An exercise in futility - Levothyroxine dosing

[helvella]

Just read a 2021 paper which discusses levothyroxine dose after total thyroidectomy and says this:

Despite a remarkable commitment by researchers to find a

therapeutic scheme able to predict the exact dose of LT4 to be

given to patients after a total thyroidectomy, the attempt to reach

the precise dosage failed to reach the target in the totality of the

cases. It is reasonable to conclude that because most of the

schemes show a considerable complexity but do not offer

significant advantages in the percentage of patients reaching

the expected results, the search for a fully predictive model seems

to be an exercise of futility. Nonetheless, these schemes are of

great utility to start the replacement therapy approaching the

best dosage, but keeping in mind that changes during follow-up

can be necessary according to the TSH values that are to be

reached in every case.

frontiersin.org/articles/10...

I have now added that paragraph to my discussion of estimation formulas.

helvella.blogspot.com/p/hel...

As I see things, it is an impossible task. I mean, we find so many individuals appear to absorb the same dose of a single make differently depending on whether they get, say, one 100, two 50s or 4 25s.

Let alone the perception of differences between makes.

[Brightness14]

Talk about hit and miss what a shambles. I read a few week ago about a new point system for Levo dosage. The usual dose per kilo was partially done on the patients BMI if someone had a very high BMI is was found that they were taking too much, however, people such as myself with a BMI of 21 where often underdosage. After my thyroidectomy I was given only 100 levo and became very ill after six months so started on NDT. I am now back on Levo after seven years on NDT and have just increased my Levo to 125 so I will see. A bit of an experiment with me in the middle. With no thyroid, no allergies or gut issues I am starting with an even playing field. I will post if I ever fell well again. Thank you for the read by the way.

[Tythrop in reply to Brightness14]

Good luck .

[Tythrop]

Shouldn't they dose according to symptoms? This would mean listening to patients .Also ,following Diogenese, they should add in some Liothoranine/t3 to make up for the t3 a healthy thoride gland adds to the system ???

[helvella Administrator in reply to Tythrop]

You cannot dose according to symptoms when commencing levothyroxine immediately after a total thyroidectomy!

It will take a while to start to see what is happening in order to make adjustments.

And there is an inherent complexity and difference between post-op and any other circumstance - the trauma of the operation, the possibility of thyroid hormone being released from the thyroid, etc.

There is a need for a best guess. But with readiness to adjust in the light of experience - so yes, back to signs and symptoms.

[Tythrop in reply to helvella]

Ah I see ..

[Batty1]

I have asked multiple Endo’s about dosing based on my weight and every single one said no we don’t do that its based on blood test.

Based on weight Im grossly under medicated but according to labs Im fine.

What I find odd is just about everyone I have seen on here without a thyroid is taking 100mcg … How is this?

[helvella Administrator in reply to Batty1]

Well, I do agree that dosing by weight is a poor approach.

But dosing by lab tests alone, especially if they restrict to TSH, is a poor approach with an unsupportable veneer of scientific justification.

[Batty1 in reply to helvella]

I don’t think they care either way tbh.