Synthroid (Levothyroxine)

What is Synthroid?

Synthroid (levothyroxine) is a substitute for a hormone normally produced by thyroid gland to regulate the body's metabolism. When the thyroid gland does not produce on its own, enough of this hormone, Synthroid is given.

What is Synthroid used for?

Synthroid is used to treat an underactive thyroid (hypothyroidism).  Synthroid is also used to treat other types of thyroid disorders such as thyroiditis, thyroid nodules, certain types of goiters, and thyroid cancer.

How does Synthroid work?

Synthroid works by acting as a substitute for the body's natural thyroid.

How to use Synthroid

Synthroid should be taken in the manner prescribed by the doctor. Taking extra dose or using it for longer periods can cause problems. Synthroid is usually taken in the morning. Remember to take this medicine at the same time each day.

Take Synthroid tablet with a full glass of water. Keep a gap of at least 30 minutes between eating and taking Synthroid. Get your kidney, liver and blood tested on a regular basis.

Synthroid warnings and precautions

Avoid taking infant soy formula, walnuts, cotton seed meal, and high-fiber foods while taking Synthroid as it can lead to less absorption of Synthroid.  Before starting with the medication, tell your doctor if you have diabetes, a thyroid disorder called thyrotoxicosis, heart disease, anemia, history of blood clots, or problems with your pituitary or adrenal glands.

Taking Synthroid over longer periods of time may cause bone loss, or osteoporosis. Consult your doctor about this. Don’t change to a generic levothyroxine drug product without consulting your doctor.

What do I do if I have missed a Synthroid dose?

If you have missed your Synthroid dose you can take the missed dose as soon as you remember but do not take it if it is time for your next dose.

What do I do if I have taken a Synthroid overdose?

If you have taken a Synthroid overdose you should discontinue the use of Synthroid temporarily and seek medical attention.

Synthroid interactions

Before taking Synthroid, tell your doctor about all the prescription drugs you use. This includes minerals, vitamins, and herbal products. Avoid using lithium, amiodarone, or antidepressants along with Synthroid as the drug interaction may cause medical problems. Consult your doctor if you have received, recently, radiation therapy with iodine (such as I-131).

There are certain medicines which can be taken with Synthroid. However, these should be taken at least 4 hours before or after the use of Synthroid. These are calcium carbonate (Caltrate, Citracal, Oystercal, and others); sucralfate (Carafate); ferrous sulfate iron supplement; sodium polystyrene sulfonate (Kayexalate, Kionex, and others); cholesterol-lowering drugs like cholestyramine (Questran) and colestipol (Colestid), and antacids that contain aluminum (Amphojel, Gaviscon, Maalox, Mylanta, Riopan, Rulox, Tums, and others).

Synthroid side effects

Synthroid side effects include breathing difficulty; swelling of face, tongue, lips or throat; and other allergic reactions. If you get any of these side effects after using Synthroid, contact your doctor. Some less serious side effects of Synthroid may include mild hair loss.

Sudden headache, appetite changes, insomnia, fever, hot flashes, changes in menstrual periods and weight changes are also side effects from Synthroid.