“The history of potency failures…indicates that Synthroid has not been reliably potent and stable.” — United States Food and Drug Administration Letter to Synthroid Manufacturer, Knoll Pharmaceuticals, April 26, 2001
“Although you claim that Synthroid has been carefully manufactured, the violations of current good manufacturing practices discussed above indicate that Knoll has not always manufactured Synthroid in accordance with current standards for pharmaceutical manufacturing.” — United States Food and Drug Administration Letter to Synthroid Manufacturer, Knoll Pharmaceuticals, April 26, 2001
A 1994 review of the testing facility found additional problems with testing of product, and another recall in 1998 took place of subpotent product.
Synthroid had sales of over 540 million in 2000 and ranked by the number of prescriptions written was the third most frequently prescribed drug in the country.
In 2001, the U.S. Food and Drug Administration (FDA) informed Abbott Laboratories that its thyroid medicine Synthroid had a “history of problems” and could not be recognized as safe and effective. The agency’s statements raised the possibility that the 40-year-old drug, which had never been officially approved for use by the FDA, would be subject to regulatory action that could, in the extreme, include removal from the market— a process that began in August 2001.
Synthroid has a long history of manufacturing problems, subpotency concerns, and stability and reliability issues, said the letter sent to Synthroid’s manufacturer from the FDA, and released to the public. The FDA’s letter was sent in response to Knoll’s request that Synthroid be permitted to be legally marketed without an approved new drug application (NDA), and instead be granted what’s known as “Generally Recognized as Safe and Effective (GRAS/E)” status. The letter indicated that Knoll had requested that the FDA also waive requirements for “adequate and well-controlled studies…”
In a fairly scathing response, the FDA officially denied Knoll’s request, meaning that Synthroid had to apply for a new drug application by August, 2001, in order to remain legally on the market.
The FDA denied the request for four key reasons:
- FDA Had the Authority to Declare Synthroid a New Drug
- Synthroid Could Not Be Generally Recognized as Safe and Effective Because it is of No Fixed Composition
- Synthroid Had a History of Problems
- Patients Need a Precise Dose of Levothyroxine Sodium
Thyroid Function: The Root of the Problem
Irrespective of the quality and safety of Synthroid (these were issues raised by the FDA), it stands to reason that thyroid hypofunction cannot be universally resolved simply by taking a synthetic thyroxine molecule. We need to consider the conversion of thyroxine to tri-iodothyronine. We need to seriously consider that thyroid hypofunction may be secondary to anterior pituitary hypofunction, infection, liver dysfunction as well as many other factors.
We need to consider that the inability to convert thyroxine to trilodothyronine may be due to adrenal cortical hyperfunction and/or excess estradiol (exogenous or endogenous). We need to consider the nutritional status, pH balance, and functional organ/gland status of all the interactions in the body.
The use of Synthroid is simply unable to address these issues adequately – just like taking aspirin does not address the root cause of chronic headaches.