ask your pharmacist

Are generic thyroid supplement drugs just as good as the brand name products?

In addition to brand name forms of levothyroxine sodium, several different generic versions are available. The Food and Drug Administration (FDA) considers most levothyroxine sodium preparations to be equivalent to each other. A pharmacist may give you a generic levothyroxine sodium product instead of a brand name product, unless your prescription specifies “no substitutions.”

The American Association of Clinical Endocrinologists (AACE), the American Thyroid Association (ATA), and the Endocrine Society (TES) have stated that there is variation in the levothyroxine sodium content among the various approved preparations with the same stated dose on the tablet. This variation may cause a problem if you switch levothyroxine sodium preparations and pharmacists usually recommend that you consistently use the same brand name or generic thyroid product.

Don't change your thyroid medicine without your doctor's knowledge. If you do change from one product to another, your doctor may want to monitor you more closely for a few months. You may need blood tests to make sure you're responding well to your particular thyroid medicine. Based on your body's response, your doctor may need to adjust your dose of medicine after you switch products.

Generic drugs can save you money. Often the generic equivalents of brand name drugs are less expensive because the manufacturer doesn't have to recoup costs of research, development, and marketing. If the cost of your thyroid medicine is a concern for you, talk with your doctor about using a generic product.

Sources:
AACE Press Releases, AACE/ATA/TES Joint Statement RE FDA approval of generic levothyroxine preparations as equivalent to branded preparations. The American Association of Clinical Endocrinologists. http://www.aace.com. Last accessed 1/31/2008.
Dong, B.J. "Bioequivalence of Generic and Brand-name Levothyroxine Products in the Treatment of Hypothyroidism," The Journal of the American Medical Association. 277 (1997).
Drug Facts and Comparisons. Facts & Comparisons, 2006.
Micromedex® Healthcare Series. Thomson Micromedex, 2006.
Thyroid Q&A, Thyroxine Preparations. The American Thyroid Assocation. http://www.thyroid.org. Last accessed 1/31/2008.

This answer prepared 5/13/2002.
This information updated 1/31/2008.