Althyxin

Package leaflet: 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
Levothyroxinum natricum
Please read the entire leaflet carefully before using this medicine, as it contains
important information for the patient.

• Keep this leaflet for future reference.
• If you have any questions, please consult your doctor or pharmacist.
• This medicine has been prescribed for a specific individual. Do not share it with others. This medicine may harm other people, even if their symptoms appear identical.
• If you experience any adverse reactions, including any not listed in this leaflet, inform your doctor or pharmacist. See section 4.

Table of contents

1. What Althyxin is and what it is 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 pack and other information

1. What Althyxin is and what it is used for

The active substance in Althyxin is levothyroxine, a synthetic thyroid hormone used in the treatment of thyroid dysfunction and thyroid disorders. It has the same action as the thyroid hormone naturally produced in the body.
Althyxin is used:

• for the treatment of mild goitre in patients with normal thyroid function,
• to prevent recurrence of goitre after surgery,
• to replace deficient natural thyroid hormones when the thyroid gland does not produce sufficient amounts of hormones,
• to suppress tumour growth in patients with thyroid cancer. Althyxin is also used to normalize thyroid hormone levels when antithyroid drugs are administered due to excessive production of thyroid hormones. Althyxin 100 micrograms, 150 micrograms, and 200 micrograms may also be used in tests assessing thyroid function.

2. Important information before using Althyxin

When not to take Althyxin:

• if the patient is allergic (hypersensitive) to the active substance or any of the other components of Althyxin (listed in section 6),
• if the patient has untreated pituitary dysfunction or if thyroid hormones are produced in excessive amounts (hyperthyroidism),
• in case of adrenal insufficiency (adrenal cortex failure) and if the patient is not receiving appropriate replacement therapy,
• in case of acute heart disease (myocardial infarction or myocarditis).

During pregnancy, Althyxin must not be taken simultaneously with antithyroid drugs (medicines for hyperthyroidism) (see section "Pregnancy and breastfeeding").

Warnings and precautions

Before starting Althyxin, discuss this with your doctor or pharmacist if the patient has any of the following heart conditions:

• inadequate blood flow in the blood vessels of the heart (angina pectoris),
• heart failure,
• rapid or irregular heartbeat,
• high blood pressure (hypertension),
• fatty deposits in the arteries (atherosclerosis).

These conditions must be treated before starting Althyxin or before performing a thyroid suppression test. During treatment with Althyxin, 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.

If the patient has adrenal insufficiency (adrenal cortex failure), consult a doctor before taking Althyxin. The doctor will perform appropriate tests to determine whether the patient has adrenal, pituitary, or thyroid dysfunction with uncontrolled overproduction of thyroid hormones (autonomous thyroid function), as appropriate treatment or a thyroid suppression test may be required before starting Althyxin.

Discuss with the doctor:

• if the patient is perimenopausal or postmenopausal; the doctor may recommend regular monitoring of thyroid function due to the risk of osteoporosis;
• if the patient switches from one levothyroxine-containing medicine to another; the effects of these medicines may differ slightly, so more frequent monitoring and dose adjustment may be necessary;
• before starting, stopping, or changing treatment with orlistat (a medicine used to treat obesity), as more frequent monitoring and appropriate dose adjustment may be required;
• in case of symptoms of psychotic disorders, as more frequent monitoring and appropriate dose adjustment may be necessary;
• if laboratory tests to measure thyroid hormone levels are planned, the patient should inform the doctor or laboratory staff about current or recent use of biotin (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 increased or falsely decreased due to biotin intake. The doctor may advise the patient to discontinue biotin before laboratory testing. Also note that other products the patient may be taking, such as multivitamin preparations or supplements for hair, skin, and nails, may also contain biotin, which could affect laboratory test results. If the patient takes such products, they should inform the doctor or laboratory staff (see section "Althyxin with other medicines").

Althyxin with other medicines

Tell your doctor or pharmacist about all medicines the patient is currently taking or has recently taken, as Althyxin may affect the action of the following medicines:

• Antidiabetic medicines (medicines that lower blood sugar): Althyxin may reduce the effect of blood sugar-lowering medicines, which may require additional monitoring of blood glucose (sugar) levels, especially at the beginning of Althyxin treatment. During Althyxin treatment, adjustment of the antidiabetic medicine dose may be necessary.

• Coumarin derivatives (medicines used to prevent blood clots): Althyxin may enhance the effect of these medicines, increasing the risk of bleeding, especially in elderly patients. Therefore, periodic monitoring of blood coagulation parameters may be necessary before starting and during Althyxin treatment. During Althyxin treatment, adjustment of the dose of the coumarin derivative may be necessary.

Observe the recommended time intervals between taking Althyxin and the following medicines:

• Bile acid sequestrants and cholesterol-lowering medicines (e.g. cholestyramine or colestipol): Althyxin should be taken 4 to 5 hours before these medicines, as they may inhibit the intestinal absorption of Althyxin.

• Antacids (used to relieve indigestion), sucralfate (used to treat gastric or duodenal ulcers), other medicines containing aluminium, iron-containing medicines, calcium-containing medicines: Althyxin should be taken at least 2 hours before these medicines, otherwise they may reduce the effectiveness of Althyxin.

Discuss with the doctor or pharmacist if the patient is taking or has recently taken any of the following medicines, as they may reduce the effectiveness of Althyxin:

• propylthiouracil (an antithyroid medicine),
• glucocorticoids (anti-allergic and anti-inflammatory medicines),
• beta-adrenergic blockers (medicines that lower blood pressure, also used in heart disease),
• sertraline (an antidepressant),
• chloroquine or proguanil (medicines used to prevent or treat malaria),
• medicines that induce certain liver enzymes, e.g. barbiturates (sedatives and hypnotics), carbamazepine (an antiepileptic, also used in certain types of pain and depressive disorders), or medicines containing St. John's wort (some herbal medicines),
• oestrogen-containing medicines, used in hormone replacement therapy during and after menopause or for contraception,
• 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 omeprazole, esomeprazole, pantoprazole, rabeprazole, and lansoprazole) used to reduce stomach acid production, which may impair intestinal absorption of levothyroxine and reduce its effectiveness. If the patient is taking levothyroxine during treatment with proton pump inhibitors, the doctor should monitor thyroid function and adjust the Althyxin dose if necessary.

Discuss with the doctor or pharmacist if the patient is taking or has recently taken any of the following medicines, as they may enhance the effect of Althyxin:

• salicylates (pain-relieving and antipyretic medicines),
• dicoumarol (a medicine that reduces blood clotting),
• high-dose furosemide (≥250 mg) (a diuretic),
• clofibrate (a medicine that lowers blood lipid levels).

Discuss with the doctor or pharmacist if the patient is taking or has recently taken any of the following medicines, as they may affect the action of Althyxin:

• protease inhibitors (ritonavir, indinavir, lopinavir) used in the treatment of HIV and chronic hepatitis C, phenytoin (an antiepileptic).

If the patient is currently taking or has recently taken 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"). Regular monitoring of thyroid hormone levels and dose adjustment of Althyxin may be necessary.

Thyroid function imbalance may occur if switching to another levothyroxine-containing medicine. In case of any questions regarding such a switch, consult a doctor. Close clinical and biological monitoring is required during the transition period. Inform the doctor if any adverse effects occur, as this may indicate the need to increase or decrease the dose.

Inform the doctor if the patient is taking amiodarone (a medicine used to treat irregular heartbeat), as this medicine may affect thyroid function.

Inform the doctor if an X-ray or other diagnostic test with an iodine-containing contrast agent is required, as Althyxin must be reported because such tests involve injections that may affect thyroid function.

Inform the doctor or pharmacist if the patient is taking or has recently taken any other medicines, including those available without a prescription.

Thyroid hormones are not suitable for weight reduction. Taking thyroid hormones will not lead to weight loss if thyroid hormone levels are within the normal range. Increasing the dose of the medicine without medical advice may lead to severe and life-threatening adverse effects, especially when taken in combination with other weight-reducing medicines.

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

Taking Althyxin with food and drink

Inform the doctor if the patient's diet includes soy-containing products, especially if the patient changes the proportion of these products in their diet. Soy-containing products may reduce the intestinal absorption of Althyxin, which may necessitate dose adjustment.

Pregnancy and breastfeeding

If the patient is pregnant, continue taking Althyxin, but discuss this with the doctor, as dose adjustment may be necessary.

If the patient is taking Althyxin together with antithyroid medicines used to treat hyperthyroidism, the doctor will advise discontinuing Althyxin during early pregnancy.

If the patient is breastfeeding, she may continue taking Althyxin as directed by the doctor. The amount of medicine excreted in breast milk is so low that it does not affect the infant.

Driving and operating machinery

No studies on the effect on the ability to drive and operate machinery have been conducted. No effect of Althyxin on the ability to drive and operate machinery is expected, as the levothyroxine contained in this medicine is identical to the thyroid hormone naturally present in the body.

Althyxin contains lactose

If the patient has been diagnosed with an intolerance to certain sugars, discuss this with the doctor before starting this medicine.

Althyxin contains sodium

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

3. How to take Althyxin

This medicine should always be taken exactly as prescribed by the doctor. In case of doubt, consult the
doctor or pharmacist.
The doctor will determine the individual dose for the patient based on examinations and laboratory test
results. 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, laboratory tests will be ordered for the patient, allowing the doctor to adjust the appropriate dose.
If a child was born with hypothyroidism, the doctor may recommend starting treatment with a higher dose, as it is important to rapidly correct the thyroid hormone deficiency. The recommended initial dose is 10 micrograms to 15 micrograms per kilogram of body weight during the first 3 months.
Afterwards, the doctor will individually adjust the dose.
Typical dosage ranges are shown in the table below. Lower doses may be sufficient for individuals:

• of advanced age,
• with heart disease,
• with severe or long-standing hypothyroidism,
• with low body weight or with giant goitre.

* Althyxin tablets 125 micrograms, 150 micrograms, 175 micrograms or 200 micrograms
are not suitable for the lower dosage range indicated; however, the physician may prescribe a lower dose of
Althyxin tablets.
Method of administration
Althyxin is intended for oral administration.
The full 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 Althyxin should be administered once daily, at least half an hour
before the first meal of the day. To achieve this, the tablet should be crushed and mixed with a small
amount of water immediately before administration. This suspension should then be given with a small
additional amount of liquid. A fresh suspension must be prepared each time before administration.
Duration of treatment
The duration of treatment may vary depending on the reason for which the patient is taking Althyxin.
The physician will discuss with the patient individually how long the treatment should continue. Most
patients need to take Althyxin for life.
Administration of a higher than recommended dose of Althyxin
If a higher than recommended dose is taken, symptoms such as rapid heartbeat, anxiety, agitation or
involuntary movements may occur. In patients with pre-existing neurological disorders such as epilepsy,
isolated seizures have been observed. Patients at risk of psychotic disorders may experience symptoms of
acute psychosis. In such cases, contact the physician immediately.
Missed dose of Althyxin
Do not take a double dose to make up for a missed dose. On the following day, resume the usual dose.
If in doubt regarding the use of this medicinal product, consult a physician or pharmacist.

4. Possible adverse reactions

Like all medicines, Althyxin may cause adverse reactions, although not everyone experiences them.
If a higher dose of Althyxin than recommended is taken, or if the recommended dose is poorly tolerated
(e.g. due to rapid dose escalation), the following adverse reactions may occur: rapid or
irregular heartbeat, chest pain, headache, weakness or muscle cramps, hot flushes (feeling of warmth and facial flushing), fever, vomiting, menstrual disorders, pseudotumor cerebri (increased intracranial pressure with optic disc swelling), tremor, motor restlessness, sleep disturbances, sweating, weight loss, diarrhoea.
If any of the above symptoms occur, contact your doctor. The doctor may decide to interrupt treatment for several days or reduce the dose until symptoms resolve.
Hypersensitivity reactions to other components of Althyxin are possible (see section 6. "What Althyxin contains"). Frequency of occurrence is unknown. Symptoms of hypersensitivity may include facial and throat swelling (angioedema), rash and urticaria. In such cases, seek immediate medical attention.
Reporting of adverse reactions
If any adverse reactions occur, 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 at 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
Reporting adverse reactions helps to gather further information on the safety of the medicine.
Adverse reactions can also be reported to the marketing authorization holder.

5. How to store Althyxin

Keep this medicine out of 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 stated month.
Do not store above 25°C.
Medicines must not be disposed of via wastewater or household waste.
Ask your pharmacist how to dispose of medicines no longer required. Such practices help protect the environment.

6. Contents of the pack and other information

What Althyxin contains

• The active substance 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, maize starch, 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 cross-shaped break line ("+") on the other side.
Althyxin 50 micrograms are round, white tablets with the number "50" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 75 micrograms are round, white tablets with the number "75" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 100 micrograms are round, white tablets with the number "100" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 125 micrograms are round, white tablets with the number "125" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 150 micrograms are round, white tablets with the number "150" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 175 micrograms are round, white tablets with the number "175" embossed on one side and a cross-shaped break line ("+") on the other side.
Althyxin 200 micrograms are round, white tablets with the number "200" embossed on one side and a cross-shaped break line ("+") on the other side.
The tablets are packed in PVC/PE/PVDC/Aluminium blisters containing 30, 50, 84, 90 or 100 tablets, in a cardboard box.
Not all pack sizes may be marketed.

Marketing Authorisation 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 is authorised in the member states of the European Economic Area under the following names:
Czech Republic, Poland: Althyxin
Netherlands: Levothyroxine Abdi

For further information about this medicinal product, please contact the local representative of the Marketing Authorisation Holder in Poland:
Zentiva Polska Sp. z o.o.
ul. Bonifraterska 17
00-203 Warsaw
tel.: +48 22 375 92 00