Does any one know how long it takes for levothy... - Thyroid UK

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Does any one know how long it takes for levothyroxine to leave the body once you stop taking it?

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roslin profile image
roslin

I found this

Thyroxine has a half life of 6-7 days

What does this mean.. if you are normal it takes 6-7 days after ceasation of hormone treatment to drop to 50% blood concentration after equilibrium was achieved.. then another 6-7 days to reach 25%.. and another week to reach 12.5%.. etc.

Apparently it also depends on individual blood chemistry

Roslinxx

Ansteynomad profile image
Ansteynomad

About six weeks I believe, overall.

AN

rosetrees profile image
rosetrees

That seems to be one of those odd questions that has a variety of answers.

This en.wikipedia.org/wiki/Levot... says 9 - 10 days half life if you are hypo (it's in the info box on the rhs)/ Which would mean around a month to get down to around 10%

This australianprescriber.com/ma... says:

"The half-life of thyroxine in euthyroidism is 6–7 days. This is reduced to 3–4 days in hyperthyroidism and prolonged to 9–10 days in hypothyroidism. Thyroxine has a full therapeutic effect 3–4 weeks after starting treatment and will continue to have a therapeutic action for 1–3 weeks after treatment stops."

cein profile image
cein

Dont know anything technical or anything related to half-life etc; sorry .......... But I was told this a couple of months ago ... when the chemist couldn't get hold of my Eltroxin first time around they told me ... you will be ok without them for about 10 days ... and it would be good for me to remember this incase I ever went on holiday and forgot to take them with me.

helvella profile image
helvellaAdministratorThyroid UK in reply to cein

In my opinion, the chemist who said this was irresponsible and wrong.

Although I have seen this said many times, it is patently not the case. It might be true that few (if any) have died from not taking levothyroxine for ten days, but you can see some people start to suffer after a day without. I think I notice when I skip my usual dose prior to a blood test.

Rod

cein profile image
cein in reply to helvella

Thanks Rod,

I thought it was a bit strange because I have been told for many years in the past not to run out ( my memory added to being busy :-) ) and the pharmacy have loaned me a few from my forthcoming perscription until it arrives.

joannec123 profile image
joannec123 in reply to helvella

Im glad you have said this, my gp has made me stop my levo, only 25mg. I stopped taking it 4 days ago and today feel terrible, she said it would take a month...

helvella profile image
helvellaAdministratorThyroid UK in reply to joannec123

Ah! So your doctor thinks it is fine that you would feel terrible in a month?

GPs seem to know nothing of these things. It would take of the order of a month to six weeks for your TSH level to stabilise after a change. But by far the majority of the change of actual hormone levels occurs early on.

Rod

joannec123 profile image
joannec123 in reply to helvella

I think I need to see an Endo to be honest. I feel terrible already and she wants me to see her in 3 months! I have made an apt for tomorrow morning, but suspect she will say no way could I be feeling poorly already and that my hoarse throats a virus... :-( we will see

Theresa124 profile image
Theresa124 in reply to helvella

Hello. I only took the levothyroxine for two days. That was the beginning of November 2016 it now December 31 and I feel like crap. I also take other meds but I thought the levothyroxine would of stopped with the brain fog and headaches and all that by now. What do I do?

helvella profile image
helvellaAdministratorThyroid UK in reply to Theresa124

Your response here, on a three-year-old thread is very likely going to be missed.

I suggest you write a brand new post explaining a bit more and asking what you want to know. Far more likely to get useful responses.

joannec123 profile image
joannec123 in reply to helvella

I did notice if I was even late one day with just the 25mcg! so now I am suffering a week later, and also have lost my voice!!

DrHafez profile image
DrHafez in reply to helvella

This post is old... Does this still true.  Why you said they will die if not talking levothyroxine for 10 days... This makes me scared because I will start medication with low does 12.5 micogram (where my TSH is subclinical 5.9). But I feel cold most of the time and have pain in my foot & hands. My GP told me to start the medication as above.

Thanks

helvella profile image
helvellaAdministratorThyroid UK in reply to DrHafez

I find it difficult to believe it is ever sensible to start on 12.5 micrograms.

Very low doses of thyroid hormones appear to reduce the output of the thyroid more than they themselves contribute. So they can result in the patient becoming more hypothyroid.

Usual starting dose is 50 micrograms unless there is a special reason to do otherwise. Then 25 micrograms is often used.

For most people, going without levothyroxine for a few days is no worse than unpleasant. Some people seem much more quickly affected by this than others.

Death from lack of thyroid hormone is very rare and usually takes a very long time. Prior to there being any treatment at all for hypothyroidism, they used to talk of twelve years from initial problems to death. And over that sort of time, at least some would have died of something else first.

smschusta profile image
smschusta in reply to DrHafez

You must take thyroid meds only if your thyroid has been removed or destroyed with radioactive iodine. In this case it's very dangerous to not take your medication. Otherwise going off meds shouldn't kill you just make you feel terrible if you are hypothyroid. Many people do better on armour or naturethroid because they have t3 in them and many cannot convert t4 to t3 making them still feel sick on levothyroxine/synthroid. I am weaning myself off my thyroid meds right now and so far feel better than when on them but that's why I checked this thread to see how long it would take to clear the t4. I have been on naturethroid and levothyroxine combo.

roslin profile image
roslin

I was told that if you have normal thyroid and took a dose of thyroxine it would peek at 10days and then go down again. it seems very complicated.

Roslin

Heloise profile image
Heloise in reply to roslin

Do you mean if you take it daily for each of ten days and then it peaks? That sounds about right. If it drops 50% in 6 or 7 days, depending on how soon it begins to be incorporated into the bloodstream it then starts to drop by a certain per cent soon after and continues until it is totally out of your system. That's why you need to take it daily until you get to the saturation point your body needs. You keep adding T4 and keep losing it as well. I've been trying to find a good explanation of this.

moonbeam001 profile image
moonbeam001

I disagree entirely. I have taken 100mg of levothyroxine for 5 years.

I lowered mine, from 100mg to 50 mg Apart from 1 off day I am feeling great. I have been off 100mg of levothyroxine for 2 weeks now and taking just 1/2 a tablet.

I really feel happy. I realise its early days, but after a month has passed, if I am still feeling good I will lower carefully again, 25mg one day and maybe 50mg the next.

No hoarse throat, no great aversion to the cold, just feel normal.

Genie55 profile image
Genie55 in reply to moonbeam001

Can u tell me why you decided to stop and have u been successful. 

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