This is potentially a deeply concerning paper - especially given the way in which adverse events under desiccated thyroid are contrasted against those under levothyroxine. I think an awful lot of levothyroxine adverse events are not reported because so many have become just part of the scenery.
I'd be happy to see desiccated thyroid given a full and clean bill of health by the FDA, the MHRA and anyone else concerned. Though we would have to question the motivations of every player who takes part between now and some uncertain future in which that could occur.
It is particularly interesting that the best-known non-desiccated thyroid combination treatment in the USA is, or rather was, the USA product Thyrolar. Surely, if the issue were simply that animal-based products are inconsistent but synthetic are highly consistent, we'd have seen dominance of the market by Thyrolar? Instead of which it has been unobtainable for something like ten years or longer.
Note that some of the problem is stated to be the difficulty that primary care providers have - which is likely due to their confusion (read inexperience and lack of knowledge) - rather than the product itself? We could very easily argue that a vast number of levothyroxine dose adjustments we see people reporting indicated the same prescriber issues regarding levothyroxine. If they are so readily confused, what are they doing being let loose on patients AT ALL?
Endocr Pract. 2017 Feb 22. doi: 10.4158/EP161584.OR. [Epub ahead of print]
ADVERSE EVENT REPORTING IN PATIENTS TREATED WITH THYROID HORMONE EXTRACT.
Shrestha RT1, Malabanan A2, Haugen BR3, Levy EG4, Hennessey JV2.
• 1From: 1Division of Endocrinology, Diabetes and Metabolism, University of Minnesota, Minneapolis, Minnesota.
• 2Harvard Medical School, Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Gryzmish 6, Boston MA 02215.
• 3Division of Endocrinology, Metabolism & Diabetes, University of Colorado Denver, Aurora, Colorado 80045.
• 4Division of Endocrinology, University of Miami, Miller School of Medicine, Miami FL.
Thyroid hormone extract is used for the treatment of thyroid disorders but limited data exist on adverse events commonly noted by the physicians associated with this use. The purpose of this survey was to report adverse events observed by expert physicians managing patients treated for thyroid disease with thyroid hormones.
Members of the American Thyroid Association, The Endocrine Society and the American Association of Clinical Endocrinologists developed a survey instrument modeled on the FDA's reported adverse events for levothyroxine that would effectively assess the clinical experience of frequent prescribers of thyroid hormone. Survey links were emailed to physicians, and the websites of each society provided links to the data collection form.
A total of 174 reports of adverse events occurring in patients on thyroid hormone extract were received. Ninety-one of these reports were accompanied by alterations in thyrotropin values and were further analyzed. Of these, 62 (68%) subjects had developed new symptoms associated with altered TSH. A majority of TSH changes and symptoms described were consistent with thyrotoxicosis (65%), 2 cases had developed arrhythmias. Reporters noted difficulty in dose adjustment by primary care providers due to confusion in interpreting thyroid function test results while on thyroid extract which often necessitated subspecialty referrals.
These adverse event reports should stimulate consideration by FDA to regulate and monitoring of thyroid hormone extract use and consider standardizing these extracts to meet current standards of manufacture, hormone content, availability and shelf-life like the rigor to which preparations like Levothyroxine are monitored.
The full paper is available for free from this link: