RMOC November 2018 Guidance - Prescribing Liothyronine.

[pennyannie]

Hi there, I am currently reading the above and should appreciate a little help :-

I am on page 12 regarding combination treatment with levothyroxine - I'm reading that a dose of T3 10 micrograms requires a dose drop in T4 of 50 micrograms :

I was given to understand that a conversion ratio of T3 to T4 should be around 4.00: and that 6.25 T3 was equal to 25 T4 - a 1 / 4 ratio - thereby a dose of 12.50 T3 would be the correct replacement dose for 50 T4.

Am I going mad, or do I need to up my brain food ?

[jimh111]

T3 is about 4x to 5x as potent as T4 in the blood. Unfortunately endocrinologists are unable to understand that the amount you put in your gob is not the amount that builds up in your blood. L-T3 and L-T4 have different absorption, more importantly the half-life of L-T4 is seven days and L-T3 about one day. Thus although L-T3 has better absorption the longer half life of L-T4 leads to more of it staying around in the blood.

So, what ratio should be used? The best information we have is from this study ncbi.nlm.nih.gov/pmc/articl... which finds that 10 mcg liothyronine is equivalent to 30 mcg levothyroxine. This may not be perfect because it measures the effect on the pituitary (TSH) rather than other tissues but it is the best we have. A 1:3 ratio.

I haven't read the article you reference, I'll take a look at it. It seems that the people that publish it is another useless quango bleeding the NHS dry. I would expect pharmacists to have a basic understanding of pharmacokinetics but apparently the hopeless ones work for SPS.

[pennyannie in reply to jimh111]

Thanks jimh111

It's just that when I flirted with T3 myself I was advised to drop 25 T4 and add 6.25 T3 -

I have since gone on to NDT and find this much more me - it's a bit like having worn stiletto shoes and then swopping into slippers !!!

Am guessing you might know of that feeling though not necessarily through wearing high, spikey winkle picker shoes !!!! No offence meant - just trying for a smile.

Many thanks

[pennyannie in reply to jimh111]

So, me again jim,

just thinking - if a trial of T3 + T4 were to be sanctioned on a 1 / 5 ratio - do you think it would be successful ?

I think not - or am I being simplistic and cynical.

[jimh111 in reply to pennyannie]

About half the trials used 4:1 or 5:1 ratios, the other trials used enough hormone to keep TSH stable. All the ratio trials found liothyronine gave no benefit. Some of the stable TSH trials found liothyronine helped. In fact all of these trials were useless because they did not seek out patients who only recover when given T3. They used the wrong cohorts. So much for peer review.

[pennyannie in reply to jimh111]

Thank you Jim - so it would seems like a stitch up from start to finish.

I could ask at trial stage, that I wish a 1 / 4 ratio - as through self medicating, that ratio works best for me and that a 1 / 5 ratio would leave me unwell.

Think I'll stay away and mind my own business - it's a long haul - don't want to be messed about only to fail -

I know, you can't possible say !!

I'll stay where I am, with my Graves, RAI and TED - I have been refused of a trial of T3 + T4 combo and challenged the decision. I received no answer to my letters and no support from either the endo or my doctor.

I've given up and started self medicating and am better staying away and staying alive with the help of this amazing website and people like your good self.

[shaws Administrator in reply to pennyannie]

At least by 'going it alone' we can pick/choose what suits us by trial and error but doctors or endocrinologists will not.

As they've removed NDT (natural dessicated thyroid hormones) through mis-information and in use, safely, since 1892 in various forms without the need for blood tests and people recovered - the very original resplacement) and recently withdrew T3 also which has left us without a choice and for many on this forum, levothyroxine didn't resolve their symptoms or made any improvement.

Members have recovered by 'going it alone' with help/advice. It may not be instant but we can get there eventually and also by relieving our disabling clinical symptoms.

[pennyannie in reply to shaws]

Yes, it's a very sad state of affairs and somewhat unbelievable to those not living with the condition. I'm hoping I'm now sorted, and never thought that at 71,

I'd have to resort to buying my hormone replacements over the internet,

keeping under the radar, and staying away from the Nhs .

We're all a work in progress and thanks to all of you, for me, much progress has

been made having this site as my goto for all things thyroid.

Many thanks -