Synthroid (Levothyroxine) is a brand-name prescription medication. The FDA has approved it for use in people with hypothyroidism (low thyroid hormone) and thyroid cancer. To regulate your body’s energy and metabolism, it replaces a hormone produced by your thyroid gland. A thyroid that produces insufficient amounts of levothyroxine is given this medication.
In cases of thyroid dysfunction, the thyroid gland produces too little thyroxine, the primary hormone it releases. Thyroxine plays a crucial role in digestion, brain development, and heart and muscle function. In Synthroid, levothyroxine sodium, like thyroxine (also called T4), functions similarly to thyroxine, allowing the body to function normally.
It is possible to have low thyroid hormone levels naturally or when the thyroid gland has been injured by radiation, medication, or surgery. In order to maintain normal mental and physical activity, thyroid hormone must be present in sufficient amounts. A healthy child’s mental and physical development depends on having enough thyroid hormone.
Well-differentiated thyroid cancer patients may also be treated with Synthroid and radioiodine therapy. Synthroid is not Armour Thyroid.
In order to buy Synthroid, you need to have a prescription. Find out if the drug is right for you by speaking with your healthcare provider
It is not recommended to use Synthroid to treat obesity or weight problems. In combination with weight-loss medications or appetite suppressants, misuse of levothyroxine can cause dangerous side effects or death.
Levothyroxine can be taken by almost anyone since thyroid hormone occurs naturally in the body. Certain medical conditions may prevent you from taking this medicine. If you have any of the following, tell your doctor:
● A disorder of the adrenal glands that is untreated or uncontrolled;
● The thyroid disorder (such as thyrotoxicosis);
● Symptoms of a heart attack (chest pain, heavy feeling, pain spreading to the jaw or shoulder, nausea, sweating, general malaise).
If you have ever had any of the following, tell your doctor before taking Synthroid:
● Nodules on the thyroid;
● The presence of heart disease, a blood clot, or a disorder of blood clotting;
● Diabetes (you may need to change your insulin or diabetes medication dose when you begin taking Synthroid);
● Disease of the kidneys;
● Anemia (deficiency of red blood cells);
● There are several causes of osteoporosis, such as:
● You may have problems with your pituitary gland;
● Allergies to food or drugs.
Consult your doctor if you recently received radiation therapy with iodine (such as I-131).
Follow the directions on your Synthroid prescription exactly. Make sure you follow all directions on your prescription label and read all medication guides and instructions. There may be times when your doctor changes your dose.
The best time to take Synthroid is 30 to 60 minutes before breakfast, on an empty stomach. Be sure to follow your doctor’s dosing instructions and take your medicine at the same time every day.
For infants and children who are unable to swallow whole tablets, Synthroid can be crushed and mixed in a small amount of water (5 to 10 mL or 1 to 2 teaspoonfuls) and immediately given by spoon or dropper. The crushed tablet/water mixture should not be stored or administered with foods that decrease absorption of levothyroxine, such as soybean-based infant formula.
Children’s levothyroxine doses are determined by their weight. A child’s dose needs may change if he or she gains or loses weight.
Synthroid may take several weeks for your body to respond. Even if you feel well, keep taking this medicine. There is a possibility that you will need to take Synthroid forever.
It is possible that you will need frequent medical tests. Synthroid should be mentioned to any doctor, dentist, or surgeon who treats you.
Keep away from moisture and heat at room temperature.
You should not share this medicine with anyone else, even if they have the same symptoms as you.
It is possible for Synthroid to cause mild or serious side effects. Synthroid can cause a number of side effects. Listed below are a few of the most common ones. All possible side effects are not included in these lists.
There is a possibility that having too much thyroid hormone in your body can cause most of the side effects of Synthroid. You may experience side effects if even a small change in your Synthroid dosage causes large changes in your hormone levels. Any side effects you’re experiencing with Synthroid should be discussed with your doctor. Your doctor may need to adjust the dosage of the drug in some cases.
During the first few months of treatment, hair loss may occur. Your body usually adjusts to this medication after a few days. Tell your doctor or pharmacist as soon as possible if this effect lasts or becomes worse.
Any serious symptoms of high thyroid hormone levels, including increased sweating, sensitivity to heat, mental/mood changes (such as nervousness, mood swings), tiredness, diarrhea, shaking (tremor), headache, shortness of breath, bone pain, easily broken bones, should be reported to your doctor right away.
In the case of chest pain, irregular heartbeat, swelling of the hands, ankles, feet, or seizures caused by high thyroid hormone levels, you should seek medical attention right away.
It is important to remember that your doctor prescribed this medication because he judged that the benefit to you outweighs the risk of side effects. There are few serious side effects associated with this medication.
It is rare for this drug to cause a very serious allergic reaction. Get medical attention right away if you notice any symptoms of a serious allergic reaction, such as: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
The following list does not include all possible side effects. Contact your doctor or pharmacist if you notice any other effects not listed above.
Call your doctor for medical advice about side effects if you live in the US. To report side effects to FDA, call 1-800-FDA-1088 or visit www.fda.gov/medwatch.
Your doctor will prescribe a Synthroid dosage based on several factors. Among them are:
● The type and severity of the condition you are treating with Synthroid
● Medications you are taking
● Possible medical conditions you may have
A low dosage is usually recommended by your doctor. After that, they will adjust it over time to find what works best for you. Your doctor will calculate the smallest dose that will achieve the desired result for you.
Synthroid may be prescribed at a lower dosage if you have certain health conditions. If you have certain heart problems, for instance, this may be the case. Consult your doctor about the best starting dose of Synthroid.
The following information describes commonly recommended or used dosages. However, follow your doctor’s instructions regarding dosage. The dosage that is right for you will be determined by your doctor.
Your thyroid hormone levels can affect many other medicines. Synthroid may also be affected by certain other medicines.
Taking certain medicines at the same time can reduce the effectiveness of levothyroxine. Avoid taking any of the following drugs within 4 hours of taking Synthroid:
● Calcium carbonate (Caltrate, Os-Cal, Oyster Shell Calcium, Rolaids Soft Chew, Tums, among others);
● Colestipol, colesevelam, cholestyramine;
● Iron supplement containing ferrous sulfate;
● Sodium sacralfate;
● Polystyrene sulfonate (Kalexate, Kayexalate, Kionex);
● Stomach acid reducers – esomeprazole, lansoprazole, omeprazole, rabeprazole, Nexium, Prilosec, Prevacid, Protonix, Zegerid, and others; or
● Gaviscon, Maalox, Milk of Magnesia, Mintox, Mylanta, Pepcid Complete, and other products with aluminum or magnesium.
Levothyroxine can interact with a wide range of drugs. Prescriptions, over-the-counter medications, vitamins, and herbal products are included in this category. This list does not include all possible interactions. Whenever you start or stop taking a medicine, tell your doctor.
Synthroid & Hypothyroidism
Hypothyroidism occurs when your body does not make enough thyroid hormones. Your metabolism is affected by these hormones. (“Metabolism” refers to all of the chemical reactions that occur in the body, including digestion, growth, and even temperature.) Synthroid restores the level of thyroid hormone in your body.
The following types of hypothyroidism can be treated with Synthroid:
● Primary (caused by thyroid problems)
● Secondary (caused by problems with your pituitary gland)
● Tertiary (resulting from hypothalamic problems)
There are two types of hypothyroidism: congenital (present at birth) and acquired (developed later in life).
Thyroid stimulating hormone (TSH) is suppressed (decreased) by Synthroid. Thyrotropin-dependent well-differentiated thyroid cancer is a form of thyroid cancer approved for this use.
TSH stimulates your thyroid to produce thyroid hormones. TSH is responsible for growing cells in your thyroid gland, including cancerous cells. T3 and T4 are the main thyroid hormones in your body. Synthroid can reduce the growth of certain types of thyroid cancer by lowering your TSH level. Check out our cancer hub for more information about thyroid cancer.
Your body produces TSH when your thyroid hormone levels are low. As a result, your thyroid produces more thyroid hormones. Synthroid, however, won’t cause low thyroid hormone levels. As a result, your body won’t need to make TSH, and your TSH level will be lower than usual.
You may be able to decrease the growth of thyroid cancer by lowering your TSH level. In conjunction with surgery and radioactive iodine treatment, Synthroid is used to suppress TSH.
Your thyroid hormone levels may decrease if you forget to take Synthroid. As a result, certain side effects may occur (see Side Effects tab).
You should take your drug at the same time each day because of this. Synthroid doses are specifically recommended to be taken on an empty stomach in the morning.
Call your doctor if you forget to take a Synthroid dose. You can ask them or their medical staff when to take your next dose.
Set a reminder on your phone to help you remember to take your medicine. It may also be helpful to use a medication timer.
Call 1-800-222-1222 for Poison Help or seek emergency medical attention.
An overdose can cause headaches, leg cramps, tremors, feeling nervous or irritable, chest pain, shortness of breath, and fast or pounding heartbeats.
Synthroid is usually continued during pregnancy if you are already taking it. Taking Synthroid during pregnancy doesn’t increase your risk of congenital anomalies (also known as birth defects) or miscarriages.
Pregnant women may be at risk of hypothyroidism, which Synthroid treats. Hypothyroidism increases some risks because your body does not produce enough thyroid hormone. Premature delivery, high blood pressure during pregnancy, and pregnancy loss are among these risks.
During pregnancy, your doctor should monitor your thyroid if you have a thyroid condition. The need for thyroid hormone may increase during pregnancy in some cases. In that case, you would need to take more Synthroid than you did before pregnancy. If needed during your pregnancy, your doctor will increase your dosage of Synthroid.
Consult your doctor about how to manage Synthroid treatment if you’re pregnant or planning to become pregnant.