ask your pharmacist

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

Levothyroxine sodium products went on the market more than four decades ago. Like some other drugs that were marketed before 1962, they never received formal approval from the Food and Drug Administration (FDA). The FDA has recently required the makers of levothyroxine products to submit a New Drug Application (NDA), in order to receive formal approval. The products affected are Synthroid, Levoxyl, Levothroid, Unithroid, and all generic forms of levothyroxine sodium.

Based on this requirement, on April 15, 2002, the New Jersey Board of Pharmacy ruled that prescriptions written for Synthroid are ineligible for generic substitution. In order to have your prescription for a generic thyroid product to be filled at drugstore.com, the prescription must be written for the product (Levoxyl, Levothroid, or Unithroid) to be dispensed. Most states let pharmacists substitute a generic when appropriate and when your doctor approves it. Our pharmacy is located in New Jersey, so we only substitute generic drugs approved under New Jersey law.

Doctors 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:
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 and Comparisons, 2002.
Micromedex Healthcare Series. Micromedex, Inc., 2002.

This answer prepared 5/13/02.