Althyxin

Package leaflet: Information for the patient

Althyxin, 25 micrograms/5 mL, oral solution
Althyxin, 50 micrograms/5 mL, oral solution
Althyxin, 100 micrograms/5 mL, oral solution
Levothyroxinum natricum
Please read this leaflet carefully before taking this medicine because it contains important information for you.

• 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 personally. Do not give it 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, tell your doctor or pharmacist. See section 4.

Leaflet contents

1. What Althyxin is and what it is used for
2. What you need to know 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 sodium.
Althyxin is used in the treatment of hypothyroidism—a condition in which the thyroid gland does not produce enough thyroxine to meet the body's needs.
Althyxin is also used in the treatment of thyroid cancer and non-toxic diffuse goitre or Hashimoto's thyroiditis—conditions in which the thyroid gland enlarges, causing swelling in the front part of the neck.

2. Important information before using Althyxin

Do not take Althyxin if the patient has:

• hypersensitivity (allergy) to sodium levothyroxine or any of the other ingredients of this medicine (listed in section 6),
• adrenal insufficiency and the patient is not receiving adequate corticosteroid replacement therapy,
• untreated pituitary dysfunction or if thyroid hormones are being produced in excess (hyperthyroidism),
• myocardial infarction (acute heart attack), myocarditis (acute inflammation of the heart muscle), or pericarditis (acute inflammation of the layers surrounding the heart). This medicine must not be taken simultaneously with other medicines used to treat hyperthyroidism if the patient is pregnant (see section "Pregnancy and breastfeeding").

Warnings and precautions
Before starting Althyxin, consult a doctor or pharmacist if:

• the patient has heart disease, circulatory disorders, or high blood pressure,
• the patient has hyperthyroidism (overactive thyroid gland), adrenal insufficiency, diabetes, or has had hypothyroidism for some time,
• the patient is scheduled for laboratory tests measuring thyroid hormone levels. 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 elevated or falsely decreased due to biotin intake. The doctor may advise the patient to discontinue biotin before laboratory testing. It is also important to note that other products the patient may be taking, such as multivitamin preparations 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 the doctor or laboratory staff (see information in section "Althyxin and other medicines").

When switching from one medicine to another containing levothyroxine, thyroid hormone balance may be disturbed. Consult a doctor if the patient has any questions regarding changing medicines. Close monitoring of clinical and biochemical parameters is required during the transition period. Inform the doctor if any adverse effects occur, as dose adjustment may be necessary.
Thyroid hormones are not suitable for weight reduction. Taking them 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 the medicine is taken in combination with other weight-reducing medicines.

Children
During the first few months of treatment, partial hair loss may occur, but this effect is usually temporary and hair typically regrows later.
Particular caution is required when initiating levothyroxine treatment in preterm infants with very low birth weight. Blood pressure should be monitored regularly in these infants, as a sudden drop in blood pressure (so-called circulatory collapse) may occur (see section 4).

Althyxin and other medicines
Inform the doctor or pharmacist about all medicines currently or recently taken, as well as any medicines the patient plans to take.
Althyxin may affect the action of certain medicines, and certain medicines may affect the action of Althyxin. It is especially important to inform the doctor or pharmacist if the patient is taking:

• anticoagulants (e.g. warfarin),
• antidepressants (e.g. sertraline, imipramine, amitriptyline),
• antiepileptic medicines (e.g. phenytoin, phenobarbital, carbamazepine),
• antidiabetic medicines,
• rifampicin (used to treat infections, particularly tuberculosis),
• digoxin or amiodarone (used in heart diseases),
• propranolol (used to treat high blood pressure), lovastatin (used to treat high cholesterol), or phenylbutazone or acetylsalicylic acid (anti-inflammatory medicines),
• estrogens, estrogen-containing medicines, and oral contraceptives, androgens, or corticosteroids,
• other medicines, including those purchased without a prescription,
• sucralfate, cimetidine, or aluminum hydroxide (used to treat gastric ulcers),
• other medicines containing aluminum,
• lithium (used to treat depression, mood disorders, and anxiety disorders),
• cholestyramine or colestewelam (used to reduce cholesterol levels), sodium polystyrene sulfonate, calcium or iron supplements,
• products containing St. John's wort (herbal remedy).

Althyxin may be taken with the following medicines, but not at the same time:

• chloroquine or proguanil (used for malaria prophylaxis),
• protease inhibitors (e.g. ritonavir, indinavir, lopinavir) used in the treatment of HIV infection,
• sevelamer (used to treat high blood phosphate levels in patients with kidney failure),
• tyrosine kinase inhibitors (e.g. imatinib, sunitinib) used in cancer treatment,
• propylthiouracil (used to treat hyperthyroidism),
• β-adrenergic blockers (used to treat high blood pressure and heart diseases),
• sympathomimetics (medicines acting by stimulating the sympathetic nervous system),
• glucocorticosteroids (steroid hormones used to treat adrenal insufficiency and other diseases),
• iodine-containing contrast agents (used to enhance visibility of blood vessels and organs during radiographic procedures),
• orlistat (a medicine used to treat obesity).

If hospitalization or surgery is planned, inform the anesthesiologist or other medical staff about taking Althyxin. The medicine may interact with the anesthetic agent (ketamine), which may be administered before surgery.
If the patient is currently or recently taking 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").
Proton pump inhibitors (such as omeprazole, esomeprazole, pantoprazole, rabeprazole, and lanzoprazol) are used to reduce stomach acid production, which may impair levothyroxine absorption from the intestine and reduce its effectiveness. If the patient is taking levothyroxine during treatment with proton pump inhibitors, the doctor should monitor thyroid function and, if necessary, adjust the dose of Althyxin.

Althyxin with food and drink
Soy-containing products (soy supplements) may interact with levothyroxine. Consult a doctor or pharmacist.

Pregnancy and breastfeeding
Consult a doctor or pharmacist before taking any medicine.
If the patient is pregnant or breastfeeding, suspects she may be pregnant, or is planning to have a child, she should consult a doctor or pharmacist before using this medicine.

Driving and operating machinery
It is unlikely that this medicine affects the ability to drive or operate machinery.

Althyxin contains sodium methyl parahydroxybenzoate, glycerol, and sodium
Sodium methyl parahydroxybenzoate may cause allergic reactions (delayed-type reactions possible).
Glycerol may cause headache, gastrointestinal disturbances, and diarrhea.
This medicine contains less than 1 mmol (23 mg) of sodium per 5 mL, meaning the medicine is considered "sodium-free".

3. How to use Althyxin

This medicine should always be taken exactly as recommended by your doctor or pharmacist. If you have any doubts,
you should consult your doctor or pharmacist.
Your doctor will determine the individual dose for you based on your condition. Your doctor will arrange for regular blood tests at scheduled intervals to monitor your response to treatment.
If switching from a levothyroxine oral solution to tablets or from tablets to a levothyroxine oral solution, your doctor will closely monitor your condition. The same applies when switching from one oral levothyroxine solution to another.

Typical daily doses are:
Adults and children over 12 years of age:
The initial dose is 50 to 100 micrograms per day, increased by 25 to 50 micrograms every 3 to 4 weeks until the appropriate dose for the patient is reached. The usual maintenance dose is typically 100 to 200 micrograms per day.
For diffuse non-toxic goitre or Hashimoto's thyroiditis, the recommended dose is 50 to 200 micrograms per day.
For treatment of thyroid cancer, the recommended dose is 150 to 300 micrograms per day.

Elderly patients (over 50 years of age):
The initial dose is 12.5 micrograms per day, increased by 12.5 micrograms every 2 to 4 weeks until the correct dose is reached. The usual target dose range is 50 to 200 micrograms per day. This dose also applies to patients with severe hypothyroidism and those with heart disease.

Children under 12 years of age:
The dose for children depends on their age, weight, and the condition being treated. Children should be monitored to ensure they receive the appropriate dose. The medicine should be given to the child in the morning or evening, before feeding or with food, but it must be administered daily in the same manner.

Congenital hypothyroidism in newborns and infants:
Initially 10 to 15 micrograms/kg body weight per day for the first 3 months. The dose will then be adjusted according to the response to treatment.

Acquired hypothyroidism in children:
Initially 12.5 to 50 micrograms per day. The dose should be gradually increased every 2 to 4 weeks depending on the response to treatment.

To administer the prescribed dose, use the provided oral syringe – see instructions below.
The syringe can be used to measure the dose by drawing up the liquid to the appropriate mark on the syringe. For example, if the patient's dose is 50 micrograms per day, the corresponding volume will be:
For 25 micrograms/5 mL strength – 2 x 5 mL (total 10 mL)
For 50 micrograms/5 mL strength – 5 mL
For 100 micrograms/5 mL strength – 2.5 mL

How to use the oral syringe:

1. Shake the bottle well, making sure the cap is tightly secured on the bottle.
2. Remove the cap. Caution: Keep the cap nearby to close the bottle after each use.
3. Insert the plastic connector into the neck of the bottle. Caution: The connector must always remain in the bottle.
4. Take the syringe and check that the plunger is fully depressed.
5. Hold the bottle upright and firmly connect the oral syringe to the plastic connector.
6. Turn the entire bottle with the syringe attached upside down.
7. Slowly pull back the plunger to fill the syringe with the medicine. Push the plunger back fully to expel any large air bubbles that may have become trapped in the oral syringe.
8. Then slowly pull back the plunger to the volume required for the prescribed dose.
9. Turn the entire bottle with the syringe upright and remove the syringe from the bottle.
10. The dose can now be swallowed directly from the oral syringe. Ensure the patient is sitting upright. The plunger should be pressed slowly to allow the dose to be swallowed.
11. After use, replace the child-resistant cap, leaving the connector in place.
12. Cleaning: After use, wipe the outside of the syringe with a clean, dry cloth.

Method of administration
Althyxin must be swallowed. Althyxin should be taken on an empty stomach, usually before breakfast.

Duration of treatment
Treatment usually lasts for life in cases of hypothyroidism, diffuse non-toxic goitre, or Hashimoto's thyroiditis.

Use of a higher than recommended dose of Althyxin
If an overdose is accidentally taken, contact your doctor immediately or go to the nearest hospital emergency department. Symptoms of overdose include fever, irregular heartbeat, muscle cramps, headache, restlessness, flushing, sweating, or diarrhoea. Always bring the medicine taken, its container, and label with you so it can be identified.

Missed dose of Althyxin
If a dose is missed, take it as soon as you remember, and then take the next dose at the usual time. Do not take a double dose to make up for a missed dose. If several doses are missed, inform your doctor at your next scheduled follow-up visit or blood test.

Stopping Althyxin treatment
For treatment to be effective, Althyxin must be taken regularly at the doses prescribed by your doctor. Under no circumstances should you change, interrupt, or discontinue the prescribed treatment without consulting your doctor. Symptoms of the disease may return if treatment is stopped or discontinued prematurely. The type of symptoms depends on the underlying condition.

If you have any further questions about the use of this medicine, consult your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.
They usually occur when the dose of medicine taken is too high.
If any of the following symptoms occur, stop taking Althyxin immediately
and contact a doctor or go to the emergency department of the nearest hospital:

• swelling of the hands, feet, ankles, face, lips, mouth or throat, which may cause difficulty in swallowing or breathing;
• hives;
• fainting;
• yellowing of the skin and whites of the eyes, also known as jaundice.

These are very serious side effects. If they occur, the patient may be experiencing a severe allergic reaction to
Althyxin. Immediate medical assistance or hospitalization may be required. All of these very serious side effects occur very rarely.
If any of the following symptoms occur, inform your doctor:
Rapid or irregular heartbeat, palpitations, chest pain, muscle cramps or weakness, headache, anxiety, restlessness, hot flushes, circulatory collapse in preterm infants with low birth weight (see section 2), sweating, diarrhoea, vomiting, fever, menstrual disorders, increased intracranial pressure, tremor, insomnia, heat intolerance and excessive weight loss.
Angioedema, rash, urticaria, itching and oedema may also occur.
Very rarely, following ingestion of a single excessive dose of Althyxin or after taking excessive doses of this medicine over many years, heart failure may develop. Coma and death have also been reported.
If an unusual, severe feeling of unwellness occurs, inform your doctor as soon as possible.
Additional side effects occurring in children
At the beginning of treatment, hair loss may occur in children, but this is usually temporary and hair regrows.
Reporting of side effects
If any side effects occur, including any not listed in this leaflet, tell your doctor, pharmacist or nurse. Side effects can be reported directly to the Department of Monitoring of Adverse Drug Reactions 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 or its representative in Poland.
Reporting side effects helps provide more information on the safety of this medicine.

5. How to store Althyxin

Keep this medicine out of the sight and reach of children.
Expiry date
The shelf life after first opening the bottle is 8 weeks.
Do not use this medicine after the expiry date stated on the label and carton after EXP.
The expiry date refers to the last day of the stated month.
Storage conditions
Do not store above 25°C.
Keep in the original packaging to protect from light.
Do not use this medicine if you notice any changes in appearance or smell. Consult your
pharmacist.
Medicines must not be disposed of via wastewater or household waste. Ask your
pharmacist how to dispose of medicines no longer required. Such measures will help protect the environment.

6. Contents of the package and other information

What Althyxin contains

• The active substance is levothyroxine sodium. Althyxin 25 micrograms/5 mL oral solution: Each 5 mL of oral solution contains levothyroxine equivalent to 25 micrograms of levothyroxine sodium. Althyxin 50 micrograms/5 mL oral solution: Each 5 mL of oral solution contains levothyroxine equivalent to 50 micrograms of levothyroxine sodium. Althyxin 100 micrograms/5 mL oral solution: Each 5 mL of oral solution contains levothyroxine equivalent to 100 micrograms of levothyroxine sodium.
• The other ingredients are: glycerol, monohydrate citric acid, sodium methyl parahydroxybenzoate, sodium hydroxide (for pH adjustment), and purified water.

What Althyxin looks like and contents of the pack
Althyxin is a clear, colourless liquid. Each amber glass bottle (type III) with an HDPE/PP closure and child-resistant cap with tamper-evident seal contains 75 mL or 100 mL of levothyroxine sodium oral solution.
Althyxin is available in packs containing either one glass bottle of 75 mL or 100 mL of oral solution, or two glass bottles each containing 75 mL of oral solution.
A 5 mL syringe with 0.1 mL graduations to facilitate dose measurement is also included.
Not all pack sizes may be marketed.

Marketing Authorisation Holder
Zentiva, k.s.,
U kabelovny 130
Dolní Měcholupy
102 37 Prague 10
Czech Republic
(logo of the marketing authorisation holder)

Manufacturer
Galenica Pharmaceutical Industry S.A.
3rd km Old National Road Chalkida-Athens
34100 Glifa Chalkida Eubia
Greece

This medicinal product is authorised in the Member States of the European Economic Area under the following names:
Germany L-Thyroxin Zentiva
Poland Althyxin
Portugal Alverox

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