The US Food and Drug Administration (FDA) has told Abbott Laboratories that its thyroid medicine Synthroid has a "history of problems" and cannot be recognized as safe and effective.

The agency's statements raise the possibility that the 40-year-old drug, which has never been officially approved for use by the FDA, will be subject to regulatory action that could, in the extreme, include removal from the market -- a process that could begin as early as August.

The FDA said 4 years ago that makers of thyroid drugs like Synthroid needed to get FDA approval to continue marketing them, the report noted. Abbott, which acquired Synthroid's maker earlier this year, has said it will submit an application to the agency detailing the drug's safety and efficacy and that it is confident the drug will be allowed to stay on the market, the paper said.

Synthroid had sales of $541.3 million in 2000 and, ranked by number of prescriptions written, was the third most frequently prescribed drug in the country.

But a spokesperson for the FDA said the regulatory notices the agency has published on Synthroid and its competitors "don't include a provision" related to simply submitting an application by the August 14 deadline, the paper noted.

People are going from hypothyroidism to hyperthyroidism every time they refill their prescriptions. Mary Shomon receives hundreds of e-mails a week from patients experiencing problems with their drugs. Patients "can swing from feeling like they are having a heart attack to feeling lethargic and experiencing weight gain," she said.

Further, she said, people who get a bad batch of the drug may not ever know it, because their symptoms aren't properly diagnosed. "In many cases, a doctor might say your last test results were normal, so it's not your thyroid," said Ms. Shomon, who has been an outspoken critic of some of the practices of Synthroid's owners. "He might say, 'Get some more sleep' or 'Don't eat so much.'

The FDA has not decided what it will do if the deadline comes and goes before the drug receives approval, the paper said, but the agency would not rule out asking for the drug's removal, as it believes there are two other marketed drugs in Synthroid's class that could fill any void.

Wall Street Journal June 1, 2001

Dr. Mercola's Comments:

Mary Shomon, the thyroid expert guide at About.com alerted us to this issue well over a month ago and I reported on her findings in April. Synthroid is not intrinsically harmful, but they just never proved their product to the FDA and it really does appear now that it will be taken off the market. Unithroid and Levoxyl are both currently approved under the new guidelines though (Levoxyl is far less expensive). Hopefully many will use this transition to consider switching to Armour thyroid that is generally far more effective than synthetic thyroids. Millions of women are currently undiagnosed with thyroid problems. However this does not mean that all these women need thyroid hormone replacement. But it does suggest that they would benefit from visiting a natural medicine doctor who could help them determine the cause of their thyroid impairment. This is usually related to adrenal impairment which is frequently diminished from stress issues. Related Articles: If Synthroid is Safe and Effective, Why Won't It Apply for FDA Approval Like its Competitors? NEJM Study Proves Armour Thyroid Better Than Synthroid