Althixin

Leaflet attached to the packaging: information for the user

Althyxin, 25 micrograms, tablets
Althyxin, 50 micrograms, tablets
Althyxin, 75 micrograms, tablets
Althyxin, 100 micrograms, tablets
Althyxin, 125 micrograms, tablets
Althyxin, 150 micrograms, tablets
Althyxin, 175 micrograms, tablets
Althyxin, 200 micrograms, tablets
Levothyroxine sodium

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

• Keep this leaflet, so you can read it again if you need to.
• If you have any doubts, consult your 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.
• If the patient experiences any side effects, including any side effects not listed in this leaflet, they should tell their doctor or pharmacist. See section 4.

Table of contents of the leaflet

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

1. What is Althyxin and what is it used for

The active substance of Althyxin is levothyroxine, a synthetic thyroid hormone used to treat thyroid function disorders and diseases. It has the same effect as the thyroid hormone that occurs naturally in the body.
Althyxin is used:

• to treat mild goiter in patients with normal thyroid function,
• to prevent goiter recurrence 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. Althyxin is also used to balance thyroid hormone levels when thyroid hormone overproduction is treated with antithyroid drugs. Althyxin 100 micrograms, 150 micrograms, and 200 micrograms may also be used in tests assessing thyroid function.

2. Important information before taking Althyxin

When not to take Althyxin:

• if the patient is allergic (hypersensitive) to the active substance or any of the other ingredients of Althyxin (listed in section 6),
• if the patient has untreated pituitary gland dysfunction or if thyroid hormones are overproduced (hyperthyroidism),
• in case of adrenal insufficiency (adrenal cortex insufficiency) and if the patient does not have adequate replacement therapy,

and

• in case of acute heart disease (myocardial infarction or myocarditis).

During pregnancy, do not take Althyxin at the same time as antithyroid drugs (thyrostatics) (see "Pregnancy and breastfeeding").

Warnings and precautions

Before starting Althyxin, discuss with your doctor or pharmacist if you have any of the following heart diseases:

• insufficient blood flow in the coronary arteries (angina pectoris),
• heart failure,
• rapid or irregular heart rhythm,
• high blood pressure (hypertension),
• fatty deposits in the arteries (arteriosclerosis).

It is necessary to treat these disorders before starting Althyxin or performing a thyroid function test. During Althyxin treatment, regular monitoring of thyroid hormone levels is necessary. If you have any doubts about whether you have any of these diseases or if they are not treated, consult your doctor.
If you have adrenal insufficiency (adrenal cortex insufficiency) before taking Althyxin, consult your doctor. The doctor will perform the necessary tests to determine if you have adrenal, pituitary, or thyroid dysfunction with uncontrolled thyroid hormone overproduction (autonomous thyroid function), as in such cases, appropriate treatment or a thyroid function test is necessary before starting Althyxin.
Discuss with your doctor:

• if you are in menopause or postmenopause; your doctor may then recommend regular thyroid function monitoring due to the risk of osteoporosis;
• if you are switching from one levothyroxine-containing medicine to another. The effect of these medicines may differ slightly, so more frequent monitoring and dose adjustment may be necessary;
• before starting orlistat (a medicine used to treat obesity) and if you stop taking it or change your orlistat treatment, as in these cases, more frequent monitoring and dose adjustment may be necessary;
• in case of psychotic symptoms, as more frequent monitoring and dose adjustment may be necessary;
• if you are to undergo laboratory tests to check your thyroid hormone levels, inform your doctor or laboratory staff if you are taking or have recently taken biotin (also known as vitamin H, vitamin B7, or vitamin B8). Biotin may affect laboratory test results (see "Warnings and precautions").

Althyxin and other medicines

Tell your doctor or pharmacist about all medicines you are taking or have recently taken, as Althyxin may affect the action of the following medicines:

• Antidiabetic medicines (medicines that lower blood sugar levels): Althyxin may reduce the effect of the medicine that lowers blood sugar levels, which may require additional blood sugar level checks, especially at the beginning of Althyxin treatment. During Althyxin treatment, it may be necessary to adjust the dose of the antidiabetic medicine.

and

• Anticoagulants (medicines used to prevent blood clots): Althyxin may increase the effect of these medicines, which may increase the risk of bleeding, especially in elderly patients. Therefore, periodic monitoring of blood coagulation parameters may be necessary before starting treatment and during Althyxin treatment. During Althyxin treatment, it may be necessary to adjust the dose of the anticoagulant medicine.

Follow the recommendations for time intervals between taking this medicine and taking any of the following medicines.

• Bile acid sequestrants and cholesterol-lowering medicines (e.g., cholestyramine or colestipol): Take Althyxin 4 to 5 hours before taking these medicines, as they may inhibit Althyxin absorption from the gut.
• Antacids (used to relieve indigestion), sucralfate (used to treat stomach or duodenal ulcers), other medicines containing aluminum, iron-containing medicines, or calcium-containing medicines: Take Althyxin at least 2 hours before taking these medicines, as they may otherwise reduce the effect of Althyxin.

Discuss with your doctor or pharmacist if you are taking or have recently taken any of the following medicines, as they may reduce the effect of Althyxin:

• Propylthiouracil (an antithyroid medicine),
• Corticosteroids (anti-allergic and anti-inflammatory medicines),
• Beta-adrenergic blockers (medicines that lower blood pressure and are also used to treat heart diseases),
• Sertraline (an antidepressant),
• Chloroquine or proguanil (medicines used to prevent or treat malaria),
• Medicines that stimulate certain liver enzymes, such as barbiturates (sedatives, sleeping pills), carbamazepine (an antiepileptic medicine also used for certain types of pain and depressive disorders), or medicines containing St. John's Wort (some herbal medicines),
• Estrogen-containing medicines used for hormone replacement therapy during menopause and postmenopause or to prevent pregnancy,
• Sevelamer (a phosphate binder used in patients with chronic kidney failure),
• Tyrosine kinase inhibitors (anticancer and anti-inflammatory medicines),
• Orlistat (a medicine used to treat obesity),
• Proton pump inhibitors (such as omeprazol, esomeprazol, pantoprazol, rabeprazol, and lansoprazol) used to reduce stomach acid production, which may reduce levothyroxine absorption 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 Althyxin dose if necessary.

Discuss with your doctor or pharmacist if you are taking or have recently taken any of the following medicines, as they may enhance the effect of Althyxin:

• Salicylates (pain-relieving and antipyretic medicines),
• Dicumarol (a medicine that reduces blood coagulation),
• Furosemide in high doses of 250 mg or more (a diuretic),
• Clofibrate (a medicine that lowers blood lipid levels).

Discuss with your doctor or pharmacist if you are taking or have recently taken any of the following medicines, as they may affect the action of Althyxin:

• Protease inhibitors (used to treat HIV and chronic hepatitis C, e.g., ritonavir, indinavir, lopinavir), phenytoin (an antiepileptic medicine).

If you are taking biotin, you must inform your doctor or laboratory staff if you are to undergo thyroid hormone level tests. Biotin may affect laboratory test results (see "Warnings and precautions").
Regular monitoring of thyroid hormone levels and adjustment of the Althyxin dose may be necessary.
Thyroid function disorders may occur if it is necessary to switch to another levothyroxine-containing medicine. If you have any questions about switching medicines, consult your doctor. Close monitoring (clinical and biological) is necessary during the transition period. Inform your doctor if you experience any side effects, as this may indicate that the dose needs to be increased or decreased.
Inform your doctor if you are taking amiodarone (a medicine used to treat irregular heart rhythm), as it may affect thyroid function.
Tell your doctor if you are taking Althyxin and need to undergo an X-ray or other diagnostic test with a contrast agent containing iodine, as this test involves an injection that affects thyroid function.
Inform your doctor or pharmacist if you are taking or have recently taken other medicines, including those available without a prescription.
Thyroid hormones are not suitable for weight loss. Taking thyroid hormones will not lead to weight loss if thyroid hormone levels are normal. Increasing the dose without a doctor's recommendation may lead to severe and life-threatening side effects, especially when taken with other weight-loss medicines.

Using Althyxin with food and drink

Tell your doctor if your diet includes soy products, especially if you change the proportion of these products in your diet. Soy products may reduce Althyxin absorption from the gut, which may require a change in Althyxin dosing.

Pregnancy and breastfeeding

If you are pregnant, continue taking Althyxin, but discuss it with your doctor, as a dose adjustment may be necessary.
If you are taking Althyxin and antithyroid medicines for hyperthyroidism, your doctor will recommend stopping Althyxin at the beginning of pregnancy.
If you are breastfeeding, you can continue taking Althyxin as directed by your doctor. The amount of medicine that passes into breast milk is small and does not affect the baby.

Driving and using machines

No studies have been conducted to assess the impact on driving ability and machine operation. It is not expected that Althyxin will affect driving ability and machine operation, as the levothyroxine in this medicine is identical to the thyroid hormone that occurs naturally in the body.

Althyxin contains lactose

If you have been diagnosed with intolerance to some sugars, discuss this with your doctor before taking this medicine.

Althyxin contains sodium

This medicine contains less than 1 mmol of sodium (23 mg) per tablet, which means it is considered "sodium-free".

3. How to take Althyxin

Always take this medicine exactly as your doctor has told you. If you are not sure, ask your doctor or pharmacist.
Your doctor will determine the individual dose for you based on the tests and laboratory results. Treatment usually starts with a small dose, which is increased every 2-4 weeks until the full dose, tailored to your individual needs, is reached. In the first few weeks, you will be prescribed laboratory tests to allow your doctor to adjust the dose.
If a child is born with hypothyroidism, the doctor may recommend starting treatment with a higher dose, as it is essential to quickly supplement the lack of thyroid hormones. The recommended initial dose is 10-15 micrograms per kilogram of body weight for the first three months. Then, the doctor will adjust the dose individually.
Typical dose ranges are presented in the table below. Lower doses may be sufficient for:

• the elderly,
• patients with heart disease,
• those with severe or prolonged hypothyroidism,
• those with a small body mass or giant goiter.

* Althyxin 125 micrograms, 150 micrograms, 175 micrograms, or 200 micrograms tablets are not suitable for the lower dose range, but your doctor may prescribe a lower dose of Althyxin in tablets.
Method of administration
Althyxin is intended for oral administration.
Take the entire daily dose of Althyxin in the morning, on an empty stomach (at least 30 minutes before breakfast), with a small amount of liquid, e.g., half a glass of water.
Infants should be given the entire daily dose of Althyxin once, at least 30 minutes before the first meal of the day. For this purpose, the tablet should be crushed and mixed with a small amount of water immediately before administration. The resulting suspension should be given with a small additional 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 you are taking Althyxin. Your doctor will discuss with you individually how long you need to take this medicine. Most patients need to take Althyxin for the rest of their lives.

Taking a higher dose of Althyxin than recommended

If you take a higher dose than recommended, you may experience symptoms such as rapid heartbeat, restlessness, excitement, or involuntary movements. In patients with neurological disorders such as epilepsy, single seizures have been observed. Patients at risk of psychotic disorders may experience symptoms of acute psychosis. In such cases, contact your doctor.

Missing a dose of Althyxin

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

4. Possible side effects

Like all medicines, Althyxin can cause side effects, although not everybody gets them.
If you take a higher dose of Althyxin than recommended or if you have poor tolerance to the recommended dose (e.g., rapid dose increase), you may experience the following side effects: rapid or irregular heartbeat, chest pain, headache, weakness, or muscle cramps, hot flashes (feeling of heat and facial flushing), fever, vomiting, menstrual disorders, pseudotumor cerebri (increased intracranial pressure with eye swelling), tremors, restlessness, sleep disturbances, sweating, weight loss, diarrhea.
If you experience any of these symptoms, contact your doctor. Your doctor may decide to stop treatment for a few days or reduce the dose until the symptoms disappear.
Allergic reactions to the other ingredients of Althyxin (see section 6) are possible. The frequency of occurrence is unknown. Symptoms of an allergic reaction may include facial and throat swelling (angioedema), rash, and urticaria. In this case, consult your doctor immediately.

Reporting side effects

If you experience any side effects, including those not listed in this leaflet, tell 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:
Jerozolimskie Avenue 181C, 02-222 Warsaw, phone: +48 22 49 21 301, fax: +48 22 49 21 309,
website: https://smz.ezdrowie.gov.pl
By reporting side effects, you can help gather more information on the safety of this medicine.
Side effects can also be reported to the marketing authorization holder.

5. How to store Althyxin

Keep this medicine out of the sight and reach of children.
Do not use this medicine after the expiry date stated on the blister and carton. The expiry date refers to the last day of the month.
Do not store above 25°C.
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 packaging and other information

What Althyxin contains

• The active substance of Althyxin is levothyroxine sodium.
• Each tablet contains 25, 50, 75, 100, 125, 150, 175, or 200 micrograms of levothyroxine sodium.
• The other ingredients are lactose monohydrate, cornstarch, gelatin, sodium croscarmellose, and magnesium stearate.

What Althyxin looks like and contents of the pack

Althyxin, 25 micrograms, are round, white tablets with the number "25" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 50 micrograms, are round, white tablets with the number "50" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 75 micrograms, are round, white tablets with the number "75" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 100 micrograms, are round, white tablets with the number "100" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 125 micrograms, are round, white tablets with the number "125" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 150 micrograms, are round, white tablets with the number "150" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 175 micrograms, are round, white tablets with the number "175" embossed on one side and a dividing line in the shape of a "+" on the other side.
Althyxin, 200 micrograms, are round, white tablets with the number "200" embossed on one side and a dividing line in the shape of a "+" on the other side.
The tablets are packaged in PVC/PE/PVDC/Aluminum blisters of 30, 50, 84, 90, or 100 tablets, in a carton.
Not all pack sizes may be marketed.

Marketing authorization holder

Zentiva k.s.
U Kabelovny 130
Dolní Měcholupy
102 37 Prague 10
Czech Republic

Manufacturer

Interpharma Services Ltd.
43A Cherni Vrach Blvd. 1407- Sofia
Bulgaria

This medicinal product has been authorized in the Member States of the European Economic Area under the following names:

Czech Republic, Poland: Althyxin
Netherlands:
Levothyroxine Abdi

For more information about this medicine, contact the representative of the marketing authorization holder in Poland:

Zentiva Polska Sp. z o.o.
Bonifraterska Street 17
00-203 Warsaw
phone: +48 22 375 92 00
Date of last revision of the leaflet:December 2023