This page contains drug information on Synthroid.
The information provided includes the following:
• what is Synthroid
• the possible side effects of Synthroid
• what happens if you miss a dose of Synthroid
• what happens if you overdose with Synthroid
• the most important information about Synthroid
• how to use Synthroid
• other drugs that may affect Synthroid
• what to avoid while using Synthroid 

Generic Name:  levothyroxine  (lee voe thye ROCK seen)
Brand Names: Eltroxin, Euthyrox, Levo-T, Levotabs, Levothroid, Levoxyl, Synthroid, Unithroid

What is the most important information I should know about synthroid?
•  It is important to take synthroid regularly to get the most benefit.
•  Do not stop taking this medication without talking to your doctor. It is important to take this medication to replace the thyroid hormone that the body is not producing. Even if you feel well, you may still need to take this medicine every day.
•  Do not change brands or change to a generic synthroid drug product without first talking to your doctor. Some synthroid products may not be interchangeable.

What is synthroid?

 •  Synthroid is a naturally occurring hormone produced by the thyroid. It is important for normal energy and metabolism. For a variety of reasons, the body may not produce enough of this hormone on its own. In these cases, synthroid is taken to replace the bodys natural thyroid hormone.
 •  Synthroid is used to treat hypothyroidism (low thyroid function). Synthroid is also used to prevent and treat goiter (growth or enlargement of the thyroid gland). Causes of goiter include hormonal imbalances, radiation, surgery, and cancer.
 •  Synthroid may also be used for purposes other than those listed in this medication guide.

What should I discuss with my healthcare provider before taking synthroid?

 •  Since thyroid hormone occurs naturally in the body, almost anyone can take this drug. In general, synthroid should not be taken if you have other hormonal problems that are not being adequately treated.
 •  Before taking this medication, tell your doctor if you have a heart disease such as coronary artery disease, hypertension, or angina. These conditions may be affected by thyroid therapy, and closer monitoring may be necessary at the start of therapy.
 •  Changes in blood sugar may occur if you have diabetes, and special monitoring may be necessary.
 •  Synthroid is in the FDA pregnancy category A. This means that synthroid is safe for use during pregnancy. It is also safe to take thyroid hormones if you are breast-feeding a baby. This drug does pass into breast milk, but it is not expected to be harmful to a nursing infant.

How should I take synthroid?

 •  Take this medication exactly as directed by your doctor. If you do not understand these directions, ask your doctor, nurse, or pharmacist to explain them to you.
 •  Take each dose with a full glass (8 ounces) of water.
 •  Take this medication at the same time each day whenever possible. Thyroid hormone is usually taken in the morning to prevent insomnia at night. Follow your doctors instructions.
 •  It is important to take synthroid regularly to get the most benefit.
 •  Do not stop taking this medication without talking to your doctor. It is important to take this medication to replace the thyroid hormone that the body is not producing. Even if you feel well, you may still need to take this medicine every day.
 •  Do not change brands or change to a generic synthroid drug product without first talking to your doctor. Some synthroid products may not be interchangeable.
 •  Your doctor may want you to have blood tests or other medical evaluations during treatment with synthroid to monitor progress and side effects.
 •  Store synthroid at room temperature away from moisture and heat.

What happens if I miss a dose?

 •  Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose. Do not take a double dose of this medication.

What happens if I overdose?

 •  Seek emergency medical treatment if an overdose is suspected.
 •  Symptoms of a synthroid overdose may include chest pain, nervousness, trouble sleeping, tremor, rapid heartbeat, nausea, headache, fever, sweating, shortness of breath, heat intolerance, irregular menses, increased appetite, decreased weight, diarrhea, and abdominal pain.

What should I avoid while taking synthroid?

 •  Do not change brands or change to a generic synthroid drug product without first talking to your doctor. Some synthroid products may not be interchangeable.

What are the possible side effects of synthroid?

 •  If you experience any of the following serious side effects, stop taking synthroid and seek emergency medical attention or contact your doctor immediately:
      • an allergic reaction (difficulty breathing closing of the throat swelling of the lips, tongue, or face or hives)
      • vomiting or
      • chest pain, irregular heartbeat, shortness of breath.
 •  Other, less serious side effects may be more likely to occur. Continue to take synthroid and talk to your doctor or try another similar medication if you experience
      • tremor, nervousness, or irritability
      • headache
      • insomnia
      • diarrhea, changes in appetite, or weight loss
      • leg cramps
      • menstrual irregularities or
      • fever, sweating, or heat sensitivity.
 •  Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What other drugs will affect synthroid?

 •  Other drugs may bind to synthroid and reduce the amount that is available in the body, making it less effective. Separate synthroid doses from the following medicines:
      • antacids that contain aluminum
      • the prescription ulcer medicine sucralfate (Carafate)
      • the cholesterol-lowering drugs cholestyramine (Questran) and colestipol (Colestid) and
      • ferrous sulfate (a type of iron supplement).
 •  Drugs other than those listed here may also interact with synthroid or affect your condition. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including vitamins, minerals, and herbal products.