Levothyroxine

Generic name: levothyroxine (oral/injection) [ LEE-voe-thye-ROX-een ]
Brand names: Euthyrox, Levoxyl, Synthroid, Thyquidity, Tirosint, Tirosint-Sol, Unithroid
Drug class:Thyroid drugs

Medically reviewed by Sanjai Sinha, MD. Last updated on May 3, 2022.

What is levothyroxine?

Levothyroxine is a thyroid medicine that replaces a hormone normally produced by your thyroid gland to regulate the body's energy and metabolism.

Levothyroxine is used to treat hypothyroidism (low thyroid hormone). This medicine is given when your thyroid does not produce enough of this hormone on its own.

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

Warnings

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 should not be used to treat obesity or weight problems. Dangerous side effects or death can occur from the misuse of this medicine, 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 ab...