Desiccated thyroid in the management of hypothyroidism: Part I

Posted by Thomas Repas, DO, FACP, FACE, CDE January 2, 2009 04:32 PM

http://www.endocrinetoday.com/comments.aspx?rid=35717

Before I go any further, I must disclose: I do not use desiccated thyroid (Armour Thyroid, Forest Laboratories Inc.) in the management of hypothyroidism. Like most of my endocrinologist peers, I believe that desiccated thyroid is antiquated therapy and should no longer be used. Guidelines published by the American Association of Clinical Endocrinologists and other major endocrinology professional organizations support this position.

However, I am frequently asked by my patients about desiccated thyroid. Some of them tell me that a family member, friend, alternative care practitioner or other acquaintance has told them they do not “believe” in levothyroxine and advised them to be switched. This, along with several negative comments by patients on this blog about levothyroxine, is why I chose to write about this issue in detail now.

Desiccated thyroid is made from dried and powdered animal thyroid gland, a by-product of domesticated animals raised for the meat industry. For many years in the past, it had been successfully used in the management of hypothyroidism. However, once levothyroxine became available, desiccated thyroid fell out of favor. Recently, there has been resurgence in the use of desiccated thyroid as alternative medicine practitioners have proclaimed the benefits of natural over synthetic thyroid hormone preparations.

So why do I and most other endocrinologists refuse to use desiccated thyroid?

There are a number of reasons. First and foremost, desiccated thyroid preparations have an unacceptable level of variability batch to batch, often resulting in unacceptable variation in thyroid-stimulating hormone. The current USP standards specify that the amounts of levothyroxine and liothyronine in each 65 mg of desiccated thyroid should be 38 mcg and 9 mcg; however, the actual amounts vary considerably. According to the American Society of Health-System Pharmacists “Big Red Book,” the mean concentrations of levothyroxine and liothyronine in each 60 mg of desiccated thyroid ranged from 8.8 mcg to 59 mcg and 7.9 mcg to 18 mcg, respectively.

Part of the problem is that many manufacturers have used iodine content rather than actual thyroid hormone to standardize their preparations. Some manufacturers (ie, Armour Thyroid) perform bioassays to maximize batch-to-batch reproducibility. However, as noted above, the range of levothyroxine and liothyronine can vary considerably, even in products standardized by bioassay instead of iodine content.

I and many endocrinologists are concerned when the brand of levothyroxine is switched without our knowledge to other brands or from brand to generic. Whenever a patient must be switched from one levothyroxine product to another, we always recheck the TSH in several weeks to confirm the dose remains optimal. Even as little as a 10% difference between similarly labeled levothyroxine products can result in large variation in clinical response as measured by TSH. When managing my patients on levothyroxine, sometimes I change the dose by as little as an extra half pill more or less per week

If we consider slight variation between various levothyroxine products to be clinically important, then the much larger variation within desiccated thyroid preparations is unacceptable.

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5 Comments

Filed under Abbott, Armour, Back-order, Bio-identical, Desiccated thyroid, FDA, Government, Hormone, Hypothyroidism, Naturethroid, Synthroid, T3, T4, Thryoid, Uncategorized

5 responses to “Desiccated thyroid in the management of hypothyroidism: Part I

  1. jeaton79

    Can you believe this guy? If Armour works then why change it..hmmmmm I wonder. Was he paid off by Abbott? Someone got to him. He is an arrogant bastard.

  2. The Desiccated Thyroid issue is currently affecting US supplies. Americans have found the next best source. Canada… We ship meds daily to our american Patients.
    http://www.affordabledrugs.com/buy/thyroid

    Pricing sample:
    60mg | 200 tablets – $36.25 US
    125mg | 200 tablets – $46.00 US

  3. Within the great majority of cases, treatment for hypothyroidism is for life. The good thing is, the medications currently available are effective, safe, and will enhance your quality of life.

  4. We are a gaggle of volunteers and starting a brand new scheme in our community. Your web site offered us with helpful info to work on. You’ve done a formidable job and our entire neighborhood will probably be grateful to you.

  5. Olablingola

    Hi, I have been on Armour Thyroid medication for a couple of years already. Well, I still feel tired and sluggish and with two little children it is not getting any easier. At the end of the day I’m simply exhausted and when I wake up in the morning I’m already tired. My doctor says my thyroid levels are just fine, but if Armour doesn’t work for me he can put me on Synthroid. I really want to avoid this drug and save the rest of my falling out hair… I started a new vitamin and natural high in iodine diet, so we will see how it goes. I believe in Armour Thyroid, but I realize that popping a pill once a day might not be enough for me. How do you deal with this problem? Am I the only one with so- so Armour Thyroid effect???

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