New available paper on effects of T3 on volunte... - Thyroid UK

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New available paper on effects of T3 on volunteers (testing cardiovascular effects)

diogenes profile image
diogenesRemembering
7 Replies

This paper just out shows lack of effect of T3 on volunteers cardiac performance etc. Shows that the temporary "spike" in FT3 after dosing has no effect on heart parameters - ie can rule out this potential pproblem giving T3. Below see abstract and conclusions.

Front. Endocrinol., 28 February 2022 | doi.org/10.3389/fendo.2022....

Acute Effects of Liothyronine Administration on Cardiovascular System and Energy Metabolism in Healthy Volunteers

Shanshan Chen, George F. Wohlford, Alessandra Vecchie’, Salvatore Carbone Sahzene Yavuz, Benjamin Van Tassell, Antonio Abbate and Francesco S. Celi

Division of Endocrinology Diabetes and Metabolism, Virginia Commonwealth University, Richmond, VA, United States

Department of Biostatistics, Virginia Commonwealth University, Richmond, VA, United States

Department of Pharmacotherapy and Outcomes Sciences, Virginia Commonwealth University, Richmond, VA, United States

Division of Cardiology, Virginia Commonwealth University, Richmond, VA, United States

Department of Internal Medicine, ASST Sette Laghi, Varese, Italy

Department of Kinesiology and Health Sciences, College of Humanities and Sciences, Virginia Commonwealth University, Richmond, VA, United States

Context: The pharmacokinetics of liothyronine causes concerns for cardiovascular toxicity. While the effects of sustained increase in serum T3 concentrations are well described, little is known on the effects of acute changes in T3 concentrations due to rapid action of thyroid hormone.

Objective: To assess the clinical relevance of transient increase of T3 levels on cardiovascular system and energy metabolism.

Setting: Double-blind, three arms, placebo controlled, cross-over study

Study Participants: Twelve volunteers (3 females, 9 males), age 27.7 ± 5.1 years.

Intervention: Oral administration of liothyronine 0.7 mcg/kg, equimolar dose of levothyroxine (0.86 mcg/kg), or placebo in three identical study visits. Blood samples for total T3, free T4 were collected at times 0’, 60’ 120’ 180’ 240’. Continuous recording of heart rate, blood pressure, and hemodynamic data was performed using the volume clamp method. Resting energy expenditure was measured by indirect calorimetry. An echocardiogram was performed on each study visit at baseline and after the last blood sampling.

Main Outcome Measures: Changes in cardiovascular function and energy expenditure.

Results: Following the administration of liothyronine, serum T3 reached a Cmax of 421 ± 57 ng/dL with an estimated Tmax of 120 ± 26 minutes. No differences between study arms were observed in heart rate, blood pressure, hemodynamics parameters, energy expenditure, and in echocardiogram parameters.

Conclusions: The absence of measurable rapid effects on the cardiovascular system following a high dose of liothyronine supports the rationale to perform long-term studies to assess its safety and effectiveness in patients affected by hypothyroidism.

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diogenes
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7 Replies
diogenes profile image
diogenesRemembering

This finding may well scupper attempts to limit the T3 "spike" by inventing T3 derivatives that mitigate the spike. May be the naked T3 is OK after all.

jgelliss profile image
jgelliss in reply todiogenes

At last some well earned recognition for T3 . The only problem is it wasn't soon enough.Thank you Digenes.

DippyDame profile image
DippyDame

Self medicate

On 100mcg T3.

Have a form of RTH.

Self diagnosed.

Because..

Endo not interested...

He said "Levothyroxine".

It made me ill!

Monitor daily...

Never been aware of spikes or racing heart.

Amazing improvements.

And I'm an ancient....not around 27.7 yrs of age!!

Might stop my GP thinking I'm killing myself!

Thank you diogenes

Charlie-Farley profile image
Charlie-Farley in reply toDippyDame

You’re amazing DippyDame ☺️👍

DippyDame profile image
DippyDame in reply toCharlie-Farley

That's very kind .....but I'm really just a stubborn old woman!! x

shaws profile image
shawsAdministrator

When I took levothyroxine (T4) I had awful palpitations and even the cardiologist was puzzled.

When T3 was added to T4 palpitations decreased but I still didn't feel well but when I took T3 only, palpitations resolved altogether. I feel fine and have no symptoms.

Charlie-Farley profile image
Charlie-Farley

This is a very important piece of work- thank you diogenes- another for my dossier.

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