![]() nor were they making unfounded accusations of L-T3 or L-T4 preparations of being dangerous and causing thyrotoxicosis. ![]() these historical scientists were not trying to protect or praise their current “gold standard” thyroid pharmaceutical (desiccated thyroid),.Unlike the writings of some today who vigorously defend L-T4 monotherapy and disparage the T3-based hormone preparations, These studies were pharmaceutically objective and unbiased. Older historical scientific sources are free of today’s “thyroid pharmaceutical prejudice” - a prejudice that leads to severe limitations on T3 hormone dosing today.īefore the tide turned against desiccated thyroid as the gold standard in thyroid therapy (during the 1970s), many scientists had an open-minded curiosity and excitement about both of the two synthetic pharmaceuticals, L-T3 and L-T4. Most importantly, you can’t interview a rat about their thyroid symptoms. But rats metabolize thyroid hormones differently, and rats were not usually taking pills but were often receiving T3 injections. (See “ The foundations of synthetic T3-T4 therapy in the 1990s” and “ Mimicry: The idol of T3-T4 combo therapy 2004-2014“)Īnd of course, throughout thyroid science history, we have a lot of studies of rats or mice dosed with T3. These are all based on a mistaken belief that thyroid hormone combination dosing ought to imitate the narrow statistical average of the secretions of human thyroid glands, estimated by Pilo and team in 1990 in a historic study of 14 men and women. Trials of fixed-dose mini-T3 combination therapies of LT3/LT4 began in the mid-1990s. These scientific sources prior to 1980 were not just doing a short-term 6 week trial of an LT4-LT3 combination, but managing patients for years or decades on each type of therapy.Īfter about 1980, science history mainly gives us studies of short-term L-T3 monotherapy before radioiodine ablation of remnant thyroid tissue after a thyroidectomy for thyroid cancer. Sources before 1980 are truly the most recent scientific findings about long term dosing of all forms of thyroid hormone medication. We pay attention to clinical charts of equivalency from thyroid science history for some other very good reasons. Let’s listen to thyroid science history regarding true clinical equivalence! However, before you go there, it is best to understand the scientific history first, because contemporary thyroid science and therapy has been strongly biased by the TSH-T4 paradigm that arose during the 1980s. P art 2, the next post in this series, discusses the more recent thyroid science on LT4-LT3-NDT pharmaceutical equivalency. In this post, I summarize what five historical thyroid science sources had to say about this equivalence between 19, at a time when researchers and clinicians were very familiar with the use of these medications as monotherapies and combinations.Īt the end, I’ll show the misleading dose-equivalency charts found in pharmaceutical monographs today and discuss why they are so misleading. They raised the ceiling - they gave much higher doses and ranges to L-T3. The bulk of historical clinical research and practice disagreed with limiting L-T3 to such a low dose equivalent. It is naive and potentially harmful to believe that 25 mcg of L-T3 (Liothyronine) is equivalent to 100 mcg of L-T4 (Levothyroxine) at every dose and in every combination and in every patient. They imply that a simple mathematical calculation can estimate dosages of each pharmaceutical in any ratio, either as a combination, or as monotherapies. These statements communicate a misleading message to doctors and patients because they do not provide dose ranges, but rather precise doses. Pharmaceutical equivalency statements in the product monographs for Pfizer Canada’s Cytomel and for ERFA Canada’s “Thyroid” (desiccated thyroid extract, DTE, or natural desiccated thyroid, NDT) both claim that a 25 mcg dose of Liothyronine sodium (L-T3) is “considered equivalent” to 100 mcg / μg (0.1 mg) of Levothyroxine sodium (L-T4). In thyroid therapy, how many micrograms of Cytomel (T3) are equivalent to how many micrograms of Synthroid (T4)? ![]() ![]() Pharmaceutical equivalency of levothyroxine (LT4), liothyronine (LT3) and desiccated thyroidīy thyroidpatientsca on Septem Home › Thyroid therapy › T3-monotherapy › Pharmaceutical equivalency of levothyroxine (LT4), liothyronine (LT3) and desiccated thyroid ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |