Carbimazole for Hashimotos, does anyone have an... - Thyroid UK

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Carbimazole for Hashimotos, does anyone have any experience?

nataliem19 profile image

Hi everyone,

I have had hashimotos for around 5 years now and have been taking Armour thyroid (previously Nature). My levels have been balanced since taking the medication, however 3 weeks ago I had the moderna vaccine and subsequent racing heart (100-120 resting). I have attended hospital several times due to my heart rate and the doctors now think it is my thyroid levels. I got a blood test in March that confirmed I was over and I reduced my level by a third (I normally take one grain in the morning snd a half at lunch so reduced to two half grains). I felt much better, then had the vaccine and started to struggle with a racing heart.

After many tests I was told to stop all thyroid medication, which I did and the levels have come down but are still above the normal range. I spoke to a specialist nurse today who wants to start me on 20 milligrams of carbimazole to speed up the process. Has anyone heard of this before for Hashimotos? I’m obviously terrified it further destroys my thyroid and I go back to hypo and feeling horrendous. Any advice would be much appreciated!! Thank you all in advance!

Blood levels March 2021 - I was on 1.5 grains a day at this point

Tsh - 0.01

T4 - 50 (range: 11 - 22)

T3 - 23.9 (range: 3.1 - 6.8)

Antibodies - 267

25th May 2021 (post vaccine having reduced to 0.5 twice a day but ended up going to A&E with a heart rate of 169 beats per minute. When I received these results with advice from the hospital I stopped all medication)

Tsh - 0.01

T4 - 58 (range: 11 - 22)

T3 - 28.5 (range 3.1 - 6.8)

8th of June 2021 (two weeks after dropping all medication)

Tsh - 0.01

T4 - 37 (range 11 - 22)

T3 - 11.8 (range 3.1 - 6.8)

Thanks everyone!

27 Replies

To me, thoseT4/3 levels from March ( before you even had the vaccine) look far too high to be explained by just taking that dose of NDT... so i suspect the real problem is your own thyroid has started making too much T4/3 for some reason.

This seems to be confirmed by the fact that even when you reduced/stopped NDT the levels are still way too high .

Carbimazole does not damage the thyroid . it simply gets in the way of it making any more T4 or T3.. the higher the dose of carbimazole the less T4/3 your thyroid is able to make... when you reduce the dose of carbimazole the thyroid is able to make more again.

So you don't need to be concerned that taking it well leave you permanently Hypo.

I don''t know why this might be happening to your thyroid hormones . and i have read some reports of some Covid vaccines having effects on thyroid levels , but in your case it seems fairly obvious that whatever is happening was already happening before you had the vaccine.

How do you feel at the moment ?

Thank you so much for your reply Tattybogle! I was really worried the medication would permanently damage my thyroid hence my concern in taking it! I agree it seems that something has happened and maybe my thyroid started doing something for once 😂

I feel pretty awful to be honest, the beta blockers are helping but not fully and so I get easily exhausted and breathless.

I’ll start on the medication tomorrow. Many thanks again for your reply!

If i was in your position , i'd take it too ... 20mcg is not a massive dose .. looking at other posts on here they sometimes start at 40mcg and then come down to 30 /20 etc.

I think sometimes it is given in 2 doses split AM and PM to help even out the effect , but it' s not something i know much about , other than from what i read in posts on here.

Hopefully other people who have taken carbimazole will come along.

but for now it seems important to get your t3/t4 levels down, while they try and figure out what has caused it ..

presumably they should check for graves disease antibodies (TRab) Thyroid Stimulating Hormone Receptor antibodies?

It's VERY unusual to go hyperthyroid with Graves after you have Hashimoto's first , but it's not impossible.... overlooked-how-many-hashimotos-patients with TSH-Receptor antibodies? the-spectrum-of-thyroid-autoimmunity/ the-spectrum-of-thyroid-autoimmunity/2/

Edit *

I do agree with PurpleNails and greygoose's concerns though.. ..they need to be monitoring your bloods frequently on the carbimazole , because we don't know the cause of your high T4/3 yet ,

And IF your levels are going down naturally and this recent period of too high T4/3 was just due to a very big hashimoto's swing (rather than continuous over production from eg. Graves or a nodule) , then carbimazole could result in low T4/3 levels fairly quickly if they weren't keeping a good eye on them.

greygoose profile image
greygoose in reply to nataliem19

I agree it seems that something has happened and maybe my thyroid started doing something for once 😂

That doesn't happen. You are hypo. you've been taking thyroid hormone replacement because the Hashi's has damaged your thyroid to the extent that it can no-longer make the necessary hormone itself. Thyroids cannot regenerate, so it's not suddenly going to start making too much hormone. It can't.

On the other hand, an immune system attack on the thyroid could have caused the dying cells to dump their stock of hormone into the blood, causing your levels to suddenly rise sharply. That's how Hashi's works. And Carbimazole can't do a thing about that.

nataliem19 profile image
nataliem19 in reply to greygoose

That’s really interesting Greygoose, I haven’t heard of a hashi’s hyper swing before and going by the treatment recommended maybe neither had the person I spoke to. Would you suggest waiting it out on my medication to see when it comes down? I’ve got repeat bloods from the hospital but I can do more frequent private blood tests too.

greygoose profile image
greygoose in reply to nataliem19

I would suggest stopping your NDT until you start to feel a bit hypo again, and then resuming it. That's what one normally does with Hashi's.

It wouldn't surprise me at all if the nurse that suggested carbimazol has not idea how Hashi's works. Certainly very few doctors know anything about it. But, surely, if you've been reading on here for any length of time, you've come across discussions on Hashi's before. You know that Hashi's is an autoimmune disease, yes? And that the immune system slowly destroys the thyroid until it is completely dead? Well, the swings are all part of the destruction process.

nataliem19 profile image
nataliem19 in reply to greygoose

Thank you Greygoose! Yes I’ve been on here for years and have read lots of Hashis, it is the only resource that really helped when I was first diagnosed. The medics could learn a lot by doing the same! Can I ask one more question, once my thyroid levels are back in the correct region, how long will it normally take for my heart rate to come down? Many thanks!!

greygoose profile image
greygoose in reply to nataliem19

I'm sorry, I can't answer that question. It probably depends on the individual - most things do. :)

nataliem19 profile image
nataliem19 in reply to greygoose

Thank you anyway!!

greygoose profile image
greygoose in reply to nataliem19

You're very welcome. :)

Don't you think you could just be having a Hashi's 'hyper' swing? Do you know how that works?

If that's the case, Carbimazole is not the right treatment. Your thyroid is not over-producing, so taking the carbi will stop it making what little it's capable of making, but it won't get rid of the hormone that is already in the blood. That has to be used up/excreted in its own good time. But, once it's gone, if you're still on carbi, you will become very hypo very quickly. Personally, I wouldn't take it.

What type of antibodies have been tested? The ones you posted above don’t specify, were they TPO? Assume they are well above limit <negative level.

You should have TSI or Trab as these antibodies help diagnose If you have a autoimmune causing continuous hyper (Graves).

Otherwise this could be a transient rise associated with hashis.

I have a over producing nodule and my levels were not as high as yours recent ones but they had been above range & slowly rising for over 4 years.

I began on 20mg carbimazole. 10mg 2x daily. Splitting dose helps reduce the production more evenly. Taking 1 dose is safe but leaving a wider gap between doses allows a window to start producing more hormone.

Once the levels are under more control a single dose is all that’s necessary.

It lowers production of new hormone, not existing levels. These have to used & the adjusted level won’t become evident until later. (Up to 8 weeks).

I wasn’t retested for 2 months, (due to consultant / GP confusion) by which time my levels were low in range & the dose was halved.

I’d agree to take a 20mg dose, but see if they will prearrange to retest you around 4 weeks later. 6 weekly is standard but as the cause of your hyper levels are not yet explained you need an earlier blood test to make sure the levels aren’t naturally dropping. As you had previous diagnosis of hashi this is possible. In which case the carbimazole will hasten the drop too far too fast.

Thank you PurpleNails! That is good to know too, can I ask do you have hashis? Yes my main concern is that by taking Carb it destroys what little I have left of my thyroid and it really affects me in the future. I’m sorry to hear you waited so long for a blood test, it’s just ridiculous!!

I have no apparent thyroid autoimmune. I had negative TPO & TRab many years ago, negative TSI at diagnosis (two years ago). I’m due to have TSI repeated as I have eye issues but the endocrinologist said it can’t be related unless I have thyroid antibodies. I also had uptake scan confirming hyper nodule. It’s 5 cm so quite a size.

I’m under investigation for possible other autoimmune, after a salivary gland inflammation. (I say it’s carbimazole induced, as the leaflet list is as side affect but every doctor I spoken to says it not the case?). Doctors aren’t doing much else, not even had blood tests, Just planning a duplicate ultrasound scan.

I can confirm carbimazole doesn’t damage the thyroid in any way. It works by inhibiting the production of new thyroid hormone.

The medication works very quickly, (within hours) but the affect on the levels can take up to 8 weeks to completely manifest as it altering the production of new levels not the existing levels which are yet to be metabolised by the body.

Not taking enough carbimazole the thyroid levels remain high.

Taking too much means the levels eventually fall too low, you become carbimazole induced hypothyroid. (Temporarily). Adjusting the medication with careful monitoring to ensure you stay in range very important.

Damage the thyroid resulting in permanent hypothyroid can occur from other reasons.

1. the patient either never had Graves but instead had a hyper phase of autoimmune thyroiditis, (or both Graves & thyroiditis) & the autoimmune attacks has resulted in the hypothyroidism.

2. The carbimazole was taken but the hyperthyroidism didn’t resolve and final treatment was given. Either RAI or Surgery. These resulted in permanent hypothyroidism.

Many associate carbimazole with the permanent hypothyroidism but this is inaccurate, the link is indirect.

Thanks Purple Nails!! What a nightmare you’ve had! I hope you get answers soon and you can get some piece of mind! I think I fall under the first category and this is all linked to Hashis rather than graves. I’m going to go for a second opinion and hopefully that will make things clearer. Thanks again for your response!

Hello 👋Did you have the moderna booster in the end hun xx

nataliem19 profile image
nataliem19 in reply to Kisca

Not yet, it will be late July before I’m offered it so hopefully things will be clearer by then!

Liyaelize profile image
Liyaelize in reply to nataliem19

I was in hospital twice. Still struggling with high heart palpitations. Very hyper. Propanol not working for me. Been nearly three months for me. Can only see endo in July. I'm also in the USA. Lost a lot of weight too. Tired and body aches are bad ww

nataliem19 profile image
nataliem19 in reply to Liyaelize

How awful I’m so sorry to hear that!! It is basically identical to my symptoms too. Do you have Hashimotos? Were you quite balanced before? What are you thinking about the second vaccine, will you get it done?

Liyaelize profile image
Liyaelize in reply to nataliem19

Have Hashi too

Kisca profile image
Kisca in reply to nataliem19

Did the palpitations happen straight away after injection hun or a few days after? Xx

nataliem19 profile image
nataliem19 in reply to Kisca

A few days after, they just got worse and worse and maxed out about 175 beats per minute. Have you had your vaccine?

Kisca profile image
Kisca in reply to nataliem19

Bless you....I had my first moderna injection a few weeks ago and felt a panic feeling come over me like a pressure in my head really other side effects other than swollen lymph nodes under armpits xx

I bad the same experience with the Moderna Covid-19 vaccine

nataliem19 profile image
nataliem19 in reply to Liyaelize

Really? What happened and how long did the symptoms last?

I had both. Am not sure if I want to have the booster shot as it's a third shot. Moderna applied for approval. How on earth do you rid the body of the excess hormone? Have Hashimoto.

nataliem19 profile image
nataliem19 in reply to Liyaelize

Wow that is good to know that someone else is having the exact same reaction but I’m so sorry you’ve had to go through it. Are you seeing any improvement in your palpitations? Did you react after the first or second vaccine? It is so hard to get rid of the excess when you can’t exercise because of the high heart rate!

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