Euthyrox (levothyroxine) is taken once a day on an empty stomach with a full glass of water, 30 to 60 minutes before the first meal, coffee, or any other medicine, and at the same time every day [1]. Keep it at least 4 hours apart from calcium and iron [2]. TSH is checked 6 to 8 weeks after starting treatment or changing the dose [3].
What Is Euthyrox and Why Is It Prescribed?
Euthyrox is a brand name for levothyroxine, a thyroid hormone that replaces the hormone your body normally produces [2]. It is mainly prescribed for hypothyroidism, a condition in which the thyroid gland does not produce enough hormone to meet the body's needs [3]. The most common causes are Hashimoto's thyroiditis, an autoimmune disease, followed by surgical removal of all or part of the gland and radioactive iodine treatment [3].
The medicine is also used alongside surgery and radioactive iodine to treat thyroid cancer [2]. Doctors sometimes prescribe it in other situations, such as subclinical hypothyroidism, a decision in which the doctor weighs the benefits against the burden for each individual patient.
Symptoms of hypothyroidism may include fatigue, weight gain, and low mood [1], as well as intolerance to cold, constipation, and dry skin [3]. The medicine controls hypothyroidism but does not cure it, so the patient continues taking it even when they feel better, and should not stop without consulting their doctor [2]. Most patients need it for life [1]. You can find more details in this frequently asked question.
How Should Euthyrox Be Taken Correctly?
The correct method is simple, but sticking to its details is what keeps hormone levels in the blood under control:
- Once a day, at the same time every day as much as possible [1].
- On an empty stomach before the first meal, or before any drink containing caffeine such as tea or coffee, or before any other medicine, by 30 to 60 minutes [1].
- With a full glass of water. Tablets may stick in the throat, cause choking, or cause nausea if taken with only a small amount of water [2].
- Follow the leaflet and the prescription, and ask your pharmacist or doctor if you are not sure [1].
What About the Dose?
The usual dose set by the doctor depends on the TSH level, your other illnesses, and your age [1]. Doctors often start with a low dose and increase it gradually until reaching the appropriate dose [1][2]. Do not increase or decrease the dose on your own, and do not take it more than once a day [2].
The Winning Trio: Timing, Routine, and Brand
Choose a fixed time, a fixed routine (empty stomach and water), and a fixed brand. This is what makes your test results comparable from one time to the next.
For a Child or Someone Who Cannot Swallow the Tablet
The tablet can be crushed and mixed with one or two teaspoons (5 to 10 mL) of water only, then given immediately with a spoon or dropper, without storing it. It should not be mixed with food or with soy-based infant formula [2]. The child's dose depends on weight and is set by a doctor's prescription or the pharmacist's guidance.
Why Is Euthyrox Taken Before Breakfast on an Empty Stomach?
Some foods and drinks affect how levothyroxine works [1]. The practical logic is that food and supplements may reduce how much of the medicine the body absorbs, so the hormone level in the blood changes from day to day. A medicine taken on an empty stomach and separately from other things gives a more stable level.
Coffee and tea specifically should come after the medicine, not with it: take the tablet first, then wait about an hour before your coffee. Our sources state 30 to 60 minutes [1], and the ClinicsJo drug guide prefers at least one hour for coffee and soy.
A practical method: keep the medicine and a glass of water beside your bed, take it as soon as you wake up, then get on with your morning routine before breakfast. If you take other medicines in the morning, ask your doctor or pharmacist to arrange their timing so that none of them clashes with Euthyrox [1].
What Interferes With Euthyrox?
Tell your doctor and pharmacist about every medicine, herb, vitamin, and supplement you take, because some of them may not be compatible with levothyroxine [1]. The following table summarizes the most common interactions:
| Substance or Medicine | What You Need to Know |
|---|---|
| Calcium (such as calcium carbonate tablets) and iron | Taken at least 4 hours before or after levothyroxine [2] |
| Antacids and treatments for indigestion | May interact with the medicine; ask your pharmacist about the appropriate spacing [1][2] |
| Omeprazole and similar drugs (proton pump inhibitors) | May interact with the medicine [1][2], and the doctor monitors TSH when they are used |
| Coffee and tea | Take the medicine 30 to 60 minutes before them [1] |
| Soy, walnuts, and dietary fiber | May affect how the medicine works, so consult your doctor about them [2] |
| Cholestyramine, colesevelam, and colestipol (cholesterol- and phosphate-lowering drugs) | Taken at least 4 hours after levothyroxine [2] |
| Epilepsy drugs such as carbamazepine | May not be compatible with the medicine [1], and they speed up its breakdown in the body, so the required dose may change |
| St John's wort | A herbal supplement that may not be compatible with the medicine [1] |
| Biotin (vitamin B7) | May affect thyroid test results, so tell your doctor before testing [1] |
There are other interactions: estrogen and birth control pills increase the body's need for the hormone, and warfarin's effect becomes stronger with levothyroxine, as explained in the ClinicsJo drug guide. Sources also state that antidepressants such as sertraline, beta-blockers, digoxin, and drugs such as semaglutide may not be compatible with it [1], as well as aspirin and anti-inflammatory painkillers such as ibuprofen [2]. Do not start any of them without consulting your doctor. The sources confirm that large doses of levothyroxine combined with amphetamine stimulants may cause serious problems [2].
Can You Switch Brands or Miss a Dose?
Switching Brands
Do not switch brands without speaking to your doctor or pharmacist, since each brand contains a slightly different amount of the medicine [2]. Switching between manufacturers slightly changes absorption, which is why TSH is rechecked after the switch, as recommended by the ClinicsJo drug guide. Medicine and its prices in Jordan are regulated by the Jordan Food and Drug Administration (JFDA). If the alternative available at your pharmacy differs from your usual box, inform your doctor so they can decide whether additional testing is needed.
Learn both the brand name and the generic name of your medicine [2], and keep a written list of everything you take to show at every visit [2].
If You Miss a Dose
Take it when you remember, unless the next dose is close, in which case skip the missed one and return to your usual schedule. Do not double the dose to make up for what you missed [1][2]. If the missed dose was your child's, ask your doctor or pharmacist [1].
When Should TSH Be Checked After Adjusting the Euthyrox Dose?
Blood results guide the dose, not symptoms alone. The usual follow-up schedule, as presented by MedlinePlus, is:
- About 6 to 8 weeks after starting the medicine: a blood test for thyroid hormone levels, after which the doctor adjusts the dose if needed [3].
- After every dose adjustment: a new test [3].
- Once the dose is stable: a test about every 6 months, then once a year [3].
It may take several weeks before you notice a change in your symptoms [2], so do not judge the dose after one week. Learn what the numbers mean in our article on comprehensive thyroid tests and in our explanation of thyroid hormones (TSH and T4). And do not forget your lab and doctor appointments, as they are part of the treatment [2].
How Do I Know If My Euthyrox Dose Is Too High or Too Low?
Signs of an Overdose
Most side effects occur when the dose is higher than needed, and they often improve when the dose is adjusted [1]. Among the most common are insomnia, headache, anxiety, sweating, and hair loss [1], as well as nausea and diarrhea [1]. MedlinePlus also mentions palpitations, rapid pulse, tremor, nervousness, shortness of breath, and heavy sweating [2]. In the long term, osteoporosis and atrial fibrillation may appear, especially in older adults, as the drug guide notes.
These symptoms resemble those of hyperthyroidism, and here the cause is excess hormone in the blood. Tell your doctor, and do not stop the medicine on your own, as stopping suddenly is not the solution [1].
Signs of an Underdose
Hypothyroidism symptoms return: fatigue, weight gain, and low mood [1], along with sensitivity to cold, constipation, and dry skin [3]. The final assessment is made by checking TSH, not by symptoms alone.
Levothyroxine Is Not a Weight-Loss Drug
MedlinePlus explicitly warns against using it alone or with other treatments to treat obesity or lose weight, because large doses may cause serious, life-threatening problems [2].
Euthyrox in Pregnancy, Breastfeeding, and With Other Conditions
Pregnancy: Tell your doctor if you are pregnant or planning to become pregnant. Levothyroxine can be taken during pregnancy when needed, and more frequent blood tests may be required to adjust the dose [1]. According to the ClinicsJo drug guide, the need for the medicine may rise by 30 to 50% during pregnancy, so do not wait for your regular follow-up appointment. Untreated hypothyroidism in pregnancy may cause preterm birth, high blood pressure, and miscarriage, and may slow fetal growth [3]. Read more in our article on thyroid disorders in pregnancy.
Breastfeeding: The medicine can usually be taken while breastfeeding, but check with your doctor or pharmacist first [1].
Other conditions: The medicine may not suit people with hyperthyroidism or an adrenal gland disorder, and diabetes and heart disease require special care [1]. MedlinePlus also lists osteoporosis, kidney and liver diseases, and difficulty swallowing [2]. In adrenal insufficiency, cortisol is corrected first. In older adults and patients with heart disease, the doctor starts with small doses and increases them slowly. If you have Hashimoto's thyroiditis, you may be sensitive to iodine, so ask your doctor which foods and supplements to avoid [3].
Before any surgery, even dental surgery, tell the doctor that you take levothyroxine [2].
When Should You See a Doctor, and When Should You Go to the Emergency Room?
See Your Doctor or Pharmacist in These Cases
- Any side effects that bother you or do not go away [1].
- Persistent hypothyroidism symptoms despite taking the medicine as prescribed.
- Pregnancy or planning for pregnancy, or starting a new medicine or supplement.
- Switching brands or frequently missing doses.
- Taking more than the prescribed dose: a single extra dose rarely causes a problem, but seek advice because it can sometimes be dangerous [1].
Call 911 or Go to the Nearest Emergency Room If You Have
- Chest pain, or a rapid or irregular pulse with shortness of breath [2].
- Confusion, loss of consciousness, or seizures [2].
- Swelling of the throat or tongue, an itchy rash, or difficulty breathing, which are signs of a severe allergic reaction [1].
- High fever with a rapid or irregular pulse, dizziness, fainting, or yellowing of the eyes and skin, which are possible signs of a thyroid storm [1].
- Taking a large dose intentionally.
Bring the medicine box or leaflet and all your other medicines [1], and do not drive yourself if you are told to go to the emergency room [1].
How Do I Find the Right Doctor to Follow Up on Euthyrox in Jordan?
The specialty responsible for thyroid follow-up is usually endocrinology and diabetes, which is available in most governorates. You can search by location, such as endocrinology and diabetes in Amman, in Irbid, or in Zarqa, and in the other governorates as well.
What should you check in the doctor's profile?
- The listed specialty and whether it matches your needs (endocrinology, or internal medicine when needed).
- The governorate, location, and ease of access, which matters because follow-up is regular.
- Working hours and the means of contact or booking, if available in the profile.
Questions to ask at the appointment:
- What is the best time to take the medicine for my routine, and how should I arrange my other medicines around it?
- When is my next TSH test, and do I need to fast before it?
- Should I stay with my current brand, and what should I do if it is unavailable?
- Which symptoms should prompt me to contact you before the appointment?
ClinicsJo lists doctors' profiles to make it easier for you to choose and get in touch, but it does not prescribe medicines or provide remote medical consultations. This article is educational and does not replace your doctor's assessment of your condition.
Frequently asked questions
Should I take Euthyrox before or after breakfast?
Before breakfast and on an empty stomach, 30 to 60 minutes before the first meal or any drink containing caffeine or any other medicine, with a glass of water. The key is to take it at the same time every day. If this routine does not suit you, ask your doctor or pharmacist about a suitable alternative.
When can I drink coffee after taking Euthyrox?
Take the medicine first, then wait before your coffee or tea. Sources recommend at least 30 to 60 minutes between the medicine and any drink containing caffeine, and the ClinicsJo drug guide prefers a full hour for coffee and soy. Coffee should be taken after the medicine, not with it.
How far apart should Euthyrox be from calcium and iron?
Calcium and iron should be taken at least 4 hours before or after levothyroxine, because they reduce its absorption. This includes calcium tablets and iron supplements. You can arrange their timing with your pharmacist, for example by taking Euthyrox in the morning and delaying the supplement until the evening.
When should TSH be tested after changing the Euthyrox dose?
Usually about 6 to 8 weeks after starting the medicine, and after every dose adjustment. Once the dose is stable, the test is done about every 6 months at first, then once a year. It may take several weeks to notice improved symptoms, so do not judge the dose before then.
Can I switch Euthyrox to another levothyroxine brand?
Do not switch without consulting your doctor or pharmacist, since each brand contains a slightly different amount of the medicine and absorption may change between manufacturers. If you must switch, inform your doctor so they can decide whether TSH needs to be retested afterward.
What should I do if I forget an Euthyrox dose?
Take the missed dose as soon as you remember, unless the next dose is due soon, in which case skip the missed one and return to your usual schedule. Do not double the dose to make up for what you missed. If you keep forgetting doses, talk to your doctor or pharmacist about a method that helps you stay consistent.
Sources and references
- Levothyroxine: a medicine for an underactive thyroid (hypothyroidism) — NHS (UK National Health Service). Accessed: 2026-10-26.
- Levothyroxine: MedlinePlus Drug Information — MedlinePlus — U.S. National Library of Medicine. Accessed: 2026-10-26.
- Hypothyroidism | Hashimoto's Disease — MedlinePlus — U.S. National Library of Medicine. Accessed: 2026-10-26.