Synthroid Bioequivalence Study Results Released, April 1997

April 1997 -- This week, the most well-known drug to thyroid patients in the U.S. Synthroid -- is in the limelight. It appears that Knoll Pharmaceutical, Synthroid's manufacturers, have decided to release the long-awaited results of a study they funded, looking at the bioequivalence of Synthroid -- Knoll's brand name levothyroxine -- compared to other brand names and generic levothyroxine. Seems that researchers found that there's really no difference in effectiveness, and Knoll wasn't too eager to release results that didn't support their profitable claim that Synthroid -- currently the third largest selling prescription medicine in the U.S. -- has no bioequivalent.

Bioequivalence?
According to the medical dictionaries, it means the property of having the same biological effects of that to which a medicine was compared. Come again--in English this time??? Okay, it means that the medicine studied DOES the same thing as the medicine it was compared to, even though the different brands might not be identical in terms of contents, fillers, manufacturing, etc.

While the end result of the study showed bioequivalence, that doesn't mean that each drug works the same for each person. Doctors don't like to arbitrarily switch your thyroid drug, especially if your thyroid is stabilized. But if you do switch from one drug to another, your TSH levels should be checked. And if you're not doing well on one brand or a generic, consider asking your doctor to switch you to another brand. There are many reports of people who do fine on one brand name or generic levothyroxine, but have recurring symptoms and blood levels getting out of whack when taking the same dose of another brand name or generic. Go figure!