Two years ago I posted an article from Medscape regarding the action of NDT (DTE) and its pharmacokinetics. People since asked me to forward it on here, but until now I'd lost the site. I've now retreived it forTUK archives:
If you put into Google the following, the site comes up
medscape/desiccated thyroid extract
Thanks Diogenes - several Medscape search results come up. Was there one in particular?
link to original post if it helps:
healthunlocked.com/thyroidu...
waveylines
Thanks Tattybogle. I was looking for that actual research article Diogenes is referring to as I don't think my doctor will take note of the post otherwise. Do we have that? I now know though why I much prefer ndt to Liothyronine. 😊
humanbean has put it below
Was it this article?
reference.medscape.com/drug...
Hi Humanbean....I don't think this is the right link. The link takes you to instruction for taking ndt with info on medication that are contrary indicated etc....Am looking for the research article in relation to the research that Diogenes talks about above. If u have it that would be Brill. And maybe one that Thyroid UK might want on their website.....unless it's already there....haven't looked! Lol 🙄
I think you need to click on the tabs at the left!
reference.medscape.com/drug...
Thanks, Helvella! I didn't realise that's where it came from. Curious though that the T3 content takes 2-3 days to peak but the half life 2 1/2 days. How does that work?
I think that the half-life is the official half-life for T3. Though we very often see a shorter time quoted.
But the time to peak being around the same, or longer, is the oddity which requires research and explanation.
I know that was what I meant....how can it peak AFTER the half life? Doesn't make sense. Maybe it's typo?
Also doesn't it mean that even if you don't take ndt for 24hrs before a blood test the T3 levels still won't have peaked..... So like the liothyroine you are leaving it 6-8 hrs to test it mid range.....but it looks like to do that with ndt you'd have to stop taking it for more than 3days? Or 1 1/2days to catch the T3 half way on it way up? No wonder the blood tests weren't designed for NDT!!
that would apply if it was the first dose you ever took .. but in reality you're taking it every day so even though its' still 'on its way up' ...every time you add another dose at 24 hrs , the previous dose ( and the one before that etc ) is still there.. so by testing at eg 12 hrs you're measuring 'all of them '
sort of ?
ps 8-12 hrs is more the like mid range for Lio/T3 .. 6 hrs is a bit too close and may include the tail end of the peak.
Yes but this is not the case for ndt tattyboogle. That's why I've always been told to leave 24hrs by my doctors. The problem is blood tests were not designed for testing ndt but for levothyroxine & liothyronine. Different products with different uptake. Can't apply the same procedure .
We already have this issue!
Remember some of the T3 contributing to the peak will be from conversion of T4.
People like me, on T4 monotherapy, should expect a T3 peak around 48 hours after taking my levothyroxine tablet.
But with thyroglobulin binding the thyroid hormones in NDT, there could be further slowing down. (If that is what is happening.)
We really need a continuous (or at least several times a day) test! They are getting there for diabetes. Despite "them" never thinking it would be relevant or informative, just seeing what happens in a few people - with and without known thyroid issues - over a few weeks/months would be fascinating.
Sorry Helvells I don't understand what you are saying. The uptake is different in NDT. I don't think you need to do the 8hr thing you are all talking about for liothyronine (not that you can really do that with ndt) because ndt T3 will have a more even less high peak /low trough response.....therefore leaving for 24hrs won't really affect theT3 level like it does in liothyroine. It also means you will get an accurate Ft4 reading as per the manufacturers test recommendations which you wont if you follow the guidelines recommended on here. And then there is the question of how accurate are the blood tests when measuring ndt T4 & Ndt T3 levels when the tests were designed for levothyroxine & Liothyroinine....not ndt.
They are very much there re diabetes Helvella... well they think they are Though a friend of mine hates the synthectic insulin....another sorry story but loves the pump that constantly measure & keeps her levels correct no matter if she's running or sleeping. A sleep later I've re read your message....😄 However you are still missing the point both T4 & T3 have a slower uptake with ndt. The peaks are different. The half life is different. I hear what you are saying re levothyroxine conversion....but notice you don't split your levo thyroxine dose before testing either to take account of the converted T3. So that doesn't really follow. My point is ndt behaves very differently to liothyronine so I don't understand the recommendation on here for splitting the ndt dose to get a Ft3 reading. This recommendation is based on how liothyroinine is tested, which has a much faster uptake & much faster peak. Its a different product with a different profile to liothyronine. Tracking the levels constantly would be interesting. Don't think big pharma would want this though because it would likely show from what Diogenes said from the pharmaceutical information published more gentle peaks troughs for ndt of T3 then liothyroinine.
Also it would be complex monitoring it like this because the T3 in a normal functioning body has its own natural up/down cycle of thythm....plus ud have to allow for different levels of activity & demand.. Whereas the diabetes pump drip feeds in insulin when the body level are too high, not based on activity.
Innovation would be great if it finally corrects a long standing problem with current blood testing relying on TSH......but not if it uses TSH as its basis & not if it doesn't account for individual differences or sets the ranges incorrectly etc.....
Personally given the current state of treatment for hypothyroidism with it illogical argument that the TSH reigns supreme & the thyroid is a simple feedback loop system I don't think such a system would be designed well so wouldnt work well! Lol.....
I have now found it thank you.
i don't think there ever was a research article as such . I think it was just that bit of technical information about the pharmacokinetics.
I thought the rest of what he wrote on the original post was his explanation of what that info meant .
I understand now tattyboogle. Thank u. Am a bit confused by it tbh....as per my reply to Helvella. Maybe I'm just being dense....lol. 🙄
Indeed....but he is also a research scientist doing research into hypothyroidism....
does this help ?
healthunlocked.com/thyroidu... at-last-comparison-of-lt4-v-dte-ndt-treatment-of-hypothyroidism
edit .. oh... perhaps not .. that wasn't the one i was looking for . soz.
Thanks....but that's measuring Ft4 levels in both products. Wait a minute am jumping between to different post threads! 🤣
waveylines,
Try this one ... pubmed.ncbi.nlm.nih.gov/875...
Thanks Radd.....is this with regards to the differences with ndt & synthectic thyroid hormones? It's a bit tech for me......but it didnt seem to be reading it as non scientific person.....but that might be my poor science knowledge. 😊
Thanks I have now read it.
Buying NDT
ndt/pregnancy
NDT and Levo combination 
Ordering NDT - a right pain!
