Thyroxine dose

[Countrylou]

Following on from my last post.

After seeing the endocrinology nurse and subsequent instruction to reduce my dose from 100mcg to 75mcg due to very low TSH (which has been below 1 for years) the symptoms returned after 6 weeks... with avengeance!

Headaches at 5am every morning, extreme fatigue and generally feeling ill.

I had the TFTs repeated on Monday (week 8) and promptly increased back.

Got the results from GP this morning all all wonderful!

T3 5.4. T4 11 and TSH 0.98 (not been that high for a long time.

My thyroid scan was normal apart from

“Sub centimetre U2 nodules on both lobes”

I go back to see the endocrinologist (doctor this time) on the 14th

I am at a loss! I felt so much better on the 100mcg dose but the blood results didn’t agree!

Apparently I risk osteoporosis and/or atrial fibrillation if I go back up to 100mcg.

Any advice please?

I did have the test done first thing in the morning before food/drink and thyroxine but last time I didn’t because it was an unexpected test later in the day

[RedApple]

Simple... they don't understand how thyroid hormone levels affect an individual, regardless of the numbers! That said, if your TSH is sepressed and FT4 above the range, it's just possible your sleep and feet problems might improve if you had a tiny decrease in levo dose. Too much thyroid hormone can cause symptoms too. Getting your FT3 tested might shed some further light on that though.

[RedApple in reply to RedApple]

Ah, I see you've now added further info. Please edit again to include the ranges for your test results.

[Countrylou]

5/11/2019 TSH 0.4. T4 14.4 T3 5.1

30/12/2019 TSH 0.98. T4 11. T3 5.4

[SlowDragon Administrator in reply to Countrylou]

On 100mcg

FT4 70% through range

FT3 53% through range

On 75% mcg

FT4 only 40% through range

FT3 63% through range

So your increased TSH is helping improve conversion of FT4 to FT3.....but you are going to run out of FT4

If you remain on 75mcg Levothyroxine next test FT4 likely to be below range

Helpful calculator for working out percentage through range

chorobytarczycy.eu/kalkulator

Likely you have low vitamin levels too

You probably need to be on at least 100mcg Levothyroxine

plus possibly need addition of small doses of T3 alongside Levothyroxine

Getting all four vitamins tested and optimal may help improve conversion of FT4 to FT3

[Countrylou]

Ranges

T4 7-17 pmol/L

T3 3.5-6.5 pmol/L

TSH 0.35-5.5 mU/L

[Countrylou]

I take 6000 IU of Vit D a day also

[SlowDragon Administrator]

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies

Ask GP to test vitamin levels

Do you have Hashimoto's?

You may need to get full Thyroid testing privately as NHS refuses to test TG antibodies if TPO antibodies are negative

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies

thyroiduk.org.uk/tuk/testin...

For thyroid including antibodies and vitamins

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

The aim of Levothyroxine is to increase the dose slowly in 25mcg steps upwards until TSH is under 2 (many need TSH significantly under one) and most important is that FT4 in top third of range and FT3 at least half way in range

NHS guidelines on Levothyroxine including that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine.

nhs.uk/medicines/levothyrox...

[Countrylou]

Yes a spray

[jimh111]

Your endocrinologist is basing their views on hearsay rather than evidence. There have been a few (good) studies, this is one of the better ones: -

academic.oup.com/jcem/artic...

This study shows that risks increase when TSH goes below 0.04. That is 0.04 not 0.4.

[Jazzw in reply to jimh111]

Maybe... but as with all research I’m not sure they’ve considered all the variables.

For example, could the tendency to bone fractures actually be linked to years of being undiagnosed with hypothyroidism or being kept on too low a dose for a period of time? Or could the results be muddied by people having undiagnosed pituitary failure?

We know that hypothyroid patients experience difficulties with absorbing key nutrients, for example, Vit D, magnesium, B12 etc. So couldn’t it actually be that being hypothyroid for a long period (which you could easily be even with a low or suppressed TSH) is the thing that really predicts tendency to bone fractures rather than the TSH?

It’s an interesting topic nonetheless and I’m certainly not saying the researcher’s conclusions are wrong—I’ve also read that non-suppressed TSH levels may be crucial to the conversion of T4 to T3, so there are definitely things about the role of TSH we’re yet to fully understand.

[jimh111 in reply to Jazzw]

There are many factors that affect osteoporosis and atrial fibrillation. The study I cited finds that a TSH below 0.04 is associated with increased risks. It also finds that a mildy elevated TSH has risks, something endocrinologists always ignore.

TSH is just one parameter and can be useful as a marker for overall thyroid status, but not in every case. TSH plays a role in bone formation, bone has TSH receptors. Little is known about this. I suspect it is a minor factor as people on levothyroxine with a suppressed TSH don't seem to be at increased risk of bone fractures. (Bear in mind that patients with hyperthyroidism often have parathyroid problems that confounded the older studies).

TSH certainly has a role in T4 to T3 conversion, a point I hammer home in my website under the 'Subnormal TSH Secretion' topic. I try to use the term 'low TSH' rather than 'suppressed TSH' if there is doubt as to whether TSH is low due to high hormone levels. Many patients have a low TSH because of subnormal secretion rather than supression by too much hormone.

I referenced the study to point out that TSH has to be very low before it is associated with increased risks.

[Jazzw in reply to jimh111]

Absolutely—and many thanks for this additional info.

[Countrylou in reply to jimh111]

Thank you for that information