25, 50, and 100 micrograms tablets 
levothyroxine sodium

Read all of this leaflet carefully before you start taking this medicine. It contains information that is important to you.

  • Save this information, 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 give it to others. It can harm them, even if they show signs of illness similar to yours.
  • If you get any side effects, talk to your doctor or pharmacist. This also applies to any side effects not mentioned in this information. See section 4.

In this leaflet: 
1. What Euthyrox is and what it is used for 
2. What you need to know before taking Euthyrox 
3. How to take Euthyrox 
4. Possible side effects 
5. How to store Euthyrox 
6. Contents of the packaging and other information 

1. What Euthyrox is and what it is used for

Levothyroxine, the active substance in Euthyrox, is a synthetic thyroid hormone for the treatment of diseases and defects of the thyroid gland. It has the same effect as the naturally occurring thyroid hormones.

Euthyrox is used

  • to treat benign goiter in patients with normal thyroid function,
  • to prevent the goiter from returning after surgery,
  • to replace natural thyroid hormones when the thyroid gland is not producing enough,
  • to inhibit tumor growth in patients with thyroid cancer,
  • to regulate thyroid hormone levels when overproduction of hormone is treated with drugs that counteract the production of thyroid hormone.

Euthyrox 100 microgram tablets are also used to examine thyroid function.

Levothyroxine contained in Euthyrox may also be approved for the treatment of other conditions not mentioned in this product information. Ask your doctor, pharmacist, or another healthcare professional if you have any further questions, and always follow their instructions.

2. What you need to know before you take Euthyrox

Do not take Euthyrox

if you have any of the following:

  • allergy (hypersensitivity) to the active substance or any of the other ingredients of Euthyrox (listed in section 6);
  • impaired function of the adrenal glands or pituitary gland and not receiving treatment for it, or severe overproduction of thyroid hormones ( thyrotoxicosis ),
  • acute heart disease (myocardial infarction or myocarditis).

Do not take Euthyrox with medicines that counteract the production of thyroid hormone if you are pregnant (see section Pregnancy and breast-feeding below).

Warnings and cautions

Talk to your doctor or pharmacist before taking Euthyrox if you have any of the following heart conditions:

  • insufficient blood flow in the blood vessels of the heart (angina)
  • heart failure
  • fast and irregular heartbeats
  • high blood pressure
  • fat deposits in artery engines (atherosclerosis)

These conditions must be treated and controlled before you start taking Euthyrox or a test to examine thyroid function is performed. You must undergo close monitoring of thyroid hormone levels while taking Euthyrox. If you are not sure if you have any of these conditions, or if they are untreated, consult a doctor.

Your doctor will check if you have a defect in the adrenal gland or pituitary gland or a defect in the thyroid gland with uncontrolled overproduction of thyroid hormones (autonomic thyroid function), as these conditions must be treated and controlled before starting Euthyrox or a test to examine thyroid function.

Blood pressure will be monitored regularly when levothyroxine treatment is started in premature infants with very low birth weight as rapid fall in blood pressure (called circulatory collapse) may occur.

Thyroid imbalance can occur if you need to change your medicine to another medicine that contains levothyroxine. Talk to your doctor if you have any questions about changing your medicine. Careful controls (clinical examination and laboratory tests) are required during the transition period. Tell your doctor if you get any side effects as this may indicate that your dose needs to be adjusted up or down.

Talk to your doctor,

  • whether you are in menopause one or after menopause; your doctor may need to have regular check-ups of thyroid function due to the risk of osteoporosis.
  • before you start or stop taking orlistat, or change your treatment with orlistat (medicines used to treat obesity; you may need more careful monitoring and dose adjustment).
  • if you experience signs of a psychotic disorder (you may need closer monitoring and dose adjustment).

Thyroid hormones should not be used to achieve weight loss. Intake of thyroid hormones does not reduce weight if your thyroid hormone level is within the normal range. Serious or even life-threatening side effects can occur if you increase the dose without consulting your doctor. High doses of thyroid hormones should not be taken with certain weight loss medicines, such as amfepramone, catching, and phenylpropanolamine, as the risk of serious or even life-threatening side effects may increase.

Other medicines and Euthyrox

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any of the following medicines, as Euthyrox may affect their effect:

  • Antidiabetic medicines (medicines that lower your blood sugar): 
    Euthyrox may reduce the effect of your anti-diabetic medicines, so you may need extra blood sugar control, especially at the beginning of your treatment with Euthyrox. While you are taking Euthyrox, you may need to adjust the dose of one of your medicines for diabetes.
  • Coumarin derivatives (medicines used to prevent blood clots): Euthyrox may increase the effect of these medicines, which may increase the risk of bleeding, especially in the elderly. You may need extra checks on your blood’s ability to coagulate, especially at the beginning and during treatment with Euthyrox. While you are taking Euthyrox, you may need to adjust the dose of one of the coumarin medicines.

If you have to take any of the following medicines, make sure you follow the recommended time intervals:

  • Medicines used to bind bile acids and to lower high cholesterol (cholestyramine or colestipol): Be 
    sure to take Euthyrox 4-5 hours before taking these medicines, as they may block the absorption of Euthyrox from the intestine.
  • Antacids (relieves heartburn and acid reflux), sucralfate (for stomach or intestinal ulcers), other medicines containing aluminum, medicines containing iron, medicines containing calcium: 
    Make sure you take Euthyrox at least 2 hours before taking these medicines, as otherwise, it may reduce the effect of Euthyrox.

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any of the following medicines, as these may reduce the effect of Euthyrox:

  • propylthiouracil (a drug that inhibits the production of thyroid hormone)
  • glucocorticoids (medicines for allergies and inflammation )
  • beta-blockers (antihypertensive drugs that are also used to treat heart disease)
  • sertraline (antidepressant)
  • chloroquine or proguanil (medicines to prevent or treat malaria )
  • medicines that activate certain liver enzymes, such as barbiturates (sedatives, sleeping pills) or carbamazepine (medicines for epilepsy, which are also used for certain forms of pain and depression)
  • estrogen-containing drugs are used as hormone replacement during and after menopause or to prevent pregnancy.
  • sevelamer (a phosphate-binding drug used to treat patients with chronic kidney failure )
  • Tyrosine kinase inhibitors (medicines for cancer and inflammation )
  • orlistat (a medicine used to treat obesity)

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any of the following medicines, as they may potentiate the effect of Euthyrox:

  • salicylates (medicines used to relieve pain and reduce fever)
  • dicumarol (medicine that prevents blood clots)
  • furosemide in high doses of 250 mg ( diuretic )
  • clofibrate (medicines that lower blood lipid levels)

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any of the following medicines, as they may affect the effect of Euthyrox:

  • ritonavir, indinavir, lopinavir ( protease inhibitors, medicines used to treat HIV infection )
  • phenytoin (drugs against epilepsy )

You may need regular check-ups of your thyroid hormone levels. It may be necessary to adjust dose one of Euthyrox.

Tell your doctor if you are taking amiodarone (a medicine used to treat irregular heartbeats), as this medicine may affect thyroid function and activity.

If you have to undergo a diagnostic test or X-ray with contrast agents that contain iodine, you must tell your doctor that you are taking Euthyrox, as you may receive an injection that may affect thyroid function.

Tell your doctor or pharmacist if you are taking or have recently taken any other medicines, including medicines obtained without a prescription.

Euthyrox with food and drink

Tell your doctor if you eat soy products, especially if you change the amount you eat. Soy products may reduce the absorption of Euthyrox from the intestine and therefore it may be necessary to adjust Euthyrox- dose one.

Pregnancy and breastfeeding

If you are pregnant, you should continue to take Euthyrox. Talk to your doctor, as does one may need to be changed.

If you have taken Euthyrox with medicines that counteract the production of thyroid hormones and are given to treat an overproduction of thyroid hormones, your doctor will stop taking Euthyrox when you become pregnant.

If you are breast-feeding, continue to take Euthyrox according to your doctor’s instructions. The amount of drug excreted in breast milk is so small that it does not affect the baby.

Driving and using machines

No studies on the ability to drive and use machines have been performed. 
Euthyrox is not expected to affect the ability to drive or use machines, as levothyroxine is identical to the naturally occurring thyroid hormone.

You are responsible for assessing whether you are fit to drive a motor vehicle or perform work that requires sharpened attention. One of the factors that can affect your ability in these respects is the use of drugs due to their effects and/or side effects. Descriptions of these effects and side effects can be found in other sections. Read all the information in this leaflet for guidance. If you are not sure, talk to your doctor or pharmacist.

Important information about some of the ingredients of Euthyrox

This medicine contains less than 1 mmol sodium (23 mg) per tablet, ie essentially ‘sodium-free’.

3. How to take Euthyrox

Always take this medicine exactly as your doctor or pharmacist has told you. Ask your doctor or pharmacist if you are unsure.

Your doctor will determine your individual dose based on examinations and laboratory tests. You should usually start with a low dose that is increased at 2-4 week intervals until you reach your total individual dose. During the initial weeks of treatment, you will have to make return visits for laboratory tests so that the dose can be adjusted.

If your child is born with hypothyroidism, your doctor may recommend a higher starting dose as prompt replacement is important. The recommended starting dose is 10 to 15 micrograms per kg body weight per day for the first 3 months. Dose one is then adjusted individually by your doctor.

The usual dose range is given in the table below. A lower individual dose may be sufficient

  • if you are an elderly patient,
  • if you have heart problems,
  • if you have a serious thyroid problem or if it has been going on for a long time,
  • if you have low body weight or a large goiter.

Use of Euthyrox Recommended daily dose of Euthyrox
to treat goiter in patients with normal thyroid function 75–200 micrograms
to prevent the goiter from returning after surgery 75–200 micrograms
to replace natural thyroid hormones when the thyroid gland is not producing enough adults children
starting dose 25–50 micrograms 12.5–50 micrograms
maintenance dose 100–200 micrograms 100–150 micrograms per m 2 body surface area
to inhibit tumor growth in patients with thyroid cancer 150-300 micrograms
to regulate thyroid hormone levels when overproduction of hormone is treated with drugs that counteract the production of thyroid hormone 50–100 micrograms
to test thyroid function Euthyrox 100 microgram tablets: 
200 micrograms (2 tablets) starting 2 weeks before the test.

Euthyrox should be swallowed. 
Take one dose a day on an empty stomach in the morning (at least half an hour before breakfast), preferably with a little liquid, such as half a glass of water. 
Young children can receive the full daily dose of Euthyrox at least half an hour before the first meal of the day. 
Immediately before use, crush the tablet and mix it with a little water and give it to the baby along with a little more liquid. Always prepare the mixture just before use.

Duration of treatment The duration of 
treatment may vary depending on the condition you are using Euthyrox for. Your doctor will therefore discuss with you how long you need to take the medicine. Most patients have to take Euthyrox for life.

If you take more Euthyrox then you should

If you have ingested too much medicine or if e.g. If a child has inadvertently ingested the medicine, contact a doctor, hospital, or the Poison Information Center for risk assessment and advice.

If you have taken a higher dose than prescribed, you may experience symptoms such as rapid heartbeat, anxiety, worry, or unintentional movements. In patients with a disease that affects the neurological system such as epilepsy, seizures may occur in isolated cases. In patients with a predisposition to psychotic disorders, symptoms of acute psychosis may occur. If any of these happen to you, contact your doctor.

If you forget to take Euthyrox

Do not take a double dose to make up for a forgotten tablet, but take the usual dose the next day.

If you have any further questions on the use of Euthyrox, talk to your doctor or pharmacist.

4. Possible side effects

Like all medicines, Euthyrox can cause side effects, although not everybody gets them.

You may get one or more of the following side effects if you take too much Euthyrox, or if you do not tolerate the prescribed dose (for example, when dose one is raised quickly):

Irregular or rapid heartbeat, chest pain, headache, muscle weakness or cramps, swelling (heat and redness of the face), fever, vomiting, menstrual disorders, pseudotumor cerebri (increased fluid pressure in the skull), tremors, restlessness, sleep disturbances, sweating, sweating.

If you get any of these side effects, talk to your doctor. Your doctor may stop treatment for a few days or reduce your daily dose until the side effects have disappeared.

Allergic reactions to any of the ingredients in Euthyrox are possible (see section 6. “Content declaration”). Allergic reactions may include skin rash, hives, and swelling of the face or throat ( angioedema ). If this happens, consult a doctor immediately.

If any of the side effects gets serious, or if you notice any side effects not listed in this leaflet, please tell your doctor or pharmacist.

5. How to store Euthyrox

Keep this medicine out of the sight and reach of children.

Use Euthyrox before the expiry date which is stated on the blister and carton after EXP. or EXP. The expiration date is the last day of the specified month. 
Do not store above 25 ° C. Store the blisters in the outer carton. Sensitive to light.

The medicine should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures will help to protect the environment.

6. Contents of the packaging and other information

Content declaration

  • The active substance is levothyroxine. Each tablet contains 25, 50, and 100 micrograms of levothyroxine sodium, respectively.
  • The other ingredients are corn starch, citric acid, croscarmellose sodium, gelatin, magnesium stearate, and mannitol (E421).

What the medicine looks like and the contents of the pack

The Euthyrox tablets are white, round, flat on both sides, with a beveled edge, partial notch, and an inscription on one side: 
EM 25, EM 50, or EM 100.

Euthyrox is available in packs of 20, 25, 30, 50, 60, 90, 100, or 500 tablets or calendar packs of 28 or 84 tablets.

Not all pack sizes may be marketed.

Marketing Authorization Holder and Manufacturer:

Marketing Authorisation Holder

Merck AB 
Box 3033

169 03 Solna

Tel: 08-562 445 00


Merck Healthcare KGaA

Frankfurter Strasse

64293 Darmstadt, Germany


Avda. Leganés, 62

Alcorcón, 28923 Madrid


This medicinal product is authorized under the European Economic Area under the names:

Denmark: Euthyrox

Greece: Euthyrox

Iceland: Euthyrox

Croatia: Euthyrox

Norway: Euthyrox

Portugal: Eutirox

Spain: Eutirox

Germany: Euthyrox

Austria: Euthyrox

Muhammad Nadeem

Leave a Reply