Letrox 25 mikrogramuv

Patient Information Leaflet: Letrox 25 micrograms

Letrox 25 micrograms,25 micrograms, tablets
Levothyroxine sodium

Read the leaflet carefully before taking the medicine, as it contains important information for the patient.

• Keep this leaflet, you may need to read it again.
• 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 those not listed in this leaflet, please inform your doctor or pharmacist. See section 4.

Table of Contents

• 1. What is Letrox 25 micrograms and what is it used for
• 2. Important information before taking Letrox 25 micrograms
• 3. How to take Letrox 25 micrograms
• 4. Possible side effects
• 5. How to store Letrox 25 micrograms
• 6. Contents of the pack and other information

1. What is Letrox 25 micrograms and what is it used for

Letrox 25 micrograms is a medicine containing the thyroid hormone levothyroxine as the active substance.
It has the same effect as the hormone produced naturally by the body.
The goal of treatment with Letrox 25 micrograms is to supplement thyroid hormone deficiency and/or alleviate thyroid dysfunction.
Letrox 25 micrograms is used:

• To supplement thyroid hormone deficiency in any form of hypothyroidism.
• To prevent the recurrence of goiter (enlargement of the thyroid gland) after surgical treatment in patients with normal thyroid function.
• To treat benign goiter in patients with normal thyroid function.
• As an adjunct in the treatment of hyperthyroidism in combination with thyroid inhibitors (drugs that inhibit thyroid function) after achieving normal thyroid function.
• In the treatment of malignant thyroid tumors, especially after thyroidectomy, to inhibit tumor growth and supplement thyroid hormone deficiency.

Letrox 25 micrograms is indicated for use in all age groups.

2. Important information before taking Letrox 25 micrograms

When not to take Letrox 25 micrograms

• If you are allergic to levothyroxine sodium or any of the other ingredients of this medicine (listed in section 6).
• If you have any of the following diseases or conditions:
• untreated hyperthyroidism
• untreated adrenal insufficiency
• untreated hypopituitarism, if it leads to adrenal insufficiency requiring treatment
• recent myocardial infarction
• acute myocarditis
• acute pericarditis (inflammation of the heart sac).

In case of pregnancy, do not take Letrox 25 micrograms at the same time as drugs that inhibit thyroid function (so-called antithyroid drugs) (see also section "Pregnancy, breastfeeding, and fertility").

Medical history of other diseases

Before starting treatment with Letrox 25 micrograms, your doctor should rule out or treat the following disorders or conditions:

• coronary heart disease
• chest pain with pressure (angina pectoris)
• high blood pressure (hypertension)
• hypopituitarism and/or adrenal insufficiency
• areas in the thyroid gland that produce thyroid hormones uncontrollably (autonomous nodule).

Warnings and precautions

Before starting to take Letrox 25 micrograms, discuss it with your doctor or pharmacist.

Special caution is required when taking Letrox 25 micrograms:

• in patients with a history of myocardial infarction, coronary heart disease, heart failure, or arrhythmias(tachycardia), myocarditiswithout acute course or in case of long-term hypothyroidism. In such cases, it is necessary to avoid too high a concentration of thyroid hormones in the blood. It is necessary to more frequently determine the concentration of thyroid hormones. If mild symptoms of hyperthyroidism associated with taking Letrox 25 micrograms occur, you should discuss this with your doctor (see section 4. "Possible side effects").
• if the patient has adrenal insufficiency.
• in patients with hypothyroidismcaused by hypopituitarism. If there is concomitant adrenal insufficiency, the doctor should first start its treatment (hydrocortisone therapy). Without proper treatment, acute adrenal insufficiency (Addison's crisis) may occur.
• if there is a suspicion of thyroid areas producing hormones uncontrollably. This should be checked by performing additional thyroid function tests before starting treatment.
• in postmenopausal womenwith an increased risk of bone loss (osteoporosis). The attending physician should more frequently monitor thyroid function to avoid too high concentrations of thyroid hormone in the blood serum and ensure the use of the smallest effective dose of the medicine.
• in patients with diabetes. For further information, see the section "Letrox 25 micrograms and other medicines".
• in patients taking anticoagulant drugs(e.g., dicumarol) and drugs affecting the thyroid gland (e.g., amiodarone, tyrosine kinase inhibitors [drugs used in cancer treatment], salicylates, and high doses of furosemide). For further information, see the section "Letrox 25 micrograms and other medicines".
• if, for example, a dialyzed patientis being treated with the substance sevelamer due to high phosphate levels in the blood, the attending physician will likely consider monitoring certain blood parameters to assess the effectiveness of levothyroxine treatment (see also "Letrox 25 micrograms and other medicines").
• if the patient has a history of epilepsy, due to the increased risk of seizures.
• if the patient experiences an allergic reaction(see section 4. "Possible side effects"). You should immediatelycontact your doctor or healthcare provider or immediatelygo to the emergency department of the nearest hospital.
• if the patient is to undergo laboratory tests to check thyroid hormone levels, the patient should inform the doctor or laboratory staff about current or recent intake of 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. The doctor may recommend that the patient stop taking biotin before undergoing laboratory tests. It should also be remembered that other products taken by the patient, 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").

Misuse

Letrox 25 micrograms should not be used to reduce weight. In patients with normal thyroid hormone levels in the blood, taking additional thyroid hormones will not lead to weight loss. Taking excessive amounts of thyroid hormones or increasing the dose without special doctor's recommendations can cause serious, even life-threatening side effects, especially in combination with other weight-reducing drugs.

Change of treatment

In case of a need to switch to another levothyroxine-containing drug, a disruption of thyroid function balance may occur. If you have any questions about switching drugs, discuss it with your doctor. Patients should be closely monitored (clinically and biologically) during the transition period. If any side effects occur, inform your doctor, as this may indicate the need to adjust the dose (increase or decrease the dose).

Elderly patients

In elderly patients (especially those with heart problems), the dose should be increased with caution, and patients should undergo more frequent medical check-ups.

Children and adolescents

When starting levothyroxine treatment 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 (see section 4. "Possible side effects").

Letrox 25 micrograms and other medicines

Tell your doctor or pharmacist about all medicines you are taking now or have recently taken, as well as any medicines you plan to take.

Letrox 25 micrograms affects the action of the following medicinal substances and groups of medicines:

• Antidiabetic medicines (drugs that lower blood sugar levels, such as metformin, glimepiride, glibenclamide, and insulin):In diabetic patients, blood sugar levels should be regularly monitored, especially at the beginning and after the end of thyroid hormone treatment. If necessary, the doctor may adjust the dose of the antidiabetic medicine, as levothyroxine may weaken its effect.
• Coumarin derivatives (anticoagulant drugs):

When taking Letrox 25 micrograms at the same time as coumarin derivatives (e.g., dicumarol), blood clotting parameters should be regularly monitored. If necessary, the doctor may reduce the dose of the anticoagulant drug, as levothyroxine may enhance its effect.

The action of Letrox 25 micrograms may be affected by the following medicines:

• Ion exchange resins:Drugs used to reduce blood fat levels (e.g., cholestyramine, colestyramine) or reduce high potassium levels in the blood (calcium or sodium polystyrene sulfonate) should be taken 4 to 5 hours after taking Letrox 25 micrograms. Otherwise, these drugs may inhibit the absorption of levothyroxine from the intestines and thus reduce its effectiveness.
• Proton pump inhibitors:Proton pump inhibitors (such as omeprazole, esomeprazole, pantoprazole, rabeprazole, and lansoprazole) used to reduce stomach acid production may inhibit the absorption of levothyroxine from the intestines and thus reduce its effectiveness. If the patient is taking levothyroxine during treatment with proton pump inhibitors, the doctor should monitor thyroid function and adjust the dose of Letrox 25 micrograms if necessary.
• Sevelamer and lanthanum carbonate:Sevelamer and lanthanum carbonate (drugs used to reduce elevated phosphate levels in the blood of dialyzed patients) may reduce the absorption and effectiveness of levothyroxine. The attending physician will perform more frequent monitoring of thyroid function (see also "Warnings and precautions").
• Bile acid sequestrants:Colesevelam (a drug that lowers cholesterol levels in the blood) binds to levothyroxine, thereby reducing its absorption from the intestine. Therefore, Letrox 25 micrograms should be taken 4 hours before taking colesevelam.
• Drugs that neutralize stomach acid containing aluminum, drugs containing iron, drugs containing calcium:Letrox 25 micrograms should be taken at least 2 hours before taking stomach acid-neutralizing drugs containing aluminum (antacids, sucralfate), iron-containing drugs, or calcium-containing drugs. Otherwise, these drugs may reduce the absorption of levothyroxine from the intestines and thus reduce its effectiveness.
• Propylthiouracil, glucocorticoids, beta-adrenergic blockers (especially propranolol):Propylthiouracil (a drug used in hyperthyroidism), glucocorticoids (adrenal cortex hormones, "cortisone"), and beta-adrenergic blockers (drugs that slow down heart rate and lower blood pressure) inhibit the conversion of levothyroxine to its more active form, liotyronine, and may thus reduce the effectiveness of Letrox 25 micrograms.
• Amiodarone and iodine-containing contrast agents:Amiodarone (a drug used in the treatment of arrhythmias) and iodine-containing contrast agents (mainly drugs used in X-ray diagnostics) may, due to their high iodine content, cause both hypothyroidism and hyperthyroidism. Particular attention should be paid to patients with nodular goiter, in whom there may be unrecognized autonomy of the thyroid gland (autonomy) releasing hormones uncontrollably. Amiodarone inhibits the conversion of levothyroxine to its more active form, liotyronine, and thus affects the action of Letrox 25 micrograms. If necessary, the attending physician will adjust the dose of Letrox 25 micrograms.
• The following medicines may affect the action of Letrox 25 micrograms: Salicylates, especially doses above 2 g per day (antipyretic and analgesic drugs), Dicumarol(anticoagulant drug), Furosemide(diuretic drug) in high doses (250 mg), Clofibrate(drug that lowers elevated blood fat levels)
• Contraceptives and hormone replacement therapy:Contraceptives containing estrogens ("birth control pills") and postmenopausal hormone replacement therapy may increase the need for levothyroxine.
• Sertraline, chloroquine/proguanil:Sertraline (a drug used in the treatment of depression) and chloroquine and proguanil (drugs used in the treatment of malaria and rheumatoid arthritis) reduce the effectiveness of levothyroxine.
• Rifampicin, carbamazepine, phenytoin, barbiturates, products containing St. John's wort:Rifampicin (an antibiotic), carbamazepine (used in the treatment of epilepsy), phenytoin (used in the treatment of epilepsy and arrhythmias), barbiturates (used in epileptic seizures, for anesthesia; some sleeping pills), and products containing St. John's wort (a herbal medicinal product) may weaken the effect of levothyroxine.
• Protease inhibitors (drugs used in the treatment of HIV and hepatitis C virus infections): The doctor should carefully monitor the symptoms of the disease and thyroid function in patients taking levothyroxine and protease inhibitors (lopinavir, ritonavir) at the same time. During concurrent use of levothyroxine with lopinavir and/or ritonavir, its effectiveness may be reduced.
• Tyrosine kinase inhibitors (drugs used in cancer treatment):The doctor should carefully monitor clinical symptoms and thyroid function in patients taking levothyroxine and tyrosine kinase inhibitors (e.g., imatinib, sunitinib, sorafenib, motesanib) at the same time. The effectiveness of levothyroxine may be reduced; if necessary, the doctor will adjust the dose of levothyroxine.
• Semaglutide:If the patient is taking levothyroxine at the same time as semaglutide (an antidiabetic drug), it may affect the level of levothyroxine, and the doctor may recommend monitoring thyroid hormone levels and adjusting the dose of Letrox 25 micrograms.
• Orlistat:Orlistat (used in the treatment of obesity) may reduce the absorption of levothyroxine.
• Biotin (also known as vitamin H, vitamin B7, or vitamin B8):If the patient is currently taking or has recently taken biotin, they must inform their doctor or laboratory staff if they are to undergo thyroid hormone level tests. Biotin may affect laboratory test results (see "Warnings and precautions").

Letrox 25 micrograms with food and drink

Letrox 25 micrograms should not be taken with a meal, especially if the diet is rich in calcium (e.g., milk and dairy products), as this may significantly reduce the absorption of levothyroxine.
In the case of a diet containing soy, the doctor will more frequently monitor thyroid hormone levels in the blood. During such a diet and after its completion, it may be necessary to adjust the dose of Letrox 25 micrograms by the doctor (usually higher doses are required), as soy products disrupt the absorption of levothyroxine in the intestines, thereby reducing its effectiveness.
Letrox 25 micrograms should not be taken with coffee, as this may reduce the absorption of levothyroxine from the intestines and thus reduce its effectiveness. After taking Letrox 25 micrograms, you should wait at least half an hour to an hour before drinking coffee. It is recommended that patients taking levothyroxine do not change their coffee drinking habits without checking and monitoring their levothyroxine levels by the attending physician.

Pregnancy, breastfeeding, and fertility

If you are pregnant or breastfeeding, think you may be pregnant, or plan to have a child, ask your doctor or pharmacist for advice before taking this medicine.
Proper treatment with thyroid hormones is particularly important for the health of the mother and fetus during pregnancy and breastfeeding. Therefore, treatment should be continued uninterrupted under the supervision of the attending physician. Despite the widespread use of levothyroxine during pregnancy, its negative impact on the course of pregnancy or the health of the fetus or newborn remains unknown to date.
Thyroid function should be monitored both during and after pregnancy. The doctor may adjust the dose, as the need for thyroid hormone may increase during pregnancy due to increased estrogen levels in the blood (female sex hormone).
During pregnancy, do not take Letrox 25 micrograms at the same time as drugs that inhibit thyroid function (thyroid inhibitors), as this may require the use of higher doses of thyroid inhibitors. Thyroid inhibitors (unlike levothyroxine) can pass into the fetus's bloodstream through the placenta and cause hypothyroidism in the unborn child. In case of hyperthyroidism during pregnancy, the doctor should use only small doses of thyroid inhibitors.
If you are breastfeeding, you should continue taking levothyroxine as recommended by your doctor. Even when taking high doses of levothyroxine during breastfeeding, the amount of levothyroxine that passes into breast milk is very small and is therefore harmless.
Hypothyroidism or hyperthyroidism may affect fertility.
During treatment of patients with hypothyroidism, the dose of Letrox 25 micrograms should be adjusted based on laboratory test results, as an insufficient dose may not improve hypothyroidism, and overdose may lead to hyperthyroidism.

Driving and using machines

No studies have been conducted on the effect of Letrox 25 micrograms on the ability to drive and use machines.

Letrox 25 micrograms 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 Letrox 25 micrograms

This medicine should always be taken exactly as directed by your doctor. If you are unsure, ask your doctor or pharmacist.
The doctor will determine the daily dose for each patient based on control tests.

Dosage

Tablets with different active substance content (25-150 micrograms of levothyroxine sodium) are available for individual treatment, which means that most patients will take one tablet per day.

Depending on the symptoms, the doctor will adjust the dose according to the following guidelines:

• In the treatment of hypothyroidism, the initial dose for adults is 25-50 micrograms of levothyroxine sodium per day. The doctor may recommend increasing the dose by 25-50 micrograms of levothyroxine sodium at 2-4 week intervals until a daily dose of 100-200 micrograms of levothyroxine sodium is reached.
• To prevent the recurrence of goiter after its removal and in the treatment of benign goiter, the daily dose is 75-200 micrograms of levothyroxine sodium.
• As an adjunct in the treatment of hyperthyroidism in combination with thyroid inhibitors, the daily dose is 50-100 micrograms of levothyroxine sodium.
• After thyroidectomy due to malignant thyroid tumors, the daily dose is 150-300 micrograms of levothyroxine sodium.

A smaller dose of thyroid hormone may also be sufficient.

Use in children and adolescents

The maintenance dose during long-term treatment of congenital or acquired hypothyroidism is usually 100-150 micrograms of levothyroxine sodium per m² of body surface area per day.
In the case of newborns and infants with congenital hypothyroidism, it is particularly important to start treatment as soon as possible to achieve normal mental and physical development. The recommended initial dose is 10-15 micrograms of levothyroxine sodium per kg of body weight per day for the first 3 months. Then, the doctor will adjust the daily dose individually based on the results of clinical examination (in particular, based on thyroid hormone levels in the blood).
In children with acquired hypothyroidism, the recommended initial dose is 12.5-50 micrograms of levothyroxine sodium per day. The doctor will gradually increase the daily dose at 2-4 week intervals until the total replacement dose is reached. To this end, the doctor will particularly monitor thyroid hormone levels in the blood.

Elderly patients, patients with coronary heart disease, patients with hypothyroidism

In elderly patients, patients with coronary heart disease, and patients with severe or long-term hypothyroidism, treatment with thyroid hormones should be started with caution (small initial dose, which should then be slowly increased over a long period, with frequent monitoring of thyroid hormone levels).

Patients with low body weight and patients with large goiter

Experience indicates that smaller doses are also sufficient in patients with low body weight and in patients with large goiter.

Method of administration

Take the entire daily dose in the morning, with a large amount of liquid, preferably a glass of water, on an empty stomach, at least half an hour before breakfast. The active substance is better absorbed on an empty stomach than before or after a meal.
Children should take the entire daily dose at least half an hour before the first meal. The tablets can also be dissolved in a suitable amount of water (10-15 mL), and the resulting suspension (the tablets must be dissolved just before administration!) should be given with a small additional amount of liquid (5-10 mL).

Duration of treatment

Letrox 25 micrograms is usually taken for life in hypothyroidism and after thyroidectomy due to malignant thyroid tumors, and in the case of benign goiter and prevention of goiter recurrence, treatment lasts for several months or years, or even for life. In supportive therapy for hyperthyroidism, Letrox 25 micrograms should be taken for as long as thyroid inhibitors (drugs that inhibit thyroid function) are taken. Treatment of benign goiter with normal thyroid function should last from 6 months to 2 years. If treatment with Letrox 25 micrograms does not produce the expected effect during this time, the doctor will consider other treatment options.

Overdose of Letrox 25 micrograms

Symptoms of overdose have been described in section 4. "Possible side effects". If such symptoms occur, you should see a doctor.

Missed dose of Letrox 25 micrograms

If you ever take too little of the medicine or miss a dose, do not take a double dose to make up for the missed dose. Continue taking the medicine as directed by your doctor.

Stopping treatment with Letrox 25 micrograms

To achieve the desired therapeutic effect, Letrox 25 micrograms should be taken regularly in the dose prescribed by your doctor. Under no circumstances should the treatment be changed, interrupted, or discontinued prematurely without consulting your doctor, as the symptoms may recur.
If you have any further questions about the use of this medicine, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, Letrox 25 micrograms can cause side effects, although not everybody gets them.

Hypersensitivity to the active substance or any of the other ingredients of Letrox 25 micrograms

In case of hypersensitivity to levothyroxine or any of the other ingredients of Letrox 25 micrograms, allergic skin reactionsand allergic reactions related to the respiratory system(either immediately or within a few days of administration), which can be life-threatening, may occur. These symptoms may include rash, itching, difficulty breathing, shortness of breath, swelling of the face, lips, throat, or tongue. You should immediatelycontact your doctor or healthcare provider or immediatelygo to the emergency department of the nearest hospital.

Intolerance to the prescribed dose, overdose

In individual cases, when the prescribed dose is not tolerated or the medicine is overdosed, especially when the dose is increased too quickly at the beginning of treatment, typical symptoms of hyperthyroidism may occur.
Very common:may affect more than 1 in 10 patients

• Palpitations
• Insomnia
• Headache

Common:may affect up to 1 in 10 patients

• Fast heart rate (tachycardia)
• Nervousness

Rare:may affect up to 1 in 1,000 patients

• Increased intracranial pressure (especially in children)

Frequency not known:cannot be estimated from the available data

• Hypersensitivity
• Arrhythmias
• Chest pain with a feeling of pressure (angina pectoris)
• Skin allergic reactions (e.g., angioedema [difficulty breathing or swelling of the face, lips, throat, or tongue], rash, urticaria)
• Anxiety
• Muscle weakness, muscle cramps
• Osteoporosis during long-term use of high doses of levothyroxine, especially in postmenopausal women, mainly those taking the medicine for a long time
• Feeling of heat, intolerance to high temperature, circulatory collapse in premature infants with low birth weight (see section 2. "Warnings and precautions")
• Menstrual disorders
• Diarrhea
• Vomiting
• Nausea
• Weight loss
• Tremors
• Excessive sweating
• Fever

Tell your doctor about any side effects. They will decide whether to reduce the daily dose or stop taking the medicine for a few days. As soon as the side effects disappear, the doctor may resume treatment, carefully selecting the dose.

Reporting side effects

If you experience any side effects, including those not listed in this leaflet, please inform your doctor or pharmacist or nurse. 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
Phone: +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, you can help provide more information on the safety of this medicine.

5. How to store Letrox 25 micrograms

Keep the medicine out of the sight and reach of children.
Do not use this medicine after the expiry date stated on the blister pack and carton after "EXP". The expiry date refers to the last day of the month.
Store in a temperature below 30°C.
Store in the original blister pack to protect from light.
Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines that are no longer needed. This will help protect the environment.

6. Contents of the pack and other information

What Letrox 25 micrograms contains

The active substance of the medicine is levothyroxine sodium.
Each tablet contains 25 micrograms of levothyroxine sodium.
The other ingredients are:
Cysteine hydrochloride monohydrate (partially present in the tablet as cystine), microcrystalline cellulose, cornstarch, pregelatinized starch, light magnesium oxide, talc.

What Letrox 25 micrograms looks like and contents of the pack

Letrox 25 micrograms is a white to beige, round, slightly convex tablet.
The pack contains 28, 50, or 100 tablets.
Not all pack sizes may be marketed.

Marketing authorization holder and manufacturer

BERLIN-CHEMIE AG
Glienicker Weg 125
12489 Berlin, Germany
For more information about this medicine, please contact the local representative of the marketing authorization holder:
Berlin-Chemie/Menarini Polska Sp. z o.o.
Phone: +48 22 566 21 00
Fax: +48 22 566 21 01

This medicine is authorized in the Member States of the European Economic Area under the following names:

Bulgaria: L-Thyroxin 25 Berlin-Chemie
Czech Republic: Letrox
Germany: L-Thyroxin BC 25 Mikrogramm
Latvia: Levothyroxine sodium Berlin-Chemie 25 mikrogrami tabletes
Lithuania: L-Thyroxin Berlin-Chemie 25
Poland: Letrox 25 micrograms
Slovakia: L-Thyroxin 25 Berlin-Chemie

Date of last revision of the leaflet: 11/2023