Re: blood test and stopping thyroid

[Guest guest]

,

Wrong context. We were talking about withdrawing for a whole week. That

cuts T4 in half. One day reduces it by 9.5%. Two days is an 18% drop,

which I found rather uncomfortable, since I was on a full replacement

dose. If you still have partial thyroid function, your gland will work

overtime to keep up, so you could go a lot longer without noticing. For

someone with NO thyroid function, a day's delay before testing will

certainly change T4 and T3 a little, but TSH responds too slowly for it

to be affected.

The curve is not linear, but exponential. In one half life, half is

gone. In two half lives, 3/4ths is gone. In three, 7/8ths. And, so on.

Mathematically, since the T3 has the shorter half life, it is in secular

equilibrium with the T4, which means it decreases according to the half

life of the T4. The T3 half life only applies if the supply from T4 is

cut off. This happens if you take nothing but Cytomel.

The exponential decay curve also governs the temperature of your coffee

as it cools off, something called Newton's Law of Cooling. Hot beverages

cool a lot in the first few minutes but will stay at least a little warm

for a fairly long time. The form for both phenomena is exp[-t/T1/2 ln2]

Chuck

You wrote:

>

>

> Okay; you've really thrown me for a loop here. I had assumed that with

> a half life of a week that T4 would probably not be reduced in one day

> much more than 10% or maybe 15% [a guess] by the morning after the day

> in which a dose was taken. I had further assumed that with 90% of your

> normal T4 left it would continue to produce about 90% of the T3 needed.

> Your post indicates I'm out in left field [again]. Could you please

> explains what actually happens? Is most [or a lot] of the T3 reduction

> due to the panic mode you mention? What does the reduction curve of

> serum level T4 look like; is in not linear?

>

> Thanks,

>

>

> > Have you ever tried that? Two days without meds made me quite ill. Since

> > the half life of T4 is about a week, that means your SUPPLY of T3 is cut

> > in half. It is actually cut by more, because the endocrine system goes

> > into panic mode to conserve the T4 supply. The amount of T3 needed to

> > maintain a euthyroid state is rather delicate. Cutting the supply in

> > half makes a dramatic change in how you feel. Even cutting it by a few

> > percent can make you ill.

> >

> > As you say, we are even more sensitive to a cutoff in T3.

[Guest guest]

,

You wrote:

>

> ... Do you know if the way you respond to stopping T4 is fairly typical of

> the average patient?

I would expect it to be typical of someone with no thyroid function left

and fully titrated. During titration, the half lives will be longer,

which is one reason why they like to make incremental changes in dose,

especially if there is an existing cardiac condition.

Chuck

[Guest guest]

Chuck - for anybody starting T3 for the first time in their lives - either synthetic of natural, then it is safest to recommend they split their dose to start with so they don't take too much at one go and they can share the T3 out throughout the day - if after that, they want to try it all in one go then great - we have many on this forum who do just that.

Sheila

I used to recommend that too, but I have since run into people that don't split the T3 and still don't experience a slump.

..

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[Guest guest]

Val,

You wrote:

>

>

> I phoned Forest to see the half life of the T4 & T3 re armour & was

> told that the T4 has a half life of 6 to 7 days generally, if hyper 3

> to 4 days and if hypo 9 to 10 days, T3 has a half life of less than or

> equal to 2 days in all cases.

>

> So I would guess that the half life will vary a lot for individuals &

> this is why some need to take meds much more often than others.

That is why I was careful to specify the average half lives were for the

euthyroid condition. Most of us on medications are at least close to

being euthyroid, so we will be close to the average. There should not be

much variation in dosage timing.

While I can agree with T3 always being less than 2 days, I have also

never seen a reported value less than 1 day, certainly not 8 hours. So,

with Armour, no one should need to split doses, although some may prefer

that, depending on the time(s) of day when they are most active. Cytomel

may be different.

Chuck

[Guest guest]

,

You wrote:

>

> Think I said in a previous mail, had been on 150mcg for 6 weeks and then

> 175mcg for a week, I say overloaded because thats all I can think it

> was,...

Sorry if I missed that in the earlier post. I'm on way too many lists!

Anyway, all four hypoT women in my family have been on at least 200 mcg

of T4 at one time. One of them has now mixed some Cytomel with that.

But, your description says that you had not yet reached equilibrium in

the titration process, so the relatively low doses that " overloaded " you

make it seem very likely that you still had some thyroid function left.

If so, then the 6 weeks on 150 mcg gave your gland a rest, just like

Sheila's story, so the gland was able to contribute again, when the

medication was cut off. If you have Hashi's, this sort of restoration of

function is not at all unusual.

Chuck

[Guest guest]

Hi

Its definately a physical response I get.

Chris

>

> I don't know how easy it would be to tell a psychological

addiction from

> a physiological one. In the latter case you have a physical

response

> that tells you that you need the medication, while in the former

case

> your body generates some symptom that tells you that you need it.

I

> think...

>

> In any event, I suspect there's a psychological element involved

in a

> LOT of our medications that we seldom if ever suspect. For

example: I

> read recently of a group of males who were given a placebo but

told it

> was chemo. 30% of them lost their hair...

>

>

> .

> .

>

> >

> >

[Guest guest]

Thanks Chuck but I dont agree, I now know for sure that my adrenals were the culpit in all this, they could not cope with the increase after increase of T4. Adrenals play a VERY BIG part in all this and if they are not adequaetly equipped to accept and deal with the sudden addition of T4 you WILL NEVER FEEL WELL and infact you can feel worse.

Adrenals MUST be treated first, if they are weak, before the thyroid and it is thanks to this site and Dr P that I found that out after 2 yrs of not regaining my health on T4. It is now my adrenals that are 'getting the rest' and the cortisone that they so badly needed, I have the salivary results to prove how bad they were coping

> > Think I said in a previous mail, had been on 150mcg for 6 weeks and then > 175mcg for a week, I say overloaded because thats all I can think it > was,...

Sorry if I missed that in the earlier post. I'm on way too many lists!

Anyway, all four hypoT women in my family have been on at least 200 mcg of T4 at one time. Chuck

------------------------------------

TPA is not medically qualified. Consult with a qualified medical practitioner

before changing medication.

[Guest guest]

Hi Chuck

I too take 200mcg, always have done.

Chris

> Anyway, all four hypoT women in my family have been on at least 200

mcg

> of T4 at one time. >

> Chuck

>

[Guest guest]

Hi Chuck

When you say you used to recommend splitting doses - are you a

practitioner of some kind?

Leah x

> I used to recommend that too, but I have since run into people that

> don't split the T3 and still don't experience a slump.

[Guest guest]

You wrote:

>

> I too take 200mcg, always have done.

>

Yes, it's the common range of full replacement for T4. Armour seems a

lot more variable, from what I have run into. My point for was

that she had not reached a full replacement dose or equilibrium, so her

extended period without medication or adverse effects from it was not a

fair comparison, whether adrenals were involved or not.

Chuck

[Guest guest]

Hi Chuck

I think I understand. So is it because of my dose that if I forget

to take it I feel bad straight away.

Chris

> >

> > I too take 200mcg, always have done.

> >

>

> Yes, it's the common range of full replacement for T4. Armour

seems a

> lot more variable, from what I have run into. My point for

was

> that she had not reached a full replacement dose or equilibrium,

so her

> extended period without medication or adverse effects from it was

not a

> fair comparison, whether adrenals were involved or not.

>

> Chuck

>

[Guest guest]

I really dont know how you know that I had not reached my optimim replacement level Chuck, you cannot possibly know that, have you seen my last lot of blood tests or something? My last TSH result was 0.66 and my T4 18.1 with 22 being the cut off point, I dont rely to much on results these days, its how someone feels and I can tell you know that 150mcg of T4 did not make me feel well, HC does! Yet again we all are different and just because 200mcg is a full replacement dose for one person does not mean it will be for everyone and when I took 175mcg for a week I had symtoms of going hyper

> > I too take 200mcg, always have done.

> Yes, it's the common range of full replacement for T4. Armour seems a lot more variable, from what I have run into.

Chuck

------------------------------------

TPA is not medically qualified. Consult with a qualified medical practitioner

before changing medication.

[Guest guest]

Re: Re: blood test and stopping thyroid

Hi Chuck

Just wondering what your background is - we're all ready to learn from one another here - and if you have specialist knowledge such as medical or pharmacy then it would be good to know that.

thanks,

Gill Yes, it's the common range of full replacement for T4. Armour seems a lot more variable, from what I have run into. My point for was that she had not reached a full replacement dose or equilibrium, so her extended period without medication or adverse effects from it was not a fair comparison, whether adrenals were involved or not.Chuck

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[Guest guest]

Leah,

>

> When you say you used to recommend splitting doses - are you a

> practitioner of some kind?

No, I meant I recommend it informally, on discussion lists. I am

involved in biomedical research, but nothing to do with the thyroid.

Since doctors often prescribe barely enough thyroid meds to do the job,

spacing out the doses always seemed to me like a reasonable way to

stretch the prescription and solve other problems. There has been a lot

of ruckus raised about T3 meds " spiking " the blood levels. One effect is

this drives the TSH down artificially. This is why I said before that an

8 hour half life for T3 was ammunition for the BTA. If it really were 8

hours, that would make the spiking effect even more pronounced.

However, as the measurements of T3 half life have gotten better, it has

also gotten longer. That is why Forest would say it is somewhere below 2

days. Others have pegged it at 1.5 days and most commonly around 1 day.

One difficulty is that T3 is linked to the longer T4 half life. To

measure it reliably, they have to also monitor T4 and conversion and

separate them in the analysis.

At any rate, the beneficial effects of T3 seem be to smoother than the

blood levels indicate, for many people. Also, TSH seems to be suppressed

whether the doses are split or not. So, when people ask about splitting,

it might be worth a try, at least initially, but the extra complication

that creates may not be worth the alleged smoothing. That benefit also

may not justify the extra expense of going to a compounding pharmacy for

timed release forms of Cytomel.

Chuck

[Guest guest]

That would account for the long tail and whiskers....

Sorry, couldn't resist.

>

> Leah,

> >

> > When you say you used to recommend splitting doses - are you a

> > practitioner of some kind?

>

> No, I meant I recommend it informally, on discussion lists. I am

> involved in biomedical research, but nothing to do with the thyroid.

[Guest guest]

You wrote:

>

> I think I understand. So is it because of my dose that if I forget

> to take it I feel bad straight away.

That works for me. I found missing two days sufficiently unpleasant that

I am very careful about getting every dose on time. I do the same for my

son and our ian Ridgeback.

BTW, the full replacement dose for males is generally lower than for

females, even though we have larger average body mass.

Chuck

[Guest guest]

,

It's not that you hadn't reached the optimum yet. It's that your optimum

was lower than would be expected if your thyroid were completely gone.

The doses we take are for maintenance. They sustain a much higher blood

level that is reached only after taking the incremental doses for about

six weeks (actually 10 weeks for T4, but 6 is close enough). T3 reaches

this saturation much faster, but you probably know why. (About 10 days)

Anyway, even if 175 mcg was making you become hyper, you were only on it

for one week. There must have been some reason for the increase in the

dosage from 150 mcg. That means you had not completed the titration and

were not at YOUR optimum dose yet at 150 mcg. YOUR optimum must have

been in between at best, 175 mcg at most, since you became hyperT.

Since that is less than what most people need to completely replace a

missing thyroid, it suggests that you still had some thyroid function

left. That is one of the the most common reasons why we all vary in

optimum dose, and why the optimum may change; most still have varying

degrees of residual function left, even after many years.

The difference between an optimum dose with partial function and a truly

full replacement dose is more apparent in people that have done the

radioactive ablation. They always seem to need much larger doses,

something that still sometimes surprises their doctors.

Chuck

You wrote:

>

> I really dont know how you know that I had not reached my optimim

> replacement level Chuck, you cannot possibly know that, have you seen my

> last lot of blood tests or something? My last TSH result was 0.66 and my

> T4 18.1 with 22 being the cut off point, I dont rely to much on results

> these days, its how someone feels and I can tell you know that 150mcg of

> T4 did not make me feel well, HC does! Yet again we all are different

> and just because 200mcg is a full replacement dose for one person does

> not mean it will be for everyone and when I took 175mcg for a week I had

> symtoms of going hyper

[Guest guest]

GILL,

You wrote:

>

> Just wondering what your background is - we're all ready to

> learn from one another here - and if you have specialist knowledge

> such as medical or pharmacy then it would be good to know that.

Sorry, I did not mean to provoke this question. As I said earlier, I am

not involved in any medical practice. I just have a family with a high

incidence of familial idiopathic hypoT.

I am involved in, and supervise, university research, as chair of two

departments, Chemistry and Physics, at a university in Kansas and am an

adjunct faculty at the U. Nebraska Medical Center in Omaha in the

department of Orthopaedic Surgery. That does give me access to full

papers and resources in medical research that most on the list do not

have. However, information from any of these sources may take awhile. In

my research, I have mainly applied particle accelerators to various

problems in materials science, although lately I have been working and

writing grant proposals to explore terrestrial effects of high energy

cosmic rays, particularly gamma ray bursters and the galactic boundary

shock.

I do advise and teach pre-med and pre-pharmacy students, for whatever

that may be worth. Three of my former students are now M.D.s treating

members of my family. My wife used to be a business manager for a

medical clinic, and later consulted for several large hospitals, so we

hung out with doctors a lot. My daughter has been a nurse for about a

decade. However, she still thinks the thyroid resin uptake test is the

best way to look for binding problems. I have not been able to persuade

her that FT3 is much more precise.

Chuck

[Guest guest]

Hi Chuck - please don't apologise for assuaging my curiosity!!

Your background can be very useful to people here - Bob, for example, has become a great asset and is often asked to explain further. We do have a wide range of experience here, clinicians, nutritionists, NHS managers, chemists and students etc - a number with Athens registration or subscriptions, so we are able to access the latest research (and do!) but the more the merrier - stand by your bed to do research for us!!!

The majority of people though, come here as patients, whatever their profession, and often are very ill patients who are not getting the treatment they should be on the NHS. If you can help advise and support our members you will be very welcome.

Maybe you could hold the 'debate' though?!! lol

Gill

I do advise and teach pre-med and pre-pharmacy students, for whatever that may be worth. Three of my former students are now M.D.s treating members of my family. My wife used to be a business manager for a medical clinic, and later consulted for several large hospitals, so we hung out with doctors a lot. My daughter has been a nurse for about a

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[Guest guest]

Hi Chuck

So not 'KTBoundary'?

Bob

> >

> > Just wondering what your background is - we're all ready to

> > learn from one another here - and if you have specialist

knowledge

> > such as medical or pharmacy then it would be good to know

that.

>

> Sorry, I did not mean to provoke this question. As I said earlier,

I am

> not involved in any medical practice. I just have a family with a

high

> incidence of familial idiopathic hypoT.

>

> I am involved in, and supervise, university research, as chair of

two

> departments, Chemistry and Physics, at a university in Kansas and

am an

> adjunct faculty at the U. Nebraska Medical Center in Omaha in the

> department of Orthopaedic Surgery. That does give me access to full

> papers and resources in medical research that most on the list do

not

> have. However, information from any of these sources may take

awhile. In

> my research, I have mainly applied particle accelerators to various

> problems in materials science, although lately I have been working

and

> writing grant proposals to explore terrestrial effects of high

energy

> cosmic rays, particularly gamma ray bursters and the galactic

boundary

> shock.

>

> I do advise and teach pre-med and pre-pharmacy students, for

whatever

> that may be worth. Three of my former students are now M.D.s

treating

> members of my family. My wife used to be a business manager for a

> medical clinic, and later consulted for several large hospitals, so

we

> hung out with doctors a lot. My daughter has been a nurse for about

a

> decade. However, she still thinks the thyroid resin uptake test is

the

> best way to look for binding problems. I have not been able to

persuade

> her that FT3 is much more precise.

>

> Chuck

>

[Guest guest]

Not being a scientist I'll have to leave the science to others too. But

I do have the ability to appreciate and to some small extent understand

a lot of scientific basics; although from a lay level.

Regards,

..

..

>

> Posted by: " sheilaturner " sheilaturner@...

>

<mailto:sheilaturner@...?Subject=%20Re%3A%20blood%20test%20and%20stopp\

ing%20thyroid>

> campaigner77 <campaigner77>

>

>

> Sat Aug 30, 2008 10:10 am (PDT)

>

> It's mentioned many times . I guess it depends where you are

> reading, what you are reading, and how 'scientific' the paper is.

> Here, we tend to go by how a person feels and follow the basic facts

> and leave the science to the scientists.

>

> Sheila

[Guest guest]

I guess I should have mentioned why I asked: It's because if T3 half

life is 24 hours then you have a 50% level in 24 hours, while if it's 8

hours then you only have a 12.5% level after 24 hours. I think...

..

..

>

> Posted by: " sheilaturner " sheilaturner@...

>

<mailto:sheilaturner@...?Subject=%20Re%3A%20blood%20test%20and%20stopp\

ing%20thyroid>

> campaigner77 <campaigner77>

>

>

> Sat Aug 30, 2008 10:10 am (PDT)

>

> It's mentioned many times . I guess it depends where you are

> reading, what you are reading, and how 'scientific' the paper is.

> Here, we tend to go by how a person feels and follow the basic facts

> and leave the science to the scientists.

>

> Sheila

[Guest guest]

Okay; I had the actual reduction correct but used the wrong terminology

[linear] for the curve.

Thanks,

..

..

> The curve is not linear, but exponential. In one half life, half is

> gone. In two half lives, 3/4ths is gone. In three, 7/8ths. And, so on.

> Mathematically, since the T3 has the shorter half life, it is in secular

> equilibrium with the T4, which means it decreases according to the half

> life of the T4. The T3 half life only applies if the supply from T4 is

> cut off. This happens if you take nothing but Cytomel.

[Guest guest]

Hi Chuck

What you say makes so much sense to me.

I was explaining to a GP a couple of months ago that I can feel the

differences in thyroxines i.e. for me Eltroxin is like taking 175

levothyroxine. I only ever tried Eltroxin for 3 weeks and during

that time I met a work colleague and his wife in a supermarket one

day and apparently they thought I had been drinking, obviously I

looked like I had. I do not drink, only ever have the occasional

glass of wine with a meal out and this was 11 am in the morning.

In an attempt to reduce my dose a while back I was asked to try 175

and 200 alternately. I did not know whether I was coming or going

and within a week of doing this I went to the GP and had it recorded

as to how it felt and went back to the 200. I explained then 200

seems to be the minimum dose I can take without any ill effects and

that timing also seems to be of the essence.

Because of TSH and FT4 blood tests (first time ever tested TSH <0.1

and FT4 32.6) my 200 got reduced to 150 in November 2003 after over

33 years on 200. I went incredibly hypo with an FT4 of 24 and

dreadful symptoms even though my TSH was still <0.1. Having put

myself back on 200 in April 2007 once I realised it was the lack of

thyroxine I was suffering, it has taken about 18 months to get

myself completely back to normal (normal as I know it).

I have a copy of my GP notes and I can now pinpoint on the notes

over the years when I forgot to take it by the reasons for my visits.

Chris

> >

> > I think I understand. So is it because of my dose that if I

forget

> > to take it I feel bad straight away.

>

> That works for me. I found missing two days sufficiently

unpleasant that

> I am very careful about getting every dose on time. I do the same

for my

> son and our ian Ridgeback.

>

> BTW, the full replacement dose for males is generally lower than

for

> females, even though we have larger average body mass.

>

> Chuck

>

[Guest guest]

Hi Chuck

My dog is hypo too and I do the same for her.

What you say about the full replacement dose in males/females is

interesting. I am described as a " tiny little thing " UK size 6.

Chris

> I am very careful about getting every dose on time. I do the same

for my

> son and our ian Ridgeback.

>

> BTW, the full replacement dose for males is generally lower than for

> females, even though we have larger average body mass.

>

> Chuck

>