Endocrinology network news reviews study on T3-based therapy prescribing

Good post on “Endocrinology Network” news, summarizing of research and trends regarding T3-based thyroid medication prescriptions for hypothyroidism around the world (not mentioning Canada, though).

Fuerst, M. (2019, February 14). Physician–patient interaction may influence prescribing patterns in hypothyroidism | Endocrinology Network. Retrieved February 25, 2019, from http://www.endocrinologynetwork.com/thyroid-disorders/physicianpatient-interaction-may-influence-prescribing-patterns-hypothyroidism

EndocrinologyNetworkFeb2019articleApparently, In the United States, in 2017, “approximately one-third of physicians taking care of patients with hypothyroidism are willing to prescribe therapies other than levothyroxine (LT4).”

However, don’t have a party yet.

Endocrinologists in charge are not happy about this situation.

One of the studies by Jonklaas that this article reviews (published in January 2019) was actually quite skeptical and really frowned and wagged a finger at those physicians who prescribed the “less-researched” T3-based therapies even when TSH was in normal range on T4.


Jonklaas and colleagues basically say this — (my paraphrase) … “Naughty physicians! They are probably being swayed by Googling and whining thyroid patients and pharmaceutical companies. They should wait until the American Thyroid Association declares that enough research has been done on T3-based meds to prove that they are better than T4 monotherapy and are safe.”

Jaqueline Jonklaas is the head author of ATA hypothyroidism guidelines in 2014, the author of the chapter on the treatment of hypothyroidism in the most important “thyroid textbook,” Werner & Ingbar’s The Thyroid, and several articles that argue against the need for T3-based therapy:

  • Jonklaas, J. (2017). Persistent hypothyroid symptoms in a patient with a normal thyroid stimulating hormone level. Current Opinion in Endocrinology, Diabetes, and Obesity, 24(5), 356–363. https://doi.org/10.1097/MED.0000000000000355
  • Jonklaas, J., & Burman, K. D. (2016). Daily Administration of Short-Acting Liothyronine Is Associated with Significant Triiodothyronine Excursions and Fails to Alter Thyroid-Responsive Parameters. Thyroid, 26(6), 770–778. https://doi.org/10.1089/thy.2015.0629
  • Jonklaas, J., Davidson, B., Bhagat, S., & Soldin, S. J. (2008). Triiodothyronine levels in athyreotic individuals during levothyroxine therapy. JAMA, 299(7), 769–777. https://doi.org/10.1001/jama.299.7.769

Here’s a tidbit from her 2008 article on T3 levels in therapy: “CONCLUSION: In our study, normal T3 levels were achieved with traditional LT4 therapy alone in patients who had undergone near-total or total thyroidectomy, which suggests that T3 administration is not necessary to maintain serum T3 values at their endogenous prethyroidectomy levels.”

From Jonklaas’s 2017 article abstract: “Linking patient dissatisfaction with low triiodothyronine levels has fueled multiple combination therapy trials that have generally not shown improvement in patient quality of life, mood, or cognitive performance. Some trials, however, suggest patient preference for combination therapy. There continues, moreover, to be anecdotal evidence that patients have fewer unresolved symptoms while taking combination therapy.”

Patient preference and anecdote will always be dismissed, and meanwhile they prefer studies that restrict T3-T4 combo therapy to teeny weeny T3-T4 dose ratios that must always (at all costs to other organs and tissues) maintain TSH in the normal range.

Fearful of the fluctuations of T3 in bloodstream, Jonklaas does not want people to take it until there’s a better slow-release version of T3.

From her 2016 article: “clinical research using sustained release triiodothyronine preparations may ultimately enhance the health of our patients.”

This is basically a drumroll for pharmaceutical research that can lead to costly T3 meds for patients on the one hand, and profits for researchers and pharmaceutical companies on the other hand.

When will the ATA and influential naysayers like Jonklaas ever approve unbiased research on T3-based therapies and admit that it is safe and beneficial to many?

The ATA are the historical originators of the TSH monotesting and T4 monotherapy practice.

Few of their articles ever question the efficacy of T4 therapy, and the TSH test and the standard reference ranges are the primary judge of its efficacy in their opinion.


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