Dose adjustment - thyroxine.

[bikebabe]

A brief recap from two weeks ago - I'm 63 yrs on stage 4 cancer treatment but keeping well and active (6 mile walks). I've been on levothyroxine since age of 4 yrs (congenital hypothyroidism - Pendreds). The thyroxine dose was as high as 300 mcg throughout my 20's and 30's and was reduced to 200mcg after my two pregnancies at 35/39 yrs. My free T4 has stayed stubbornly high over past few years and TSH very low even when reducing gradually to 125 mg from 200mcg. My GP practice would like me to continue to reduce my levothyroxine to 100mcg daily but I feel cold, sluggish, my nails keep breaking, and despite the cancer meds that initially gave me a 4x daily habit, I'm now down to once daily and slightly constipated. I also have gilberts syndrome which can affect T4/T3 conversion. I drink 2litres water daily, take 100-125 mcg levothyroxine one hour before breakfast and 2-4 hours before other meds and take my calcium supplements in the evening. The levo generic brand keeps changing. My blood results as follows:

GP march 2022 125mcg Free T4 28.5pmol/L (range 9-24) TSH 0.11 mU/L (range 0.2-5)

GP Dec 2021 150 mcg Free T4 24.3 pmol/L TSH 0.11 mU/L

GP Dec 2015 200mcg Free T3 4.1 pmol/L (no range given)

Blue Horizon march 2022 Free t4 21.4 pmol/L (range 12-22)

Free t3 4.4 pmol/L (range 3.1-6.8)

TSH 0.19 mU/L (0.27-4.2)

Cortisol random 508 nmol/L (166-507)

Thriva April 2022 Active B12 80 pmol/L (37.5-150)

Ferritin 106ug/L (44-150)

Folate 11.8 nmol/L (8.83-30)

I can up my folate though believed my diet was quite varied/optimal. My question is whether I should keep reducing the thyroxine and feel hypothyroid or hold out to stay on this 125mcg dose and see whether introducing tri-iodothyronine might help in reducing T4? As the oncologist said, I'm a bit complex!

Thank you in anticipation, Bikebabe.

[SlowDragon Administrator]

Blue Horizon march 2022

Free t4 21.4 pmol/L (range 12-22)

Free t3 4.4 pmol/L (range 3.1-6.8)

TSH 0.19 mU/L (0.27-4.2)

Presumably test was done as early as possible in morning, ideally before 9am and last dose levothyroxine 24 hours before test?

Which brand of levothyroxine do you prefer

ALWAYS get same brand if you notice difference between brands

Teva brand upsets many people

Like many, many people on just levothyroxine you have poor conversion of Ft4 to Ft3

FT4: 21.4 pmol/l (Range 12 - 22) 94.00%

FT3: 4.4 pmol/l (Range 3.1 - 6.8) only 35.14%

Helpful calculator for working out percentage through range

thyroid.dopiaza.org

What vitamin supplements are you currently taking

Was vitamin D tested

Folate and B12 could be higher

As the oncologist said, I'm a bit complex!

No you’re not complex, you’re like 1000’s of thyroid patients who need addition of T3 prescribed alongside levothyroxine

Email Thyroid U.K. for list of recommended thyroid specialist endocrinologist and doctors who will prescribe T3 or NDT

[e-mail]

[bikebabe in reply to SlowDragon]

Thank you Slow Dragon. Tests were done as advised - before 8.15 am and no thyroxine for 24 hrs. Ive taken vit d supplements for several years along with chondroitin/glucosamine and blood levels are optimal. They monitor it as I have denosumab injections. I’ve received the list of endocrinologist s and see that the one I’m referred to isn’t on that list so will ask to be changed. Hard to know about brands but these have varied a lot over past two years. My usual one before these changes was Mercury Pharma.

[SlowDragon Administrator in reply to bikebabe]

Mercury Pharma make 25mcg, 50mcg and 100mcg tablets and are generally widely available

Request GP specify brand on all future prescriptions

Mercury Pharma is also boxed as Eltroxin

Some private endocrinologist are still doing consultations on zoom, so distance no issue

They would want to see vitamin D result too

[bikebabe in reply to SlowDragon]

Oh interesting about eltroxin - I recall being on that for years. So maybe best to stick to Mercury. My vit d result was 76nmol/l (51-249) in March 2022 so on lowish side but I’m already taking daily supplements of 25mcg - have been doing so for several years. I’ve just picked up covid despite being careful so that’s going to mess things up a bit!

[SlowDragon Administrator in reply to bikebabe]

Sadly modern Eltroxin by Mercury Pharma is nowhere near as good as the original Eltroxin by Goldshield …..which was bought up by Mercury Pharma and immediately discontinued

[bikebabe in reply to SlowDragon]

Familiar story! Take the profits and provide a less robust replacement

[radd]

bikebabe,

I assume your previous high doses were necessitated by taking thyroid meds with food? However, even with reductions you still look over-medicated. If we keep FT4 too high, safety mechanisms start converting it to an inactive form called RT3 which risks causing further unwanted alterations.

I don’t know a lot about Gilberts Syndrome but any changes in liver function will effect thyroid hormones by altering T4-T3 conversion which also governs the livers activity and metabolism. Has any doctor ever discussed introducing some T3 meds?

This would allow you to reduce T4 levels and raise T3 as your levels are low. T3 is the active hormone that brings us well-being, and we often only require a little T3 meds as its presence kicks enzymes into encouraging further T3 by conversion from the T4 we already have.

All thyroid hormones require certain cofactors to be optimised in order to perform best. Ferritin & Vit B12 looks good, folate could be higher. What about Vit D?

Sorry to hear about your cancer.

[bikebabe in reply to radd]

Thank you Radd, I’ve had discussions about T3 with GP over several years and they have always provided excellent care. They have agreed to refer me to an endocrinologist but I need to ask that it’s one on the list who supports T3 prescribing. I’ve never had to think about my thyroid until my menopause as have been on it so long but taking care with timing of dose has changed things. Thanks re cancer empathy. I’m doing rather well and am glad I can do everything I’ve done before though slower!

[bikebabe in reply to radd]

Radd- Might I ask what RT3 does that’s unhelpful?

[radd in reply to bikebabe]

bikebabe,

Good cellular activity or deactivation of thyroid hormone is controlled by deiodinase enzymes (D1, D2, D3) that change in response to differing physiologic conditions, such as levels of thyroid hormone, good health or severe illness, optimal nutrients/iron or deficiencies, etc, but their behaviours also influence each other.

It is not the RT3 per se that is damaging but the mechanisms driving it (D3) that also correspondingly convert our precious T3 to become inactive metabolites. D3 will also block the little T3 we have left from entering the cell’s nucleus (not RT3).

And then there is knock-on effects such as low T3 that will down-regulate D1 resulting in impaired RT3 blood clearance, and losing efficiency in T4 - T3 conversion, so reducing T3 levels further.

There is more but you must get the picture now 😊

[bikebabe in reply to radd]

Thank you Radd. That’s very helpful.

[bikebabe in reply to radd]

Radd - one more query if that’s ok. Despite taking daily 25mcg vit d, my vit d3/d2 blood result is suboptimal. Clearly I can’t increase the dose as am maxed out. I’m on denosumab to strengthen my bones and calcium supplements. Might this be a factor at play or should I swap my vit d brand?

[radd in reply to bikebabe]

bikebabe,

I have read Denosumab can reduce calcium levels but I don't know about Vit D. Anyway, if your levels are suboptimal, then you will have room to increase your dose quite substantiously.

You may even need a loading dose that you can then maintain. We should take Vit D with Vit K2 which helps direct calcium to where it should go. Do you know your exact levels?

[bikebabe]

No - but I will find out!