This should not now be a research priority. It has only become one because of the failure to do the appropriate and necessary research from the 1950s through to now.
Exp Clin Endocrinol Diabetes
2019 Dec 9[Online ahead of print]
Management of Patients Symptomatically Unresponsive to Levothyroxine: Natural Desiccated Thyroid Extract or the Combination of Levothyroxine and Liothyronine? A Research Priority
Adrian Heald 1 2 , Mark Livingston 3 , Dyfrig Hughes 4
Affiliations
• PMID: 31820425
• DOI: 10.1055/a-1062-6167
Abstract
Around 5-10% of hypothyroid patients continue to experience profound and sometimes disabling symptoms, including fatigue, depression and impaired cognition, in spite of being adequately replaced biochemically. The use of the combination of levothyroxine and liothyronine and natural desiccated thyroid extract is controversial for reasons of costs, a lack of evidence of additional benefit over levothyroxine alone, and potential safety concerns. Clinical guidelines caution against the use of both, and advise that only in exceptional cases may a short trial be considered. Natural desiccated thyroid extract is not licensed for use in the UK. However, key deficiencies in the existing evidence-base together with improved understanding of the pharmacology of levothyroxine resistance, indicates that now is the right time for a definitive clinical trial to address this important area of uncertainty.
Helvella I can only speak from my own experience . After my TT I was dosed with T4 only . At first it worked fine . But a few months later palpitations started happening high B/P and many many symptoms where happening with T4 dosing only . The only game changer that proved to work for me well was to lower my T4 dose and adding some T3/NDT. It made a huge difference for me. I'm not a good converter T4 to T3 and the heart has T3 receptor sights that my heart just wasn't getting or getting enough of .
I'm grateful for your great posts and bringing a controversial topic to light that should not be.
We have all struggled for too long - I’ve over 70 thyroid patients on my Twitter timeline in just 6 months of occasional comments about my thyroid - since I started talking about my struggles for getting & paying for my essential NDT - despite having a letter from a consultant ( NHS) saying “ She doesn’t do well on Levothyroxine “
How much evidence do they need for the efficacy of NDT? Is 100 years of successful treatment with it not enough proof? Those that feel well on it or other T3 combination therapy but did not on T4, are living evidence of its superiority in being better for us. More and more evidence of the vital importance of adequate freeT3 for health mounts yet it is known T4 monotherapy leads to abnormally low free T3 levels in those taking it (I presume as an average anyway). Why is it claimed more evidence is needed to prove it works it is safe and it is superior to T4 alone 🙄
Why not allow free choice and let US decide what thyroid hormones therapy works best. But how would we know...just because we deal with the problem every day, when some man in a white coat can torture dozens of mice and look at those who have no thyroid disorder and procrastinate ad nauseum claiming that they haven’t been able to find any “scientific” evidence based proof of any benefit of having the normal hormone levels (the ones that they happily live with) - while we pay the very high price for their patronising paternalistic attitudes and their in-depth studies which appear to me to be completely irrelevant to the problem they wish to (or should I say do not wish) to elucidate . Perhaps rendering them hypothyroid and letting them see how effective Levothyroxine is might concentrate their minds a bit!
Meanwhile, as they fanny about with mice and the healthy trying to see what is patently obvious, I shall keep taking my very dangerous NDT and have a life, for as long as I am able to get hold of it. And I say poor mice...and should reincarnation exist they deserve to come back as lab mice.
Considering that the medical profession hand out statins to all and sundry with no clinical evidence of benefit but plenty of evidence of harm, this is hypocrisy when it is said that there is no evidence of effectiveness of NDT.
And antidepressants...especially to those who continue to suffer hypothyroid symptoms on Levothyroxine how can they justify filling us with that junk whilst refusing us a T3 top up? It’s insane.
Having never taken T4, & feeling dire on T3 only for 8-9 months of the year, I cannot believe the medical industry are so disparaging of NDT, & that it’s not licence here. One of the things mentioned in my first biomedical lecture was that neither paracetamol or aspirin would be given a licence under current clinical trials as we’re unsure why these work. Both drugs are accepted as pharmaceuticals due to such longstanding use. Why not NDT?
I thought it was not licenced because it had a long and successful history of use prior to the system of licensing drugs came in, so it was deemed unnecessary as it’s efficacy and safety was already proven by default 🙄
Thyroid BP was killed off by endocrinologists such as those who wrote this:
Thyroid extract
SIR, -- We write to suggest that thyroid extract (Thyroid, BP) be removed from the British Pharmacopoeia and that its manufacture be abolished.
We continue to see patients who have been diagnosed as having myxoedema and who are being treated with apparently adequate doses of thyroid extract but who are clinically and biochemically hypothyroid. They have subsequently responded to thyroxine.
Although it is never to be certain that drugs prescribed are being taken, there is good evidence the of thyroid extract is variable and its shelf-life dated. As both active constituents. thyroxine and triiodothyronine, have been available for many years we see no reason for the retention of thyroid extract, which we consider to be dangerous.
But why was it unlicensed but could still be prescribed? I thought it was because older medicines were not required to be licenced as it was a newer control for new medicines. I presume it can still be prescribed privately but has even that been banned by our idiotic health care system?
There does tend to be some confusion between USA and UK systems.
For example, levothyroxine was grandfathered until the end of the 20th century. At that point, the issues with the products were so frequent and some manufacturing procedures so questionable that the FDA forced the companies to submit their products as if new medicines.
Whereas, in the UK, levothyroxine had long been under the product licence system.
When UK manufacturers gave up on Thyroid BP, the only options were imports - mostly from the USA. And the usual requirement that the prescriber takes personal responsibility inhibited many from prescribing.
I wonder if there was any truth in their claims about UK NDT being as awful as they imply. It’s a pity we can’t hear what those who used it felt about its efficacy - overruled as usual by the white coats no doubt. I’ve only seen one or two comments on here, all very damning of their experience on Levothyroxine compared to NDT. I presume most have passed away now.
I certainly read of some people who found Armour Thyroid significantly better than Thyroid BP. (I don't know how many companies made Thyroid BP - or when. But there were at some point several manufacturers of desiccated thyroid within the UK.)
The letter I posted was probably just before the era we are now in of chemical assays being accurate and (fairly) cheap. Possibly the manufacturers would have had to pull their socks up in order to continue manufacture?
Of course, some who take desiccated thyroid even now seem to dose by how they feel. If doing that, even fairly significant differences might not have made that much difference to patients?
That’s a good point. You’d just adjust for any variations and I supposed it would be masked. I have to admit I have always dosed by how I feel on NDT. Initially 1.25 grains was fine. Then after a couple of years I had a blip and titrated up to 2.25 which was a surprise I have no idea why I needed such a big increase, but now have settled on 2 grains. I did try a little bit of T3 as well as the NDT but did not find an improvement getting the dose accurate was hopeless with 100 mcg T3 tabs and a pill cutter and teeth! I was not brave enough to up the T3 to something more accurately measurable and drop the NDT right down. I did buy a blood test but have not had success in getting a draw - spigots are hopeless blood just clots immediately. I keep meaning to arrange a venous draw but what a darn faffle that is proving to be....
The basic trouble is that though the authors recognise the shortcomings of current information and trials, they have to take into account (clearly and outspokenly) the reasons why all previous trials on the subject have failed, This is in our papers, showing that a) the fraction of patients not responsive to T4 monotherapy in a random panel is small enough that their responses are swamped by the indifference of the majority who can convert well to T3 and b) mixing all patients up can give a total false appearance and deductions from such trials. Unless the medics get their heads around better statistical handling, the errors and null-information studies will continue. We have addressed this problem several times in our papers together with practical solutions to aid a viable trial.
Thanks for your very important point, which is really at the nub of why these flawed studies do not back up reality, as I know it anyway.
I am intrigued to know what proportion of those on T4 only thyroid hormone replacement therapy actually have normal levels of thyroid hormones as I got the impression that free T3 is “often” much lower than it ought to be compared to that of the healthy population without thyroid disease.
Is it really just a tiny minority as often claimed?
My guess would be 10% definitely poor converters and another 5% mediocre to poor (ie they might or might not just get away with T4 monotherapy at the expense of undetectable TSH). I think my wife is perhaps near or inside the 5% - she can convert adequately but FT4 is on the top edge of FT4's range and TSH around 0.02 or less.
So only around 15%. I must admit all my hypothyroid relatives feel/felt very well on Levothyroxine. It was really gutting to still feel utterly dire after two years on the stuff even with a very low TSH. Two had NHL thyroid cancer so got suppressive doses, but even that did nothing but make me hyperactive agitated and very irascible and generally unwell. I have DIO2 poor conversion combination and some genes for thyroid hormone resistance which might be of relevance. I assume they got a better genetic role of the dice there, but I don’t know (not that NHL thyroid cancer is exactly a genetic prize! I’ve been spared that at least, I assume I can’t get it if mine shrivelled away). I felt rapidly improved on even a very small dose of NDT, and that was within days, and considerably better as I titrated up to a full replacement dose. In fact I soon began to feel completely normal again and my long standing chronic depression disappeared altogether, heart pains went away and my weight and energy levels normalised and my ribs stopped breaking. In some ways I felt better than I had for decades. I felt my health actually deteriorated on Levothyroxine despite being virtually dead before I began treatment - the really bad bit was only the last few weeks when I’d gone totally nuts.
You think they’d try and help the 15% who don’t do well on Levothyroxine rather than demonise us. I hope your research will eventually lead to a better understanding as to why we do not get well again and a more enlightened approach to our treatment as the norm, rather than the exception that has to be fought tooth and nail for.
As well as the poor converters there are also a considerable number with thyroid hormone resistance, who need above range Free T3 to fell well.
I guess that "adequately replaced biochemically" just means in-range blood tests and it is likely that those who failed to respond to NDT or T3 would benefit from higher doses.
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Good advise on 'Treatment Using (NDT) Natural Thyroid Extract' and 'How to Dose with (NDT) Natural Desiccated Porcine Thyroid Extract'
My local Clinical Commissioning Group (CCG) has made a new policy THIS MONTH to stop prescribing T3 and Armour in my area. 
Survey re Clinical and Cost Effectiveness of Thyroid Drugs
