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  • Thyroid medicine
  • For various thyroid disorders
  • Take on an empty stomach
  • Avoid soy-based products while taking this medicine

About Levothyroxine

Levothyroxine is a synthetic version of the hormone thyroxine, which is produced naturally by the thyroid gland. It has the same effect as naturally occurring thyroid hormones.

This medicine is available in various strengths and is used for various purposes:

  • To treat a benign condition in which the thyroid gland grows larger (goiter) in patients with a normally functioning thyroid gland.
  • To prevent a goiter from recurring after surgery.
  • To treat a condition known as hypothyroidism (when the thyroid gland does not produce enough thyroxine) by replacing the hormones that your thyroid gland cannot produce.
  • To suppress the growth of thyroid cancer cells.
  • To restore the balance of thyroid hormone in your body if your thyroid gland produces too much thyroid hormone and you are taking medication to suppress thyroid function.
  • To check how well your thyroid is working.
  • As a starting dose in children to replace of thyroid hormone when treating
  • an underactive thyroid.
  • As a low starting dose in older patients, patients with cardiovascular diseases and patients with severe or chronic hypothyroidism.


Always take this medicine exactly as your doctor or pharmacist has told you.

This medicine is for oral use. Take the daily dose in one single intake on an empty stomach (at least half an hour before breakfast), preferably with a small amount of liquid, for example half a glass of water.

Babies can be given the entire daily dose of this medication at least half an hour before the first meal of the day. Dissolve the tablets in some water. The dissolved medicine should be taken with liquid. Use the mixture right away and do not store it to use later.

Tell your doctor if your diet includes soy products, especially if you are going to eat or drink more or less of them. Soy can prevent optimal absorption of your medication, resulting in inconsistent medication effects. Therefore, it may be necessary to adjust the dose.


Your dose will be decided by your doctor. Your doctor will usually start treatment with the lowest possible dose and may increase the dose you take every two to four weeks until your final dose is reached. Check the package leaflet for dosage recommendations.


This medicine does not affect your reaction time or interact with alcohol.

If you take more or less Levothyroxine than you should

If you have taken more tablets than the prescribed dosage, tell your doctor immediately. Signs of an overdose may include racing heartbeat, anxiety, agitation, restlessness or involuntary muscle contractions. The use of Levothyroxine in patients with epilepsy or susceptibility to psychosis could cause their condition to get worse. Contact your doctor if you have this reaction.

If you forget to take a dose, do NOT take a double dose to make up for it. Just skip the dose and resume your regular schedule.

When not to use Levothyroxine

Levothyroxine is not suitable for everyone. Do not take this medicine if:

  • You are allergic to any of the ingredients in this medicine (see section ‘What Levothyroxine contains').
  • You have a condition that is not being treated, such as a condition affecting the adrenal glands or pituitary gland, or a condition where your thyroid gland releases high levels of thyroid hormone (hyperthyroidism).
  • You have sudden heart problems (heart attack or inflammation of the heart muscle).

When should this medicine be used with extreme caution?

Consult a doctor on the use of Levothyroxine if:

  • You suffer from heart problems such as angina pectoris, heart failure or heart rhythm disturbances.
  • You have high blood pressure or hardening of the arteries (atherosclerosis).
  • You are menopausal or postmenopausal. The use of this medicine increases your risk of osteoporosis.
  • You are switching from one levothyroxine medication to another.
  • You are taking orlistat for weight loss. Consult a doctor before you start using orlistat, or if you want to adjust or discontinue the use of orlistat.
  • You are experiencing symptoms of psychosis.
  • Your adrenal glands do not produce adequate amounts of hormones (adrenal insufficiency).

The use of this medicine will need to be monitored or the dose may need to be adjusted.

For more warnings about the use of Levothyroxine, please see the package leaflet.

Pregnancy and breastfeeding

If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

This medicine can be used during pregnancy but should NOT be used in combination with thyreostatic medicines (medicines used to inhibit overactive thyroid function). Your doctor may decide to adjust the dosage, if necessary. If you get pregnant while taking this medicine, contact your doctor.

There is no evidence that the use of this medicine by breastfeeding women is harmful to infants with a normally functioning thyroid gland. If you are breastfeeding, you should NOT use this medicine in combination with thyreostatic medicines (medicines used to inhibit overactive thyroid function).

Other medicines and Levothyroxine

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. Many medicines affect the way Levothyroxine works. The effects of other drugs may also be affected by Levothyroxine. Medicines known to interact with Levothyroxine Accord include:

  • Medicines used to treat diabetes.
  • Certain anticoagulants (coumarin derivates).
  • Bile acid sequestrants and medicines used to treat high level of fat in the blood (e.g., cholestyramine and colestipol). Take Levothyroxine 4-5 hours before taking these medicines.
  • Medicines used to reduce excess stomach acid, sucralfate (used to treat and prevent stomach and duodenal ulcers) and medicines containing aluminium compounds, iron or calcium carbonate. Take Levothyroxine two hours before taking these medicines.
  • Propylthiouracil (used to manage hyperthyroidism which is due to an overactive thyroid gland).
  • Glucocorticoids (used to treat allergies and inflammation).
  • Beta blockers (used to treat high blood pressure and heart problems).
  • Sertraline (used to treat depression).
  • Chloroquine or proguanil (used to prevent and treat malaria).
  • Medicines that activate certain liver enzymes, such as barbiturates or carbamazepine.
  • Oestrogen-containing medicines for hormone replacement therapy (HRT) and contraception.
  • Sevelamer (used to control kidney disease).
  • Tyrosine kinase inhibitors (used to treat cancer and inflammation).
  • Orlistat (used to treat obesity).
  • Salicylates (used to treat pain, fever and inflammation).
  • Dicumarol (anticoagulant used to prevent or treat blood clots).
  • High dose (250 mg) furosemide (diuretic).
  • Clofibrate (lipid-lowering medicine used to control high cholesterol).
  • Ritonavir, indinavir, lopinavir (used to treat HIV infection).
  • Phenytoin (anticonvulsant medicine, used to treat epilepsy).

Tell your doctor if you are taking amiodarone (medicine used to treat and prevent an irregular heartbeat). This medicine may affect thyroid gland function.

For a list of all medicines that may interfere with the way Levothyroxine works, please see the package leaflet.

Side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them. The most commonly reported side effects of Levothyroxine include:

  • Headache.
  • Flushing, sweating.
  • Weight loss.
  • Involuntary movement of the body (tremor), restlessness.
  • Loss of consciousness accompanied by involuntary movements (convulsions).
  • Difficulty sleeping (insomnia).
  • Racing heartbeat, chest pain or tightness (angina pectoris).
  • Irregular heartbeat, pounding heartbeat (palpitations).
  • High blood pressure, heart failure, heart attack.
  • Shortage of breath.
  • Increased appetite, nausea, vomiting, diarrhoea, stomach cramps.
  • Muscle weakness and muscle cramps.
  • Fever.
  • Menstrual changes.
  • Decrease in bone density, especially in postmenopausal women who have used high doses of this medicine for long periods.
  • Overactive thyroid gland.

For more information on side effects, see the package leaflet. If you get any side effects, talk to your doctor, pharmacist or nurse.

What Levothyroxine contains

The active substance is anhydrous levothyroxine sodium. Each tablet contains 12.5, 25, 50, 75, 88, 100, 112, 125, 137, 150, 175, of 200 micrograms of levothyroxine sodium.

The other ingredients are cellulose microcrystalline, light magnesium oxide, sodium starch glycolate type A, and sodium stearyl fumarate. The tablets also contain artificial colourants. Please see the package leaflet for an overview of these substances.

The manufacturers of Levothyroxine are:

LABORATORI FUNDACIÓ DAU C/ C, 12-14 Pol. Ind. Zona Franca
Barcelona 08040


Accord Healthcare Polska Sp.z.o.o. Ul. Lutomierska 50
95-200 Pabianice


Package leaflet

Read the package leaflet before use. You can download the official package leaflet of Levothyroxine here.

Reviewed by:

Dr Wouter Mol, General practitioner Registrationnumber: BIG: 9057675501 Last checked: 30-10-2023 | Still valid

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