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Longtime Drug's New Troubles

Synthroid, taken by 8 million people with thyroid problems, is under FDA scrutiny.


It has been around for 46 years, is taken by some 8 million Americans and is the third-most commonly prescribed medication in the nation. Its manufacturer calls it the "quintessential old drug."

So when the Food and Drug Administration blasted the makers of Synthroid in a nine-page letter in April, reciting a long history of quality-control problems, it threw a nation of thyroid patients, their doctors and many a pharmacist into a tizzy.

The agency has threatened to remove the brand of levothyroxine from the market, saying its manufacturer has been unable to guarantee that patients were receiving proper doses--of crucial importance to those with hypothyroidism.

The letter cited five formulation changes between the years of 1981 and 1991 that could alter the effectiveness of the medication; recalls of dozens of lots of the drug; complaints from consumers or doctors questioning the potency of Synthroid tablets; and problems found during plant inspections.

The company "has not always manufactured Synthroid in accordance with current standards for pharmaceutical manufacturing," the FDA stated in the letter.

Although two of the drug's competitors have met FDA requirements proving quality, Synthroid's maker, Abbott Laboratories, has not. Since Synthroid has 60% of the hypothyroidism drug market, removal would affect millions of consumers, many of whom struggle to find the right prescription and are then advised by their physicians to avoid switching brands.

Now, under the terms of the FDA's latest directive, issued earlier this month, Abbott will soon be forced to cut distribution of Synthroid by about 5%, with further cuts pending every few months until it receives FDA approval--a situation that could eventually create shortages of the drug.

Although most federal and drug officials don't expect it to go this far, the FDA has said that any levothyroxine products still lacking approval on Aug. 14, 2003, will be withdrawn from the market.

"You have this huge population taking Synthroid who are not only finding out the drug they're on isn't FDA-approved, but that there are other options available," says Mary J. Shomon, a Maryland consumer activist on thyroid disorders. "The fact that patients are saying, 'Wait a minute, what is going on here?' indicates the lack of information."

Levothyroxine sodium is a synthetic version of a natural thyroid hormone (called T4). It is used to treat an underactive thyroid gland, a common condition called hypothyroidism, that can arise at any time of life, from birth to old age. The condition can cause weight gain, lethargy, depression, mental impairment, hoarseness, constipation, cold intolerance, dry hair and skin and a host of other symptoms.

Individuals with hypothyroidism require a precise dose of medication to remain healthy. Once they've begun treatment with levothyroxine, they typically take it for years, if not their entire lives.

But finding the proper dose is difficult. Consequently, levothyroxine is typically made in a wide range of strengths so that patients can fine-tune their doses. Getting too much of the hormone can quickly tip the scales in another direction, causing cardiac pain and arrhythmia, sleeplessness, weight loss, agitation, bone loss and other symptoms. For thyroid cancer patients and newborns with thyroid dysfunction, proper dosing is even more critical.

"What we need is data that says the [levothyroxine] drugs are made reliably," says FDA spokeswoman Laura Bradbard.

Officials for Abbott Laboratories, however, say Synthroid is a quality product and that past problems manufacturing the drug have been resolved.

Leading doctors who treat thyroid disease also downplay the significance of Synthroid's regulatory problems and have rallied behind the longtime market leader. Abbott officials mailed letters to doctors and pharmacists in June, urging that patients stay the course.

But some consumer activists say FDA approval is needed to assure consumers--who pay much more for Synthroid than most other levothyroxine brands--that they are getting a quality product.

"This is a drug that has a long history of problems," says Tim Fuller, executive director of the Gray Panthers, a consumer organization that has lobbied for pharmaceutical reform on behalf of older Americans.

It Seems 'No One Really Knew Much'

Estelle Schmitz, 85, of Malibu, was among the consumers shaken by the possibility Synthroid could be removed from the market.

"I called several pharmacists, and no one really knew much," Schmitz complains. "But one pharmacist said the consistency of Synthroid was not uniform. An 80 microgram pill could actually be 60 micrograms or 100 micrograms. I also have atrial fibrillation, and it's very important that I take the right micrograms of Synthroid because it could affect my heart condition. It irritates me when a pharmaceutical company doesn't give a darn--especially about the elderly."

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