US Brand names

1. Levothroid
2. Levoxyl
3. Synthroid
4. Tirosint
5. Unithroid

Canadian Brand names

1. Eltroxin
2. Synthroid 

Levothyroxine is a synthetic version of the hormone Thyroxine which is normally produced by your thyroid gland to regulate the body’s energy and metabolism. Levothyroxine is given when the thyroid does not produce enough Thyroxine on its own.

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

Levothyroxine (Synthroid) may also be used for purposes not listed in this medication guide.

What are the available dosage forms and strengths?

Tablet:

• 25mcg
• 50mcg
• 75mcg
• 88mcg
• 100mcg
• 112mcg
• 125mcg
• 137mcg
• 150mcg
• 175mcg
• 200mcg
• 300mcg

How should you take Levothyroxine (Synthroid)? 

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use exactly as directed by your healthcare provider.

Levothyroxine works best if you take it on an empty stomach, 30 to 60 minutes before breakfast. Follow your doctor’s dosing instructions and try to take the medicine at the same time each day.

Swallow the tablet or capsule whole, with a full glass (8 ounces) of water. The levothyroxine tablet may dissolve very quickly and could swell in your throat.

Levothyroxine doses are based on weight in children. Your dose needs may change if you gain or lose weight.

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 levothyroxine for the rest of your life.

You may need frequent medical tests. Tell any doctor, dentist, or surgeon who treats you that you are using levothyroxine.

If you miss a dose, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Store at room temperature away from moisture, heat, and light.

Who should not take Levothyroxine (Synthroid)?

Anyone who is allergic to levothyroxine or any of the other ingredients contained in the medication; should not take levothyroxine.

If you have certain medical conditions, you may not be able to take levothyroxine.  These include an overactive thyroid gland or any condition which affects your adrenal glands.

What to avoid while taking Levothyroxine (Synthroid)?

Certain foods affect your body’s absorption of levothyroxine.  Avoid the following food products, which can make your body, absorb less levothyroxine: grapefruit juice, infant soy formula, soybean flour, cotton seed meal, walnuts, and high-fiber foods.

What should I tell my healthcare provider before using Levothyroxine (Synthroid)? 

Tell your doctor if you have or ever had:

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

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

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 weight-loss medications or appetite suppressants.

If you become pregnant while taking levothyroxine, 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.

Tell your doctor if you are breast-feeding. Your dose needs may be different while you are nursing.

Do not give this medicine to a child without medical advice. 

What are the possible side effects of Levothyroxine (Synthroid)?

Stop taking the tablets and seek emergency medical help if you have signs of an allergic reaction: swelling of the face, tongue, difficulty breathing, sever itch,ing of the skin with raised lumps, sensitivity to the sun, or a general feeling of being unwell.

Call your doctor at once if you have:

• fast or pounding heartbeat;
• pain or burning when you urinate or difficulty doing so;
• severe headache, blurred vision or confusion;
• pounding in your neck or ears, nosebleed, anxiety;
• severe chest pain, shortness of breath, irregular heartbeats.

Common side effects may include:

• increased blood pressure;
• headache, dizziness;
• cold symptoms such as stuffy nose, sneezing, sore throat; or
• constipation, diarrhea.
• dry mouth; or.
• back pain, joint pain, leg cramps.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

What other drugs interact with Levothyroxine (Synthroid)?

Tell your doctor about all your other medicines, especially:

• calcium carbonate (Alka-Mints, Caltrate, Os-Cal, Oyster Shell Calcium, Rolaids Soft Chew, Tums, and others);
• cholestyramine, colesevelam, colestipol;
• corticosteroids such as hydrocortisone and prednisolone; 
• blood thinners such as warfarin (Coumadin);
• ferrous sulfate iron supplement;
• estrogen containing medication for hormone replacement therapy and contraception;
• sucralfate;
• sodium polystyrene sulfonate (Kalexate, Kayexalate, Kionex);
• stomach acid reducers–esomeprazole, lansoprazole, omeprazole, rabeprazole, Nexium, Prilosec, Prevacid, Protonix, Zegerid, and others; or
• antacids that contain aluminum or magnesium–Gaviscon, Maalox, Milk of Magnesia, Mintox, Mylanta, PepcidComplete, and others.

This list is not complete. Other drugs may affect this medication, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Where can I get more information about Levothyroxine (Synthroid)?

If you have any questions about buying discount Levothyroxine (Synthroid) or any other prescription products online, you can contact us.