of the other ingredients of this medicine (listed in section 6.),
• if you have untreated hypopituitarism or if thyroid hormones are produced in excess (untreated hyperthyroidism),
• if you have adrenal insufficiency and you are not receiving appropriate replacement therapy,
• if you have recently had a myocardial infarction, myocarditis, or acute pancreatitis. Euthyrox N should not be taken simultaneously with antithyroid medications if you are pregnant (see "Pregnancy and breastfeeding" below).

Warnings and precautions

Before starting treatment with this medicine, you should inform your doctor about the following diseases:

• insufficient blood flow in the coronary arteries (angina pectoris),
• heart failure,
• rapid and irregular heart rate,
• high blood pressure,
• atherosclerosis. It is necessary to adjust these disorders before starting treatment with Euthyrox N. During treatment with Euthyrox N, it is necessary to frequently monitor thyroid hormone levels. If you have any doubts about whether you have any of the above diseases or if they are not treated, you should consult your doctor.

Before starting treatment with Euthyrox N, you should tell your doctor if you have adrenal insufficiency.
Your doctor will perform the necessary tests to determine if you have adrenal or pituitary disorders or a certain type of thyroid disorder with uncontrolled excessive thyroid hormone production (autonomous thyroid function), as in such cases, appropriate treatment may be necessary before starting Euthyrox N.
When starting treatment with levothyroxine in premature infants with very low birth weight, it is necessary to regularly monitor blood pressure, as a sudden drop in blood pressure (so-called circulatory collapse) may occur.
In the event of a need to change the medication to another levothyroxine-containing medication, a disruption of thyroid hormone balance may occur. You should consult your doctor if you have any questions about changing medications. During the transition period, close monitoring of clinical and biochemical parameters is necessary. You should inform your doctor if you experience any side effects, as it may be necessary to increase or decrease the dose.
Thyroid hormones are not used to reduce weight. Taking them will not reduce weight if thyroid hormones are at the proper level. Increasing the dose of the medicine without consulting a doctor may lead to serious and life-threatening side effects. You should not take high doses of levothyroxine in combination with other weight loss medications, such as amfepramone, clobenzorex, and phentermine, due to the possible increased risk of serious and life-threatening side effects.
You should talk to your doctor:

• if you are in menopause or postmenopause; your doctor may then recommend more frequent, regular monitoring of thyroid function due to the risk of osteoporosis;
• if you have diabetes or are taking anticoagulant medications (medications that reduce blood clotting);
• if you are starting, stopping, or changing treatment with orlistat (a medication used to treat obesity); more frequent monitoring and dose adjustment may be necessary;
• if you have psychotic disorders, your doctor may recommend more frequent monitoring and dose adjustment;
• if you are to undergo laboratory tests to check thyroid hormone levels, you should inform your doctor or laboratory staff if you are currently taking or have recently taken biotin (also known as vitamin H, vitamin B7, or vitamin B8). Biotin may affect laboratory test results. Depending on the type of test, the results may be falsely elevated or falsely decreased due to biotin intake. Your doctor may recommend that you stop taking biotin before undergoing laboratory tests. You should also remember that other products you are taking, such as multivitamins or supplements for hair, skin, and nails, may also contain biotin. This may affect laboratory test results. If you are taking such products, you should inform your doctor or laboratory staff (see "Warnings and precautions").

Euthyrox N and other medications

You should tell your doctor about all medications you are currently taking or have recently taken, as well as any medications you plan to take.
If you are taking any of the following medications, you should inform your doctor, as Euthyrox N may affect their action:

• antidiabetic medications (medications that lower blood sugar levels): Euthyrox N may weaken the action of antidiabetic medications, so additional monitoring of blood sugar levels may be necessary, especially at the beginning of treatment with Euthyrox N. During treatment with Euthyrox N, it may be necessary to adjust the dose of antidiabetic medication;
• anticoagulant medications (coumarin derivatives): Euthyrox N may enhance the action of these medications, which may increase the risk of bleeding, especially in the elderly. Therefore, regular monitoring of blood clotting parameters may be necessary, especially at the beginning of treatment with Euthyrox N. During treatment with Euthyrox N, it may be necessary to adjust the dose of anticoagulant medication.

If you are taking any of the following medications, you should inform your doctor, as they may affect the action of Euthyrox N:

• medications that bind bile acids and reduce high cholesterol levels (cholestyramine or colestipol): Euthyrox N should be taken 4 to 5 hours before taking these medications, as they may inhibit the absorption of Euthyrox N from the gut;
• antacids (used to relieve indigestion), sucralfate (used to treat stomach and intestinal ulcers), other medications containing aluminum, medications containing iron, medications containing calcium: Euthyrox N should be taken at least 2 hours before taking these medications, as they may weaken the action of Euthyrox N.

If you are taking any of the following medications, you should inform your doctor, as they may weaken the action of Euthyrox N:

• propylthiouracil (an antithyroid medication),
• glucocorticoids (anti-allergic and anti-inflammatory medications),
• beta-adrenergic blockers (medications that lower blood pressure, also used to treat heart diseases),
• sertraline (an antidepressant medication),
• sevelamer (a medication that reduces phosphate levels, used in patients with chronic kidney failure),
• tyrosine kinase inhibitors (medications used to treat cancer),
• chloroquine or proguanil (medications used to treat or prevent malaria),
• medications that activate certain liver enzymes, such as barbiturates (sedatives, sleep aids), carbamazepine (an antiepileptic medication also used to alleviate certain types of pain and control mood disorders), medications containing St. John's Wort (some herbal medications),
• medications containing estrogens, used in hormone replacement therapy during menopause and postmenopause or to prevent pregnancy,
• proton pump inhibitors (such as omeprazole, esomeprazole, pantoprazole, rabeprazole, and lansoprazole) used to reduce stomach acid production, which may weaken the absorption of levothyroxine from the gut and make it less effective. If you are taking levothyroxine while being treated with proton pump inhibitors, your doctor should monitor your thyroid function and adjust the dose of Euthyrox N if necessary,
• orlistat (a medication used to treat obesity).

If you are taking any of the following medications, you should inform your doctor, as they may enhance the action of Euthyrox N:

• salicylates (medications used to relieve pain and reduce fever),
• dicumarol (a medication that reduces blood clotting),
• furosemide in high doses, above 250 mg (a diuretic medication),
• clofibrate (a medication that reduces lipid levels in the blood).

If you are taking orlistat, you should inform your doctor. Taking Euthyrox N and orlistat simultaneously may cause hypothyroidism and/or worsen hypothyroidism control.
If you are taking protease inhibitors (medications used to treat HIV infections, such as ritonavir, indinavir, lopinavir) or phenytoin (an antiepileptic medication), which may affect the action of Euthyrox N, you should inform your doctor.
In this case, it may be necessary to perform a thyroid hormone test and adjust the dose of Euthyrox N.
If you are taking amiodarone (a medication used to treat heart rhythm disorders), you should inform your doctor, as this medication may affect thyroid function.
You should inform your doctor about taking Euthyrox N if you need to undergo a diagnostic test involving the administration of a contrast agent containing iodine, as this test involves the administration of an injection that affects thyroid function.
If you are currently taking or have recently taken biotin, you must inform your doctor or laboratory staff if you are to undergo laboratory tests for thyroid hormones. Biotin may affect laboratory test results (see "Warnings and precautions").

Euthyrox N with food and drink

If your diet includes soy products, you should inform your doctor, especially if you change the amount of these products you consume. Soy products may reduce the absorption of Euthyrox N from the small intestine, and therefore, it may be necessary to adjust the dose of Euthyrox N.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, think you may be pregnant, or plan to have a child, you should consult your doctor or pharmacist before taking this medicine.
During pregnancy, you should continue taking Euthyrox N under medical supervision, as it may be necessary to adjust the dose of the medicine.
If Euthyrox N was taken simultaneously with an antithyroid medication for the treatment of excessive thyroid hormone production, your doctor will recommend that you stop taking Euthyrox N after becoming pregnant.
During pregnancy, you should not take antithyroid medications simultaneously.
During pregnancy, you should not undergo diagnostic tests that involve the suppression of thyroid function.
During breastfeeding, you should continue taking Euthyrox N as recommended by your doctor. The level of levothyroxine that passes into breast milk is too small to affect the baby.

Driving and using machines

No studies have been conducted on the effect of the medicine on the ability to drive and use machines. It is not expected that Euthyrox N will have any effect on the ability to drive and use machines when taken as recommended, as levothyroxine is identical to the form that occurs naturally.

Euthyrox N contains sodium

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 Euthyrox N

This medicine should always be taken as directed by your doctor. If you have any doubts, you should consult your doctor or pharmacist.
Your doctor will determine the appropriate dose for each patient individually, based on clinical evaluation and laboratory tests. Treatment usually starts with a small dose, which is increased every 2-4 weeks until the full dose, adjusted individually for each patient, is reached.
In the first weeks of treatment, it will be necessary to perform laboratory tests, which will allow your doctor to adjust the appropriate dose.
Typical dose ranges are presented in the table below. Smaller doses may be sufficient for:

• the elderly,
• patients with heart disease,
• patients with severe or prolonged hypothyroidism,
• patients with low body weight or giant goiter.

Administration in children and adolescents

In newborns and infants with congenital hypothyroidism, characterized by insufficient thyroid hormone production, for whom rapid supplementation is important, the recommended initial dose is 10 to 15 micrograms/kg body weight per day for the first 3 months.
Then, your doctor will adjust the dose individually, based on clinical evaluation and thyroid hormone and TSH levels.
Method of administration
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.
Infants should be given the entire daily dose of Euthyrox N at one time, at least half an hour before the first meal of the day. Before administration, the tablet should be crushed and mixed with a small amount of water. The resulting suspension should be given with an additional small amount of liquid.
A new suspension should be prepared each time before administration.
Duration of treatment
The duration of treatment may vary depending on the reason for taking Euthyrox N. Your doctor will discuss with you individually how long you should take the medicine.
Most patients need to take Euthyrox N for the rest of their lives.
In the event of a need to change the dose of the medicine, your doctor may recommend Euthyrox N with a different strength.

Overdose of Euthyrox N

In the event of taking a higher dose than recommended, the following symptoms may occur: rapid heartbeat, anxiety, agitation, or involuntary movements. In patients with neurological disorders, such as epilepsy, single seizures have been observed.
Overdose may cause hyperthyroidism and lead to symptoms of acute psychosis.
In such cases, you should consult your doctor.

Missed dose of Euthyrox N

You should not take a double dose to make up for a missed dose. The next day, you should take the usual dose of the medicine.
If you have any further doubts about taking this medicine, you should consult your doctor or pharmacist.

4. Possible side effects

Like all medicines, Euthyrox N can cause side effects, although not everybody gets them.
Euthyrox N is identical to the natural thyroid hormone. Therefore, if Euthyrox N is taken in the dose recommended by your doctor and if regular laboratory tests are performed, side effects should not occur.
You should stop taking the medicine and consult your doctor immediately if you experience sudden symptoms of hypersensitivity to the ingredients of Euthyrox N: facial swelling, tongue or throat swelling, difficulty swallowing, difficulty breathing (angioedema); respiratory reactions (progressive shortness of breath); skin reactions (rash, urticaria). The frequency of these side effects is unknown.
If you take a higher dose of Euthyrox N than recommended or if you have poor tolerance to the recommended dose (e.g., if the dose is increased too quickly), you may experience some of the following side effects: irregular or rapid heartbeat, palpitations, chest pain, headache, weakness or muscle cramps, hot flashes (feeling of heat and facial flushing), fever, vomiting, menstrual disorders, pseudo-tumor cerebri (increased intracranial pressure), tremors, restlessness, sleep disturbances, sweating, weight loss.
If you experience any of these symptoms, you should contact your doctor.
Your doctor may decide to stop treatment for a few days or reduce the daily dose until the symptoms disappear.

Reporting side effects

If you experience any side effects, including any not listed in this leaflet, you should inform your doctor or pharmacist. Side effects can be reported directly to the Department of Drug Safety Monitoring 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
Side effects can also be reported to the marketing authorization holder.
Reporting side effects will help to gather more information on the safety of the medicine.

5. How to store Euthyrox N

The medicine should be stored out of sight and reach of children.
Do not take Euthyrox N after the expiry date stated on the blister or carton after "EXP". The expiry date refers to the last day of the month.
Do not store above 25°C.
Store the blister in the outer packaging to protect from light.
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 needed. This will help protect the environment.

6. Contents of the packaging and other information

What Euthyrox N contains

• The active substance of Euthyrox N is sodium levothyroxine. Each tablet contains 25 micrograms, 50 micrograms, 75 micrograms, 125 micrograms, or 175 micrograms of sodium levothyroxine.
• The other ingredients are: cornstarch, citric acid, gelatin, sodium carboxymethylcellulose, magnesium stearate, and mannitol (E 421).

What Euthyrox N looks like and contents of the packaging

Euthyrox N tablets are white, round, flat, with a dividing line on both sides, with beveled edges, and an inscription on one side:
Euthyrox N 25: EM 25
Euthyrox N 50: EM 50
Euthyrox N 75: EM 75
Euthyrox N 125: EM 125
Euthyrox N 175: EM 175
The tablet can be divided into equal doses.
Euthyrox N is available in packs containing 50 or 100 tablets in a carton.
Not all pack sizes may be marketed.

Marketing authorization holder

Merck Sp. z o.o.
Al. Jerozolimskie 142B
02-305 Warsaw, Poland
tel.: +48 22 53 59 700
Logo of the marketing authorization 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
Date of last revision of the leaflet: