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All About Thyroid Drugs


Updated: December 18, 2007

by Mary J. Shomon

When it comes to thyroid drugs, it's important to know more about the pills that -- in many cases -- you will take for the rest of your life to treat your thyroid condition. For comprehensive information about thyroid drugs, access the:


Generic Thyroid Drug Names
Levothyroxine /L-thyroxine | Liothyronine | Liotrix | Methimazole | Propylthiouracil / PTU | Natural Thyroid | Thyrotropin alfa

Thyroid Drug Manufacturers
Forest Pharmaceuticals | Genzyme | Jones Pharma | Western Research Laboratories

Thyroid Drugs Brand Names
Armour Thyroid | Cytomel | Levothroid | Levoxyl | Naturethroid | Synthroid | Tapazole | Thyrogen | Thyrolar | Unithroid | Westhroid

Frequently Asked Questions
With Food or Empty Stomach?
High Fiber Diet?
Iodine & Kelp?
"Goitrogenic" Foods Like Brussels Sprouts?
Calcium / Calcium-Fortified Juice?
Cold Medicines?
Vitamins with Iron?
Breastfeeding & Thyroid/Antithyroid Drugs?
10 Ways to Remember Your Pills?
How To Take Thyroid Medication

To get you started, here's an overview of general information about thyroid drugs.

Thyroid Hormone Replacement Drugs

When your thyroid is either underactive, non-functioning, or has been all or in part surgically removed, you are considered hypothyroid. The conventional treatment for hypothyroidism is thyroid hormone replacement -- basically, taking a prescription a drug that acts similarly in the body to the human hormone thyroxine that the thyroid would normally produce.

Levothyroxine/Synthetic T4

The vast majority of doctors prescribe the synthetic drug known as levothyroxine for thyroid hormone replacement. The most commonly known brand of levothyroxine is Synthroid. There's also Levoxyl, Levothroid, Unithroid, and many brands outside the U.S. In addition, there are "generic" versions of the T4 drugs, but many doctors do not recommend them. Studies have shown the brand name levothyroxine drugs in the U.S. to be bioqeuivalent, meaning that they accomplish the same thing from a medical standpoint Different brands, however, have different fillers, and a small number of patients apparently are allergic to the fillers in one versus another. Levothyroxine provides a synthetic version of one hormone, thyroxine, known as T4. Some people with hypothyroidism find that levothyroxine therapy is sufficient treatment for their hypothyroidism.

Liothyronine/Synthetic T3

Some doctors treat hypothyroidism using levothyroxine, plus an additional drug, liothyronine (brand name, Cytomel), or prescribe it in a time released compounded version. Liothyronine is a synthetic version of triiodothyronine, abbreviated as T3, the active thyroid hormone in the body. In a person with normal health and thyroid function, the thyroid produces mainly T4 and some T3, and the T4 is converted to T3, which is then the active hormone used by the body's cells. Some doctors and endocrinologists use supplemental T3. This was supported in research featured in the New England Journal of Medicine, but some researchers in 2003 have also claimed it to be ineffective. There is still a belief by some practitioners that patients do not need T3, because they will convert T4 into the T3 the body needs. The alternative medical community believes that impaired conversion of T4 to T3 may create a deficiency in T3 that warrants direct T3 supplementation.

Liotrix / Synthetic T4/T3 Combination

The synthetic T4/T3 combination drug is liotrix, brand name Thyrolar. This drug is not very regularly prescribed, but is preferred by some physicians who wish to provide both T4 and T3, but prefer a synthetic drug.

Natural Thyroid

Natural thyroid is dessicated thyroid, derived from the gland of pigs. It was the standard thyroid drug until levothyroxine came on the market in the second half of the 20th century. Some doctors, more often osteopaths, naturopaths, and holistics M.D.s, are in favor of these natural drugs, because they believe that since the drug contains a full spectrum of thyroid hormones, beyond just the T4 and T3, it most closely mimics the human thyroid hormone. The most popular brand of natural thyroid is Armour thyroid.

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