Brought to you by Mary Shomon Your Thyroid Guide
Letter from Mary Shomon to Peter Lurie, MD, and Betty Blount of Public Citizen -- September 5, 2003
For background, read:
Betty Blount, RN
Volunteer
Peter Lurie, MD, MPH
Deputy Director
Health Research Group
Public Citizen
1600 20th St. NW
Washington, DC. 20009
Dear Ms. Blount and Dr. Lurie:
I am relieved that Public Citizen has finally made the decision to correct the errors that were being disseminated regarding Armour/desiccated thyroid being a non-prescription herbal supplement.
I have reviewed the letter you are sending out to consumers, and while you do correct the main area of error, it appears that Public Citizen is still disseminating misinformation about desiccated thyroid. I have outlined my various concerns; the direct quotations from your letter are bolded.
In your letter to consumers, you say the following:
Nonetheless, we stand by our assertion that desiccated thyroid should not be used in the management of hypothyroidism. Our reasoning depends on an understanding of thyroid hormone function in the body. The most active thyroid hormone, T3, is formed by removing one of four iodine atoms from a precursor molecule called T4 (also called levothyroxine, the ingredient in most thyroid replacement formulations).
If this is representative of Public Citizen’s understanding of thyroid hormone function in the body, then this raises significant additional concerns for patients as to the accuracy of information your organization is disseminating. Thyroxine – not levothyroxine – is T4, and thyroxine is found naturally in the body. Thyroxine is also found in desiccated thyroid drugs such as Armour. Levothyroxine -- also known as “l-thyroxine” or sometimes, “L-T4” -- is a synthetic, manufactured drug designed to replicate the biological actions of T4. T4/thyroxine is NOT the ingredient in most thyroid replacement formulations -- levothyroxine is.
You also say:
“Because T4 is converted to T3 at a predictable rate…”
This is not established as scientific fact. In fact, there are various studies that show that this is NOT the case.
A number of studies have shown that conversion of T4 to T3, a process also known as deiodination, may be influenced by various conditions. (Sapin R, et. al. "Thyroxine (T4) and tri-iodothyronine (T3) measurements]," Ann Biol Clin (Paris). 2003 Jul-Aug; 61(4):411-20).
For example, various substances including beta blockers (Wiersinga WM. "Propranolol and thyroid hormone metabolism," Thyroid. 1991 Summer;1(3):273-7) and adrenaline (Turakulov, "Changes in the ratio of secreted thyroid hormones under the action of adrenaline, propranolol and thyrotropic hormone," Probl Endokrinol (Mosk). IaKh, 989 Nov-Dec;35(6):76-8) can interfere with effective deiodination, especially in peripheral tissues.
According to Arthur Prange, MD, a renowned researcher who has studied thyroid hormones extensively, "there are two general mechanisms that may shift the balance between triiodothyronine and thyroxine: the thyroid gland may change its pattern of secretion; other tissues may change their rates of deiodination." (Prange, Jr., Arthur J. MD "Thyroid Axis Sustaining Hypothesis of Posttraumatic Stress Disorder," Psychosomatic Medicine 61:139-140 (1999))
You also say:
“…the FDA regulates T4 (also a prescription drug)…”
Again, please note that T4 is not a prescription drug. Levothyroxine (L-thyroxine/L-T4) is a prescription drug. T4 is natural thyroxine, and is only found as a component in desiccated thyroid.
Your letter states:
In contrast, desiccated thyroid is formulated from ground pig thyroid gland, and thus has a mixture of active and inactive thyroid molecules: T4, T3, and even molecules with only one or two iodine atoms, which have essentially no activity.
Actually, the molecules with only one or two iodine atoms -- diiodothyronine (T2) and monoiodothyronine (T1) -- do appear to have functions and activities in the body, which are being studied further. For example, T2 levels elevate during hyperthyroidism, and in newborns, and values have been found to be depressed in nonthyroidal illnesses Monoiodothyronine levels are very high in hyperthyroidism and low in hypothyroidism. Some practitioners believe that research will show that the reason some patients respond best to desiccated thyroid is that they benefit from the addition of these lesser-known, lesser-understood thyroid hormones. (De Groot, Leslie J. M.D., Georg Hennemann, M.D., Thyroid Manager, December 2002. http://www.thyroidmanager.org/Chapter6/Ch-6-3.htm)
Your letter goes on to indicate:
Because desiccated thyroid is an unpredictable mixture of these compounds,
This is incorrect.
According to Armour’s manufacturers, “The amount of thyroid hormone present in the thyroid gland may vary from animal to animal. To ensure that Armour Thyroid tablets are consistently potent from tablet to tablet and lot to lot, analytical tests are performed on the thyroid powder (raw material) and on the actual tablets (finished product) to measure actual T4 and T3 activity. Different lots of thyroid powder are mixed together and analyzed to achieve the desired ratio of T4 to T3 in each lot of tablets. This method ensures that each strength of Armour Thyroid will be consistent with the United States Pharmacopoeia (USP) official standards and specifications for desiccated thyroid lot-to-lot consistency. The ratio of T4 to T3 equals 4.22:1 (4.22 parts of T4 to one part of T3).”
If the United States Pharmacopoeia (USP) maintains official standards and specifications for desiccated thyroid, and the prescription drugs available on the market meet those official standards, then how can prescription desiccated thyroid be, as you state, “an unpredictable mixture?” Are you indicating that the USP is inaccurate? Are there studies that show that Armour Thyroid is not satisfying USP standards? If so, I’d ask for references to such studies or information, as I have been unable to uncover this in research.
Your letter also goes on to say:
“…the FDA only requires that iodine content (as opposed to hormone content) be measured. Thus, there is no way of knowing if the iodine present is in an active or inactive form, and therefore what the compound’s biological activity will be. ”
This completely overlooks the fact that the leaders in the endocrinology community consider the standard for evaluating thyroid hormone replacement to be the TSH test. The proof is in the biological action. Symptoms are either relieved, or they’re not. TSH levels, as well as Free T4 and Free T3 levels, either normalize, or they don’t. Again, is Public Citizen suggesting that the doctors writing 2 million prescriptions a year for Armour are not evaluating their patients’ response to the drug being prescribed, or that the patients themselves are oblivious to whether or not the drug is having a effect on their thyroid symptoms?
Levothyroxine drug manufacturers are, in fact, presently lobbying the FDA to change the method of assessing the effectiveness and bioequivalence of levothyroxine products, and one of the objectives is to utilize the TSH test as a standard. Research and discussions on this topic will help to reveal further what criteria the FDA will be adopting for evaluation of levothyroxine.
But in the meantime, there are no current, peer reviewed, double-blind studies that I am aware of that compare levothyroxine to desiccated thyroid in their ability to maintain thyroxine (T4) levels. If you are aware of such studies that would justify Public Citizen’s position, please share them with your me and your other subscribers, as I have been unable to locate any.
You indicate that:
We cannot recommend products whose biological activity we cannot reasonably predict.
In that case, then, your recommendations should also include levothyroxine drugs, because their own manufacturers are arguing that their biological activity cannot reasonably be predicted. As is being argued in the Citizen’s Petition submitted to the FDA by Abbott Laboratories on August 25, 2003:
"If two manufacturers' levothyroxine products differ by only a small margin, substitution of one for the other is likely to lead to therapeutic failures."
They also say:
"With the agency's methodology, for example, a product that delivers 112 micrograms ("mcg") of levothyroxine has a high likelihood of being declared equivalent to a product that delivers 100 mcg of levothyroxine. This difference -- for products intended to be interchangeable -- can cause serious harm to patients.” (Citizen Petition, August 25, 2003, from John Leonard, MD of Abbott Laboratories, to the Food and Drug Administration.)
Your letter states:
“The result is that one cannot know with sufficient certainty how much active thyroid hormone will be released into the blood and patients can become either hypothyroid from insufficient hormone or toxic from too high a dose of the hormone.”
However, this same thing can be said of levothyroxine. Patients respond differently to levothyroxine drugs and desiccated thyroid drugs, and proper management of a patient on ANY thyroid hormone replacement regimen requires periodic – sometimes frequent -- monitoring using laboratory testing. Clearly, many physicians do not have sufficient certainly of how much active hormone will be released into the blood, as the February 2000 issue of the Archives of Internal Medicine found in their report on a cross-sectional study of participants. They found that among patients taking thyroid medication, only 60% were within the normal range of TSH. The fact that forty percent of patients, a number that translates to millions of Americans, are taking thyroid hormone – the overwhelming majority taking levothyroxine -- and are still not in TSH range indicates that either vast numbers of doctors and patients do not know how to properly prescribe and take levothyroxine, or it may not be as predictable and certain as Public Citizen believes it to be.
Your letter continues:
There could be big variations in biological activity not only between T4 preparations and desiccated thyroid, but also between bottles of desiccated thyroid.
Again, I would ask for the specific sources of this particular claim, as I have not been able to find research that demonstrates that this is the case with the currently FDA-approved thyroid hormone replacement drugs. Certainly, there may be inconsistency and variations in biological activity of over-the-counter, non-prescription thyroid glandular supplements. Public Citizen appears to have clarified the prior internal organizational confusion over the difference between Armour and other approved prescription desiccated products, and the non-prescription thyroid glandulars.
However, it still appears that your organization may be incorrectly applying anecdotal assumptions about non-prescription supplements to prescription drugs, simply because they both are meant to act on the thyroid. I would encourage Public Citizen to clarify this point of confusion.
Personally, while in the past I’ve held your organization in high esteem, it is becoming increasing difficult for consumers to trust Public Citizen on issues related to drug information, health and public safety, given the poorly researched information we’ve seen related to thyroid drugs.
I continue to grow even more concerned when I see your organization’s defensiveness regarding your poorly researched position on thyroid drugs, a position that appears to be based not on data or research, but on a very narrow, shaky opinion. And if opinion is going to be the basis for your recommendations, it’s unfortunate that you haven’t even considered the opinion of the patients and practitioners who are actually using and prescribing the drug you are condemning.
I greatly appreciate that Public Citizen has at least corrected the potentially dangerous error that you were disseminating regarding Armour being a non-prescription herbal supplement. However, I find it unconscionable, irresponsible and indefensible to have published your “Worst Pills, Best Pills” condemnation without sufficient research, and now, in the face of valid concerns regarding that position, to refuse to delve into the issue, research the facts, and revisit that condemnation.
Public Citizen’s stonewalling of patient and practitioner input on the thyroid drug issue, and the refusal to consider the financial and health ramifications of your condemnation of Armour Thyroid on the patient community is particularly inexplicable, especially for an organization that claims to represent the public’s interest against major corporations.
For the third time, I publicly call on Public Citizen and Worst Pills to do several things to remedy this wrong and restore your organization’s credibility with the 20 million thyroid patients in America, not to mention the hundreds of millions of consumers who may be the recipients of your health care opinions:
- Issue a complete clarification and correction in your next Worst Pills newsletter,
indicating that Armour Thyroid is NOT an unregulated, over-the-counter herbal or prescription remedy, and correcting the other misinformation being provided in your article and email responses.
- Make the clarification immediately available to readers -- including those without paid subscription -- at your Worst Pills website.
- Issue a press release notifying the public of the error
Public Citizen’s credibility continues to be at stake, and I only hope that your organization does what it will take to restore public confidence.
Sincerely,
Mary J. Shomon
