Tirosint, Levo-T

Tirosint, Levo-T

What is levothyroxine?

Levothyroxine is a replacement for a hormone normally produced by your thyroid gland to regulate the body's energy and metabolism. Levothyroxine is given when the thyroid does not produce enough of this hormone on its own.

Levothyroxine treats hypothyroidism (low thyroid hormone). It is also used to treat or prevent goiter (enlarged thyroid gland), which can be caused by hormone imbalances, radiation treatment, surgery, or cancer.

Important information You may not be able to take levothyroxine if you have certain medical conditions.

Tell your doctor if you have an untreated or uncontrolled adrenal gland disorder, a thyroid disorder called thyrotoxicosis, or if you have any recent or current symptoms of a heart attack. levothyroxine sodium, Synthroid, Levoxyl, Levothroid, Unithroid, Advertisement SLIDESHOW Breast Cancer Therapy: Right On Target Levothyroxine should not be used to treat obesity or weight problems.

Dangerous side effects or death can occur from the misuse of levothyroxine, especially if you are taking any other weight-loss medications or appetite suppressants.

Before taking this medicine Levothyroxine should not be used to treat obesity or weight problems. Dangerous side effects or death can occur from the misuse of levothyroxine, especially if you are taking any other weight-loss medications or appetite suppressants.

Since thyroid hormone occurs naturally in the body, almost anyone can take levothyroxine. However, you may not be able to take this medication if you have certain medical conditions.

To make sure levothyroxine is safe for you, tell your doctor if you have:

a thyroid disorder called thyrotoxicosis; heart disease, coronary artery disease, or a history of blood clots; diabetes (insulin or oral diabetes medication doses may need to be changed when you start taking levothyroxine); anemia (lack of red blood cells); osteoporosis, or low bone mineral density; problems with your pituitary gland; any food or drug allergies; an untreated or uncontrolled adrenal gland disorder; or if you have recently had a heart attack, or are having any symptoms of a heart attack (chest pain or heavy feeling, pain spreading to the jaw or shoulder, nausea, sweating, general ill feeling).

Tell your doctor if you have recently received radiation therapy with iodine (such as I-131).

Levothyroxine is not expected to harm an unborn baby. If you become pregnant while taking this medicine, do not stop taking the medicine without your doctor's advice. Having low thyroid hormone levels during pregnancy could harm both mother and baby. Your dose needs may be different during pregnancy.

Levothyroxine can pass into breast milk, but it is not expected to be harmful to a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby. Your dose needs may be different while you are nursing.

How should I take levothyroxine? Take levothyroxine exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Do not share this medication with another person, even if they have the same symptoms you have.

Levothyroxine works best if you take it on an empty stomach, at least 30 minutes before breakfast. Follow your doctor's dosing instructions and try to take the medicine at the same time each day.

It is very important to take Levoxyl with a full glass (8 ounces) of water. The Levoxyl tablet can dissolve very quickly and swell in the throat, possibly causing choking or gagging.

While using levothyroxine, you may need frequent medical tests.

Tell any doctor or dentist who treats you that you are using levothyroxine.

Store at room temperature away from moisture and heat.

It may take several weeks before your body starts to respond to levothyroxine. Keep using this medicine even if you feel well. You may need to use this medicine for the rest of your life to replace the thyroid hormone your body cannot produce.

See also: Dosage Information (in more detail)

What happens if I miss a dose? Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose? Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include headache, leg cramps, tremors, feeling nervous or irritable, chest pain, shortness of breath, and fast or pounding heartbeats.

What should I avoid? Certain medicines can make levothyroxine less effective if taken at the same time. If you use any of the following drugs, avoid taking them within 4 hours before or 4 hours after you take levothyroxine:

calcium carbonate (Alka-Mints, Calcium Oyster Shell, Caltrate, Os-Cal, Oyster Shell Calcium, Rolaids Soft Chew, Tums, and others); cholestyramine, colestipol; ferrous sulfate iron supplement; sucralfate; sodium polystyrene sulfonate (Kalexate, Kayexalate, Kionex); or antacids that contain aluminum or magnesium - Acid Gone, Gaviscon, Maalox, Milk of Magnesia, Mintox, Mylanta, Pepcid Complete, and others).

Avoid the following food products, which can make your body absorb less levothyroxine: infant soy formula, cotton seed meal, walnuts, and high-fiber foods.

Levothyroxine side effects Get emergency medical help if you have any signs of an allergic reaction to levothyroxine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

fast or irregular heart rate; fever, hot flashes, sweating; sleep problems (insomnia); changes in your menstrual periods; or vomiting, diarrhea, appetite changes, weight changes. Common levothyroxine side effects may include mild hair loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect levothyroxine? Many other medicines can be affected by your thyroid hormone levels. Other medicine may also increase or decrease the effects of levothyroxine.

Many drugs can interact with levothyroxine and not all possible interactions are listed in this medication guide.

Tell your doctor about all medications you use, start using, or stop using during your treatment with this medicine. This includes prescription, over-the-counter, vitamin, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.

GENERIC NAME: levothyroxine sodium

BRAND NAME: Synthroid, Levoxyl, Levothroid, Unithroid, Tirosint, Levo-T (discontinued brand) DRUG CLASS AND MECHANISM: Levothyroxine is a synthetic (man-made) version of the principle thyroid hormone, thyroxine (T4) that is made and released by the thyroid gland. Thyroid hormone increases the metabolic rate of cells of all tissues in the body.

In the fetus and newborn, thyroid hormone is important for the growth and development of all tissues including bones and the brain. In adults, thyroid hormone helps to maintain brain function, utilization of food, and body temperature, among other effects.

PRESCRIBED FOR: Levothyroxine is approved to treat hypothyroidism to suppress thyroid hormone release from cancerous thyroid nodules, and to prevent growth of goiters.

In addition, Synthroid, Levoxyl and Levothyroid also are prescribed with anti-thyroid drugs, for example methimazole (Tapazole), to manage thyrotoxicosis (high thyroid hormone levels due to over-activity of the thyroid gland). Thyrotoxicosis may result in the growth of goiters and/or result in hypothyroidism.

SIDE EFFECTS: Levothyroxine therapy usually is well-tolerated. If symptoms occur, they often are due to toxic levels of thyroid hormone, and the symptoms are those of hyperthyroidism.

The most commonly reported side effects include:

chest pain, increased heart rate or pulse rate, excessive sweating, heat intolerance, nervousness, headache, insomnia, diarrhea, vomiting, weight loss, or fever. Women may experience irregular menstrual cycles.

Uses Levothyroxine is used to treat an underactive thyroid (hypothyroidism). It replaces or provides more thyroid hormone, which is normally produced by the thyroid gland. Low thyroid hormone levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery.

Having enough thyroid hormone is important for maintaining normal mental and physical activity. In children, having enough thyroid hormone is important for normal mental and physical development.

This medication is also used to treat other types of thyroid disorders (such as certain types of goiters, thyroid cancer).

This medication should not be used to treat infertility unless it is caused by low thyroid hormone levels.

How to use levothyroxine Take this medication by mouth as directed by your doctor, usually once daily on an empty stomach, 30 minutes to 1 hour before breakfast. Take this medication with a full glass of water unless your doctor directs you otherwise.

If you are taking the capsule form of this medication, swallow it whole. Do not split, crush, or chew. People who cannot swallow the capsule whole (such as infants or small children) should use the tablet form of the medication.

For infants or children who cannot swallow whole tablets, crush the tablet and mix in 1 to 2 teaspoons (5 to 10 milliliters) of water, and give using a spoon or dropper right away. Do not prepare a supply in advance or mix the tablet in soy infant formula. Consult your pharmacist for more information.

Dosage is based on your age, weight, medical condition, laboratory test results, and response to treatment.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day.

Do not stop taking this medication without first consulting with your doctor. Thyroid replacement treatment is usually taken for life.

There are different brands of levothyroxine available. Do not change brands without first consulting your doctor or pharmacist.

Certain medications (such as cholestyramine, colestipol, colesevelam, antacids, sucralfate, simethicone, iron, sodium polystyrene sulfonate, calcium supplements, orlistat, sevelamer, among others) can decrease the amount of thyroid hormone that is absorbed by your body. If you are taking any of these drugs, separate them from this medication by at least 4 hours.

Symptoms of low thyroid hormone levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heartbeat, or sensitivity to cold. Tell your doctor if your condition worsens or persists after several weeks of taking this medication.

WHAT IS SYNTHROID? Synthroid is a prescription medication that can help treat hypothyroidism. The active ingredient in Synthroid is called levothyroxine sodium. Synthroid can help restore thyroid hormone balance. It is a man-made thyroid hormone identical to thyroxine, the hormone that’s naturally made by the thyroid gland. Generally, thyroid replacement medication is to be taken for life.

Thyroid hormones, including SYNTHROID, should not be used for the treatment of obesity or weight loss. Large doses of thyroid hormone, especially when used with certain medicines that reduce appetite, can result in serious and even life-threatening effects.

Do not use SYNTHROID if you have hyperthyroidism or over-active thyroid, uncorrected adrenal problems, are having symptoms of a heart attack, or are allergic to any of its ingredients.

Talk to your doctor about any medication and food allergies, all medications you are taking, pregnancy plans, and all medical conditions you may have, especially heart disease, diabetes, clotting disorders, and adrenal or pituitary gland problems.

Tell your doctor if you experience rapid or irregular heartbeat, chest pain, shortness of breath, leg cramps, headache, nervousness, irritability, sleeplessness, tremors, change in appetite, weight gain or loss, vomiting, diarrhea, excessive sweating, heat intolerance, fever, changes in menstrual periods, hives or skin rash, or any other unusual medical event.

This article is about levothyroxine as a pharmaceutical drug. For its role as a hormone, see Thyroid hormone.

Levothyroxine Levothyroxine 200.svg Levothyroxine 3D ball.png Names IUPAC name (S)-2-Amino-3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]propanoic acid Other names 3,5, 3', 5'-Tetraiodo-L-thyronine Identifiers CAS Number 51-48-9 Yes ChEBI CHEBI:18332 Yes ChEMBL ChEMBL1624 Yes ChemSpider 5614 Yes DrugBank DB00451 Yes IUPHAR/BPS 2635 Jmol 3D model Interactive image MeSH Thyroxine PubChem 5819 UNII Q51BO43MG4 InChI[show] SMILES[show] Properties Chemical formula C15H11I4NO4 Molar mass 776.87 g·mol−1 Melting point 231 to 233 °C (448 to 451 °F; 504 to 506 K) [2] Solubility in water Slightly soluble (0.105 mg·l−1 at 25 °C)[1] Pharmacology ATC code H03AA01 (WHO) Legal status ℞ (Prescription only) Pregnancy category US: A (No risk in human studies) Routes of administration Oral, intravenous Pharmacokinetics: Bioavailability ~100% Metabolism Mainly in liver, kidneys, brain and muscles Biological half-life ca.

7 days (in hyperthyroidism 3-4 days, in hypothyroidism 9-10 days) Excretion Through feces and urine Hazards S-phrases S22-S24/25 Related compounds Related compounds Triiodothyronine (tri-iodated) Thyronine (without iodine) Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is Yes ?) Infobox references Levothyroxine, also known as L-thyroxine, is a synthetic thyroid hormone that is chemically identical to thyroxine (T4), which is naturally secreted by the follicular cells of the thyroid gland.

It is used to treat thyroid hormone deficiency, and occasionally to prevent the recurrence of thyroid cancer. Like its naturally secreted counterpart, levothyroxine is a chiral compound in the L-form.

The related drug dextrothyroxine (D-thyroxine) was used in the past as a treatment for hypercholesterolemia (elevated cholesterol levels) but was withdrawn due to cardiac side effects.

It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.[3]