Levo mcg - Kilos of Bodyweight?: I am sure I saw... - Thyroid UK

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Levo mcg - Kilos of Bodyweight?

Ellie-Louise profile image
11 Replies

I am sure I saw something the other day about 1.6 mcg to kilos of weight mentioned. But I can’t seem to find it now to read again.

Is that a guide to how much medication a person should be on or something else? The way I am feeling now after having mine reduced makes me think I should be on more again.

I am seeing doc in the morning and wanted to be sure in my mind before opening my mouth.

Thanks x

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Ellie-Louise profile image
Ellie-Louise
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SeasideSusie profile image
SeasideSusieRemembering

Ellie-Louise

The new NICE guidelines mention that new patients can be started on Levo with the dose based on 1.6mcg per kg of weight

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

Initiation and titration

The dose of levothyroxine (LT4) should be individualized on the basis of clinical response and thyroid function test (TFT) results. Treatment must be monitored regularly to determine an adequate dose and to avoid both under- and over-treatment.

The NICE clinical guideline recommends:

Consider starting LT4 at a dosage of 1.6 micrograms per kilogram of bodyweight per day (rounded to the nearest 25 micrograms) for adults under 65 years of age with primary hypothyroidism and no history of cardiovascular disease.

Consider starting LT4 at a dosage of 25–50 micrograms per day with titration for adults aged 65 years and over, and adults with a history of cardiovascular disease.

With the BNF offering this alternative:

The British National Formulary (BNF) recommends:

For adults aged 18–49 years — initially 50–100 micrograms once daily; adjusted in steps of 25–50 micrograms every 3–4 weeks, adjusted according to response; maintenance 100–200 micrograms once daily.

For adults aged 50 years and over, with cardiovascular disease, or severe hypothyroidism — initially 25 micrograms once daily; adjusted in steps of 25 micrograms every 4 weeks, adjusted according to response; maintenance 50–200 micrograms once daily.

It must be remembered that the dose by weight is an option for a starter dose as it also says:

Treatment must be monitored regularly to determine an adequate dose and to avoid both under- and over-treatment.

so they are saying monitor the patient and adjust the dose as necessary as in this guideline:

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

1.4 Follow-up and monitoring of primary hypothyroidism

Tests for follow-up and monitoring of primary hypothyroidism

1.4.1 Aim to maintain TSH levels within the reference range when treating primary hypothyroidism with levothyroxine. If symptoms persist, consider adjusting the dose of levothyroxine further to achieve optimal wellbeing, but avoid using doses that cause TSH suppression or thyrotoxicosis.

So nothing is set in stone, it's all about finding the correct dose for the individual patient to alleviate their symptoms.

Ellie-Louise profile image
Ellie-Louise in reply toSeasideSusie

Thank you, looks like it doesn’t apply to me then.

SeasideSusie profile image
SeasideSusieRemembering in reply toEllie-Louise

Ellie-Louise

Not really. It may be that your optimal dose does work out at or near that amount, but that would be coincidental.

Looking at your recent post here:

healthunlocked.com/thyroidu...

the fact that you have become symptomatic since your reduction in dose of Levo and that your FT4 is only 59% through range, it seems that your GP is only looking at TSH which replies in that thread explained was wrong and it's the FT4 and, more importantly, FT3 that tell us our thyroid status.

You have past history of feeling well on 100mcg Levo and this should tell your GP that as long as FT3 was in range this was the correct dose for you.

If your GP is fixated on your low TSH then use the following information to show him that it is fine as long as FT3 is within range

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 in November 2018 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

You can obtain a copy of the article which contains this quote from ThyroidUK

Email : tukadmin@thyroiduk.org

and ask for the Dr Toft article from Pulse magazine. Print it and highlight Question 6 to show your GP.

Many doctors worry about suppressed TSH but it's not the demon it's made out to be as long as FT3 is within range. Suppressed TSH connected to hypERthyroidism is different from suppressed TSH in treated hyp0thyroidism. Just to illustrate, I have been diagnosed/treated with Levo since 1975 and I've been keeping a record of my results since 1995, my TSH was suppressed back then and it's suppressed now - and depending on which lab tests (NHS or private) it comes back as

0.005

<0/005

<0.1

<0.02

and depending on who looks at my results - GP or Advanced Nurse Practioner - I get a different reaction. The GP totally freaks out and insists I reduce my dose, the ANP knows better than the GP and is fine as long as FT4/FT3 is within range. The ANP also told me not to take my Levo before the test due to it spiking the hormone levels, he told me to take my Levo after the test. Unfortunately he was the only one in the surgery who understood all this and has now left :(

I am also very similar in age to you, so any talk about needing higher TSH as we get older is bunkum as far as I'm concerned. I've lived with suppressed TSH for at least about 30 years and it hasn't killed me yet, nor has it caused osteoporosis nor atrial fibrilation.

Ellie-Louise profile image
Ellie-Louise in reply toSeasideSusie

It was another doctor who reduced my dose a good few weeks ago now, it was after I had that high blood pressure episode and then the thyroid blood test. I tried to tell him that TSH had not a lot to do with it but he insisted on lowering it. If I was braver I would have ignored him. Doc I see tomorrow is more open to patients knowing what’s what, I used to always see him before. I wish we could stick to one doc but when there are a few in the practice that isn’t always possible.

helvella profile image
helvellaAdministrator

Don't take anything as "should". We are all different.

The simple fact that we vary in how much we absorb makes a considerable difference. Could be in the range 60 to 80% of the claimed potency. Which would make a bigger difference than choosing between 1.5 or 1.7 micrograms per kilogram.

The NICE guidance goes on about weight based dosing then admits it might need further adjustment.

nice.org.uk/guidance/ng145

helvella - Estimation of Levothyroxine Requirement in Adults

A discussion about the use of formulas to estimate levothyroxine dosing.

From Dropbox:

dropbox.com/s/gzeknihf815rb...

From Google Drive:

drive.google.com/file/d/1Zs...

A spreadsheet with several active formulas which work out possible levothyroxine requirements including NICE NG145 guidelines. These formulas are referred to in the document above.

This is an Excel spreadsheet but is likely to work in other spreadsheet software.

From Dropbox:

dropbox.com/s/aciho6m7x6f1e...

From Google Drive:

docs.google.com/spreadsheet...

SlowDragon profile image
SlowDragonAdministrator

Which brand of levothyroxine are you currently taking

Teva is only brand that makes 75mcg tablets

Teva brand upsets many people

Recommend getting TSH, Ft4 and Ft3 tested via Monitor My Health

£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/

Always do private testing early Monday or Tuesday morning, ideally before 9am

Don’t test in heatwave

How much do you weigh in kilo

You might need SMALL dose increase….eg 100mcg twice week and 75mcg 5 days

Ellie-Louise profile image
Ellie-Louise in reply toSlowDragon

Accord from Northstar. I split the 50’s. I weigh around 69-70k thereabouts normally, but went a few grams over the 70 last week. I shall weigh myself after a shower. Things are going a bit slow today, I am only just eating (forgotten about) breakfast. Lol

SlowDragon profile image
SlowDragonAdministrator in reply toEllie-Louise

So yes guidelines on dose by weight would suggest you are likely under medicated

You could

A) get Monitor My Health test first

Or

B) try asking GP for small dose increase to 100mcg 3 days a week and 75mcg 4 days a week

Test TSH, Ft4 and Ft3 after 6-8 weeks on increased dose

If you find higher dose too much to tolerate…..Perhaps consider splitting the dose levothyroxine…..taking half at bedtime and half waking

Ellie-Louise profile image
Ellie-Louise in reply toSlowDragon

Thanks, I will suggest that slight increase to him.

The thing that worries me about diy blood is getting enough to come out. I know lots of people do, but my brain makes me think the opposite.

Brightness14 profile image
Brightness14

If I was taking 100mcg of Levo I would be crawling around the floor. I weigh 63 kilos. so for me it wouldn't work. Perhaps as a starter dose, maybe.

Ellie-Louise profile image
Ellie-Louise

I’m just back from the doctors, he was very understanding and agreed to me changing my Levo dose for half the week ( as is suggested in the posts above), and then have a blood test in 6-8 weeks.

I mentioned that because T3 hadn’t been tested last time I was thinking of getting a private blood test done.

He said he could ask specifically for T3 to be tested, and told me he will get the TSH, T3 and T4 done for me. It’s on the computer for when I am ready to make an appointment.

😀

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