Does taking LevoThyroxine stop your own production of thyroid hormone

[Meltedwellies]

Is that why they do not want to see zero TSH because they still want your thyroid to try to work?

[Clutter]

Cancer patients are over-replaced to suppress TSH <0.1 in order to prevent recurrence. The medication tells the pituitary to shut up and stop telling the non-existant thyroid to produce T4 (which converts in the liver to T3).

Suppression slightly increases the risk of heart arrhythmia/atrial fibrillation and bone loss.

Low doses of 25mcg may also discourage the pituitary from producing TSH which is why starter doses of 50mcg/75mcg are recommended.

[ThyroidLadyLondon in reply to Clutter]

Hi there, I just wanted to understand why a low dose may discourage TSH production?

I have just been prescribed 50mg of levothyroxine over the last couple of weeks, but have found that it made me restless, have difficulty falling asleep and my digestion has 'sped up' shall we say, after being too slow before the pills. I therefore would go some days on 1/2 a pill or no pill at all if I was feeling fine. Problem is, after taking 1/2 I seem to have side effects which are more severe than when I take the whole 50mg. The last two days I have literally almost blacked out immediately after taking 1/2 a pill and felt as if my heart was beating too slowly.

Can you shed any more light of what you meant about the 25mg dose?

Thanks in advance!

Genia

[Clutter in reply to ThyroidLadyLondon]

Zmironova,

25mcg may be enought to reduce TSH slightly but not to replace the FT4 required.

If you were prescribed 50mcg then 25mcg won't be sufficient. You need to take it daily not intermittently. Adverse effects won't usually last beyond 2 weeks.

Slow heartbeat (bradycardia) is a symptom of low thyroid hormone so you need to take the 50mcg you are prescribed.

[ThyroidLadyLondon in reply to Clutter]

Thanks for the response Clutter

I'm having a really tough time coming to terms with the diagnosis. I'm a 34 year old woman who has (albeit by my own measure) in good health all my life. I'm a good weight, I eat a healthy and varied diet and exercise moderately. The issue with the thyroid was picked two months ago, 4 months after my second baby was born, because I developed vertigo. A blood test showed everything 'normal' except the thyroid function. My TSH has gone up from 10 to 77 and then to over 100 in the space of two months and I began to take the levothyroxine. Had it not been for the vertigo I would have said that I felt mostly like I did following the birth of my first - very low energy, fatigued much of the time, dry skin, moderate hair loss. All this stabilised after about a year and a half post partum.

I'm still not clear on a) what is the difference between post partum thyroditis and Hashimotos and b) whether taking synthetic thyroid hormone will inhibit my own thyroid hormone production.

If I have a chance of recovering like I did after baby #1 (although I have no diagnosis, since I wasn't tested, just hypothysing on similar symptoms) , am I jeopardising this by taking the levothyroxine. I'm struggling to find answers to these questions..

[Milly79 in reply to ThyroidLadyLondon]

Can you tell me what the outcome of this was? Did thr levothyroxine switch off your own thyroid hormone production?

[waycoolmom1 in reply to ThyroidLadyLondon]

Hi Zmironova. Even though it's been a while since you posted this, I am just now seeing it because I was researching about Levothyroxine.

After reading your post above, I wondered if you had considered having your iodine level checked.

I hope you have recovered after baby #2.

Best wishes!

[Aurealis]

They want to see TSH in range as they regard this as a measure to indicate that you're taking the right amount of hormone for you. Whereas they regard a supressed TSH as your pituitary indicating that you're over medicated. Good theory but in practice it makes a lot of us ill - perhaps because our thyroids are underactive or inactive so don't respond sufficiently to the TSH.

[silverfox7]

Interesting question and not sure of the answer. I was told many years ago at the surgery that I would always know if I took too much Levo as my thyroid would feel painful so that suggests that the extra Levo is enough for what your body needs but your thyroid is still trying to produce it and it builds up within the gland itself. I've never questioned how or why so have no idea if that's right or not but throwing it in to see if anyone comments! Logic says that if you need more thyroxine than your body can provide that you take a set amount of Levo and let your body do the fine tuning but again don't know if it works like that.

[sallypg in reply to silverfox7]

Sounds like a good theory. I do suffer from a painful thyroid from time to time. I also change my medication whenever I feel either too low or too high in thyroxine. Just go in what message my body is giving. Last week i got a severe bout of anxiety so have cut medication by 25 to see what happens. Slept better last night so will see how it goes from here

[silverfox7 in reply to sallypg]

Yes logic tells me it is fairly sound but since I was told that we have found GP's have no idea and Endo's can be found wanting. The original post made me think of what I was told and as I've gained so much on this site I thought to add it to the mix. I have far more faith in fellow sufferers than our learned friends and their text books. I don't think the text books can put across the fact that we are all different either by symptoms or reaction to medication so I have some sympathy with the medics but only some because they won't listen and learn!

[edysia2 in reply to sallypg]

Is your thyroid hurting when you take to much LEVO? I thought it would be the opposite, if you don't get enough LEVO then thyroid would work hard to make some t4 hence pain from additional strain on poorly functioning thyroid gland ? Xx

[sallypg in reply to edysia2]

My problem started with a thyroiditis when first it went hyper, very painful. Then it went normal, felt fine. Then hypo and back to being painful. So still not sure exactly whats wrong with it, Hashis or what. Just know its uncovered my adrenal issue as well.

[shaws Administrator]

It is unfortunate that many Endos and GP's believe it is o.k. for us to have a TSH 'within range' but that may be too high for a number of us which means constant complaints, ill-health, etc etc. There is always a chance that we can also develop other more serious diseases.

As people with cancer of the thyroid gland have to have a suppressed TSH, it doesn't make sense to me that those who dont cannot have enough thyroid meds to have a low or surpressed TSH. Dr Toft of the BTA also says this in an article. Just a pity most doctors are unaware that some of us need a very low or suppressed TSH.

[sallypg in reply to shaws]

I seem to function quite well on high TSH. Mine was sitting at around 18 but i didnt feel that bad. Nowadays I can barely function on 5 but think the problem is adrenal as levo puts adrenals under pressure

[Glynisrose]

It is a fantasy invented by doctors that thyroxine causes any sort of heart or bone problems, NOT taking any or not taking enough will do that!!! I am on NDT prescribed by my endo, he regularly tries to reduce it based on blood results but I never agree!! I did ask once why I would need TSH if I have no thyroid and was threatened with discharge from his clinic!!

[sallypg in reply to Glynisrose]

Seems very rare your endo prescribes you NDT

[Glynisrose]

So logically if cancer patients (who have had their thyroid removed) don't need TSH then why does anyone who has no thyroid?

[Meltedwellies]

Thank you very much for your replies, very helpful.

I fail to see how the gland can be expected to function side by side with 'top-up' hormone, as the more one takes the less TSH stimulates production (if some thyroid tissue is remaining). The resulting full dose seems inevitable and thus reason for 'free' scripts. M