Synthroid is a replacement for a hormone that is normally produced by your thyroid gland to regulate the body`s energy and metabolism. Synthroid is given when the thyroid does not produce enough of this hormone on its own. Synthroid treats hypothyroidism (low thyroid hormone). Synthroid is also used to treat or prevent goiter (enlarged thyroid gland), which can be caused by hormone imbalances, radiation treatment, surgery, or cancer. It should not be used to treat obesity or weight problems. Synthroid may also be used for other purposes not listed in this medication guide.

The health and medical information provided here is for general purposes only and is not a substitute for the expertise and judgment of your physician, or other health care professional. It should not be understood to indicate that the use of this medicine is safe, appropriate or effective for you. Always consult your health care professional before using this, or any other, drug.

Since thyroid hormone occurs naturally in the body, almost anyone can take Synthroid. You should not use this medication if you have had a heart attack, a thyroid disorder called thyrotoxicosis, or an adrenal gland problem that is not controlled by treatment.
Before taking Synthroid, tell your doctor if you have heart disease, coronary artery disease, anemia (lack of red blood cells), diabetes, problems with your pituitary or adrenal glands, or a history of blood clots.
If you use insulin or take diabetes medicine by mouth, ask your doctor if your dose needs to be changed when you start using Synthroid.
Different brands of levothyroxine may not work the same. If you get a prescription refill and your new pills look different, talk with your pharmacist or doctor.
It may take several weeks before your body starts to respond to this medication. Do not stop taking this medication suddenly. Even if you feel well, you may still need to take this medicine every day for the rest of your life to replace the thyroid hormone your body cannot produce.
There are many other medicines that can affect Synthroid. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Stop using Synthroid and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:
headache;
sleep problems (insomnia);
nervous or irritable feeling;
fever, hot flashes, sweating;
changes in your menstrual periods;
appetite changes, weight changes;
Less serious Synthroid side effects may include mild hair loss.

Take Synthroid exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
Your doctor may occasionally change your dose to make sure you get the best results from this medication.
It is very important to take Synthroid with a full glass (8 ounces) of water. The Synthroid tablet can dissolve very quickly and swell in the throat, possibly causing choking or gagging. Take this medicine on an empty stomach, 30 minutes before eating. Synthroid is usually taken in the morning. Follow your doctor`s dosing instructions and try to take this medication at the same time each day.
It may take several weeks before your body starts to respond to Synthroid. Do not stop taking this medication suddenly. Even if you feel well, you may still need to take this medicine every day for the rest of your life to replace the thyroid hormone your body cannot produce.
To be sure Synthroid is helping your condition, your blood will need to be tested often. Your liver or kidney function may also need to be tested. Visit your doctor regularly.
Tell any doctor or dentist who treats you that you are using Synthroid.
Store Synthroid at room temperature away from moisture and heat.