Levothyroxine dose

Recent Blood test results TSH 2 (range 0.3 -5.5) T4 20 (range 10-22) Normal, no further action.

I am only on 50 Levothyroxine and feel I’m not benefiting from this dose, in fact I feel worse than before I was diagnosed hypo 12 months ago.

I have asked if I could trial dose of 75 but GP saying no because I’m in range.

Any thoughts would be greatly appreciated. Thanks

[SeasideSusie Remembering]

Maynan17

You really need to have FT3 tested at the same time as TSH and FT4, FT3 is the most important test because T3 is the active hormone that every cell in our bodies need, low T3 causes symptoms. You have a good level of FT4 but if this is not converting to enough T3 then you wont be optimally medicated.

Did you do your test as we advise:

* Blood draw no later than 9am. This is because TSH is highest early morning and lowers throughout the day. If looking for a diagnosis of hypothyroidism, an increase in dose of Levo or to avoid a reduction then we need the highest possible TSH

* Nothing to eat or drink except water before the blood draw. This is because eating can lower TSH and coffee can affect TSH.

* If taking thyroid hormone replacement, last dose of Levo should be 24 hours before blood draw, if taking NDT or T3 then last dose should be 8-12 hours before blood draw. Adjust timing the day before if necessary. This avoids measuring hormone levels at their peak after ingestion of hormone replacement. Take your thyroid meds after the blood draw. Taking your dose too close to the blood draw will give false high results, leaving any longer gap will give false low results.

* If you take Biotin or a B Complex containing Biotin (B7), leave this off for 7 days before any blood test. This is because if Biotin is used in the testing procedure it can give false results (most labs use biotin).

These are patient to patient tips which we don't discuss with phlebotomists or doctors.

If so then your TSH is too high. The aim of a treated hypo patient on Levo only, generally, is for TSH to be 1 or lower with FT4 and FT3 in the upper part of their reference ranges.

TSH should be no higher than 2 and there is room for it to be much lower according to GP online

gponline.com/endocrinology-...

Under the section

Cardiovascular changes in hypothyroidism

Replacement therapy with levothyroxine should be initiated in all patients to achieve a TSH level of 0.5-2.0pmol/L.

Also, Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine (the professional publication for doctors):

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l. In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l. This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l).*"

*He confirmed, during a talk he gave to The Thyroid Trust, that this applies to Free T3 as well as Total T3 and this is when on Levo only. You can hear this at 1 hour 19 mins to 1 hour 21 minutes in this video of that talk youtu.be/HYhYAVyKzhw(Not working as expected?)

You can obtain a copy of this article from ThyroidUK:

[e-mail]

print it and highlight Question 6 to show your GP.

Plus from the British Thyroid Foundation:

btf-thyroid.org/thyroid-fun...

How can blood tests be used to manage thyroid disorders?

.....

Occasionally patients only feel well if the TSH is below normal or suppressed. This is usually not harmful as long as it is not completely undetectable and/or the FT3 is clearly normal.

There are also certain patients who only feel better if the TSH is just above the reference range. Within the limits described above, it is recommended that patients and their supervising doctors set individual targets that are right for their particular circumstances.

So if your results are accurate (doing the test as mentioned above will give accurate results) there is plenty of scope for an increase in Levo so use the above information to support your request. If GP is reluctant, ask him to compromise by allowing a small increase of, say 12.5mcg, and retesting in 8 weeks, ensuring him that if you have symptoms of overmedication then you will get straight back in touch.

[Hidden in reply to SeasideSusie]

Thank you for your reply. I did blood test as mentioned so results should be accurate. I have had TPO tested last year and was positive for this. Was told T3 not tested at my hospital lab unfortunately. Will think to go privately for this as suggested.

[SlowDragon Administrator]

Just testing TSH and Ft4 is completely inadequate

Bloods should be retested 6-8 weeks after each dose change or brand change in levothyroxine

You should not have been left on starter dose this long

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.

Very important to test vitamin D, folate, ferritin and B12 at least once year minimum

Low vitamin levels are extremely common, especially with autoimmune thyroid disease (Hashimoto’s or Ord’s thyroiditis)

Low vitamin levels common as we get older too

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 and last dose levothyroxine 24 hours before test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Is this how you did your test?

Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins

List of private testing options

thyroiduk.org/getting-a-dia...

Medichecks Thyroid plus antibodies and vitamins

medichecks.com/products/adv...

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test

bluehorizonbloodtests.co.uk...

If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3

£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code

thyroiduk.org/getting-a-dia...

monitormyhealth.org.uk/

NHS easy postal kit vitamin D test £29 via

vitamindtest.org.uk

Likely low vitamin levels if been left woefully under medicated for such long time

[SlowDragon Administrator]

guidelines on dose levothyroxine by weight

Approx how much do you weigh in kilo

Even if we frequently don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose

NICE guidelines on full replacement dose

nice.org.uk/guidance/ng145/...

1.3.6

Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.

Also here

cks.nice.org.uk/topics/hypo...

gp-update.co.uk/Latest-Upda...

Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.

For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.

For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).

If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.

BMJ also clear on dose required

bmj.com/content/368/bmj.m41

Get full thyroid and vitamin testing done privately, testing correctly

Come back with new post once you get results

Obviously you likely need next dose increase in levothyroxine to 75mcg

[Hidden in reply to SlowDragon]

Thank you for responding, grateful for the information shared - I weigh 73 kg

[SlowDragon Administrator in reply to Hidden]

So the likely dose levothyroxine you may eventually need, increasing slowly upwards in 25mcg steps…is 116mcg per day

Come back with new post once you get full thyroid and vitamin testing, likely currently very under medicated