Euthirox N 75

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 doubts, you should consult a doctor or pharmacist.
• This medicine has been prescribed specifically for you. Do not pass it on to others. The medicine may harm another person, even if their symptoms are the same as yours.
• If the patient experiences any side effects, including any side effects not listed in this leaflet, they should inform their doctor or pharmacist. See section 4.

Table of contents of the leaflet

• 1. What is Euthyrox N and what is it 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 is Euthyrox N and what is it 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 drugs due to excessive thyroid hormone production.

2. Important information before taking Euthyrox N

When not to take Euthyrox N

• if the patient is allergic to the active substance or any of the other ingredients of this medicine (listed in section 6.),
• if the patient has untreated hypopituitarism or if thyroid hormones are produced in excess (untreated hyperthyroidism),
• if the patient has adrenal insufficiency and is not receiving appropriate replacement therapy,
• if the patient has recently had a heart attack, myocarditis, or acute pancreatitis. Euthyrox N should not be taken at the same time as antithyroid drugs if the patient is pregnant (see "Pregnancy and breastfeeding" below).

Warnings and precautions

Before starting to take this medicine, the patient should inform their doctor about the following diseases:

• insufficient blood flow in the coronary arteries (angina pectoris),
• heart failure,
• rapid and irregular heart rhythm,
• high blood pressure,
• arteriosclerosis. 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. In case of doubts about whether the patient has any of the above diseases or if they are not being treated, the patient should consult a doctor.

Before starting to take Euthyrox N, the patient should tell their doctor if they have adrenal insufficiency.
The doctor will perform the necessary tests to determine if the patient has 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, blood pressure should be regularly monitored, as a sudden drop in blood pressure (so-called circulatory collapse) may occur.
In the event of a change of medicine to another levothyroxine-containing medicine, a disruption of thyroid hormone balance may occur. The patient should consult their doctor if they have any questions about changing medicines. During the transition period, close monitoring of clinical and biochemical parameters is necessary. The patient should inform their doctor if they 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 lead to weight loss if thyroid hormones are maintained at the proper level. Increasing the dose of the medicine without consulting a doctor may lead to serious and life-threatening side effects. The patient should not take high doses of levothyroxine in combination with other weight loss medicines, such as amfepramone, cactus, and phenylpropanolamine, due to the possible increased risk of serious and life-threatening side effects.
The patient should talk to their doctor:

• if the patient is in menopause or postmenopause; the doctor may then recommend more frequent, regular monitoring of thyroid function due to the risk of osteoporosis;
• in case of diabetes or taking anticoagulant medicines (medicines that reduce blood clotting);
• when starting to take orlistat or stopping its use or changing orlistat treatment (a medicine used to treat obesity); more frequent monitoring and dose adjustment may be necessary;
• in case of psychotic disorders, the doctor may recommend more frequent monitoring and dose adjustment;
• if the patient is to undergo laboratory tests to check thyroid hormone levels, they should inform their doctor or laboratory staff about current or recent biotin use (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 decreased due to biotin use. The doctor may recommend that the patient stop taking biotin before undergoing laboratory tests. The patient should also remember that other products they are taking, such as multivitamins 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 their doctor or laboratory staff (see "Warnings and precautions").

Euthyrox N and other medicines

The patient should tell their doctor about all medicines they are currently taking or have recently taken, as well as any medicines they plan to take.
In case of taking any of the following medicines, the patient should inform their doctor, as Euthyrox N may affect the action of these medicines:

• antidiabetic medicines (medicines that lower blood sugar levels): Euthyrox N may weaken the effect of antidiabetic medicines, 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 change the dose of antidiabetic medicine;
• anticoagulant medicines (coumarin derivatives): Euthyrox N may enhance the effect of these medicines, 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 change the dose of anticoagulant medicine.

In case of taking any of the following medicines at the same time as Euthyrox N, the patient should strictly follow the doctor's recommendations regarding the time intervals between taking the individual medicines:

• bile acid-binding resins and cholesterol-lowering medicines (cholestyramine or colestipol): Euthyrox N should be taken 4 to 5 hours before taking these medicines, as they may inhibit the absorption of Euthyrox N from the gut;
• antacids (used to relieve heartburn), sucralfate (used to treat stomach and intestinal ulcers), other medicines containing aluminum, medicines containing iron, medicines containing calcium: Euthyrox N should be taken at least 2 hours before taking these medicines, as otherwise, they may weaken the effect of Euthyrox N.

In case of taking any of the following medicines, the patient should inform their doctor, as these medicines may weaken the effect of Euthyrox N:

• propylthiouracil (an antithyroid medicine),
• glucocorticoids (anti-allergic and anti-inflammatory medicines),
• beta-adrenergic blockers (medicines that lower blood pressure, also used to treat heart diseases),
• sertraline (an antidepressant medicine),
• sevelamer (a medicine that lowers phosphate levels, used in patients with chronic kidney failure),
• tyrosine kinase inhibitors (medicines used to treat cancer),
• chloroquine or proguanil (medicines used to treat or prevent malaria),
• medicines that activate certain liver enzymes, such as barbiturates (sedatives, sleeping pills), carbamazepine (an antiepileptic medicine also used to alleviate certain types of pain and control mood disorders), medicines containing St. John's Wort (some herbal medicines),
• medicines containing estrogens, used in hormone replacement therapy during menopause and postmenopause or to prevent pregnancy,
• proton pump inhibitors (such as omeprazol, esomeprazol, pantoprazol, rabeprazol, and lansoprazol) used to reduce stomach acid production, which may weaken the absorption of levothyroxine from the gut and make it less effective. If the patient is taking levothyroxine during treatment with proton pump inhibitors, the doctor should monitor thyroid function and adjust the dose of Euthyrox N if necessary,
• orlistat (a medicine used to treat obesity).

In case of taking any of the following medicines, the patient should inform their doctor, as these medicines may enhance the effect of Euthyrox N:

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

In case of taking orlistat, the patient should inform their doctor. Taking Euthyrox N and orlistat at the same time may cause hypothyroidism and (or) worsen the control of hypothyroidism.
If the patient is taking protease inhibitors (medicines used to treat HIV infections, such as ritonavir, indinavir, lopinavir) or phenytoin (an antiepileptic medicine), which may affect the action of Euthyrox N, they should inform their doctor.
In this case, it may be necessary to perform a thyroid hormone test and adjust the dose of the medicine.
In case of taking amiodarone (a medicine used to treat heart rhythm disorders), the patient should inform their doctor, as this medicine may affect thyroid function.
The patient should inform their doctor about taking Euthyrox N if they need to undergo a diagnostic test involving the administration of a contrast agent containing iodine, as this test is associated with the administration of an injection that affects thyroid function.
If the patient is currently taking or has recently taken biotin, they must inform their doctor or laboratory staff if they 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 the patient's diet includes soy products, they should inform their doctor, especially if they change the amount of these products they 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 the patient is pregnant or breastfeeding, thinks they may be pregnant, or plans to have a child, they should consult their doctor or pharmacist before taking this medicine.
During pregnancy, the patient should continue to take Euthyrox N under medical supervision, as it may be necessary to adjust the dose of the medicine.
If Euthyrox N was taken at the same time as an antithyroid medicine to treat excessive thyroid hormone production, the doctor will recommend stopping Euthyrox N after becoming pregnant.
During pregnancy, the patient should not take antithyroid medicines at the same time.
During pregnancy, the patient should not undergo diagnostic tests that involve inhibiting thyroid function.
During breastfeeding, the patient should continue to take Euthyrox N as recommended by their doctor. The amount 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 recommended by the doctor. In case of doubts, the patient should consult their doctor or pharmacist.
The doctor will determine the appropriate dose for each patient 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, laboratory tests will be necessary to allow the 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.

Use in children and adolescents

In newborns and infants with congenital hypothyroidism, where it is essential to quickly supplement them, the recommended initial dose is 10 to 15 micrograms/kg body weight per day for the first 3 months. Then, the 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 once, 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 of the medicine should be prepared each time before administration.
Duration of treatment
The duration of treatment may vary depending on the reason for taking Euthyrox N. The doctor will discuss with each patient how long they need to take the medicine.
Most patients need to take Euthyrox N for their entire lives.
In case of a need to change the dose of the medicine, the doctor may recommend Euthyrox N with a different strength.

Taking a higher dose of Euthyrox N than recommended

In case of taking a higher dose of Euthyrox N than recommended, the following symptoms may occur: rapid heartbeat, restlessness, excitement, 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, the patient should consult a doctor.

Missing a dose of Euthyrox N

The patient should not take a double dose to make up for a missed dose. The next day, they should take their usual dose of the medicine.
In case of any further doubts about taking this medicine, the patient should consult their 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 the doctor and if regular laboratory tests are performed, side effects should not occur.
The patient should stop taking the medicine and consult their doctor immediately if they experience sudden symptoms of hypersensitivity to the ingredients of Euthyrox N: facial swelling, tongue or throat swelling, difficulty swallowing, difficulty breathing (angioedema); respiratory reactions (increasing shortness of breath); skin reactions (rash, urticaria). The frequency of these side effects is unknown.
In case of taking a higher dose of Euthyrox N than recommended or in case of poor tolerance to the recommended dose (e.g., rapid dose increase), some of the following side effects may occur: 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, diarrhea.
In case of experiencing any of the above symptoms, the patient should contact their doctor.

Reporting side effects

If the patient experiences any side effects, including any side effects not listed in this leaflet, they should inform their 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.
By reporting side effects, it is possible 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.
Euthyrox N should not be taken after the expiry date stated on the blister or carton after "EXP". The expiry date refers to the last day of the month.
The medicine should not be stored at temperatures above 25°C.
To protect from light, the blister should be stored in the outer packaging.
Medicines should not be disposed of via wastewater or household waste. The patient should ask their 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 carmellose, magnesium stearate, and mannitol (E 421).

What Euthyrox N looks like and contents of the pack

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: