Continuing on Carbimazole despite being in range?

[nataliem19]

Hi everyone,

I am looking for a bit of advice if possible. A few months ago I had an imuno response to the Moderna vaccine and despite having Hashis for years, my thyroid levels went out of control (T4 - 70, range 11-22) and my heart rate went through the roof resulting in several hospitalisations. My endo put me on Carbimazole (20mg daily) and I immediately stopped taking my usual Armour dose of 1.5 grains a day. My levels are now in range however my endo would like to keep me on Carbimazole for another 4 - 6 weeks albeit on a reduced dose (20mg every other day) before testing my bloods again.

To muddy the waters, during the time my levels were at their highest an antibody test for Graves came back positive. My endo still thinks the swing was caused by the vaccine and said that there is a small possibility the test was a false positive, although normally the tests are accurate. Has anyone ever heard of this or experienced it?

I know endos often keep patients on Carbimazole for long periods of time but as I am in my mid 30s I would like to conceive in the next year and so we agreed I could come off it much sooner than the normal time period (I believe a year to 18 months is quite standard). Plus I have never struggled with being over before so he thinks it is unlikely I will have a relapse.

My worry is I already feel under so I am terrified that I will go massively under and it will take months to get back to a normal range. Does anyone have any experience coming off Carbimazole? Any advice would be so appreciated!!

For reference my levels at their peak were:

15th June 2021

TSH - 0.01

T4 - 70 (range 11 - 22)

T3 - 21.7 (range 3.1 - 6.8)

Started on carbimazole on the 19th of June.

30th of June 2021

TSH - 0.01

T4 - 56 (range 11 - 22)

T3 - 18.4 (range 3.1 - 6.8)

12th of July

TSH - 0.01

T4 - 33.3 pmol/L (range 11 - 22)

T3 - 8.7 pmol/L (range 3.1 - 6.8)

24th of July

TSH - 0.01

T4 - 34 (range 11 - 22)

T3 - 8.2 (3.1 - 6.8)

1st of September

TSH - 0.01

T4 - 17 (range: 9- 21)

T3 - 1.8 (range 0.9 - 2.4)

Many thanks everyone!

[PurpleNails Administrator]

Taking 20mg alternate days is not a regimen I’ve come across, but reducing the dose often by half is very expected. Higher initial dose to halt the rising of levels then adjustments to keep in range. carbimazole doesn’t reduce the existing or current thyroid levels in your system. It works by reducing production of new hormone. Which means medication taken now will affect levels later on not immediately.

They do produce 10mg pills, I wonder why your endo has recommend a greater spaced out dose. There’s a wide 48hr gap for your thyroid to start producing between doses.

Which Antibodies were tested? There are several different types and doctors often say a particular antibody confirms Graves when it is not unique to Graves they base it on low TSH.

[nataliem19 in reply to PurpleNails]

Hi PurpleNails thank you very much for your quick reply. That is reassuring to know, I think the every other day advice was because I still have 20mg tablets left. I am just very worried I go very under and feel terrible. I don't know which antibodies were tested unfortunately but I do know my TSH is very suppressed at 0.01.

[Batty1]

I take immunosuppressive drug and it definitely causes issues with my thyroid level… so I wouldn’t discount moderna or any other Covid vaccine ability to upset your thyroid levels temporarily and some people are more sensitive.

[nataliem19 in reply to Batty1]

Yes that is what my endo said, it was quite a shock really as I had no idea it would affect my thyroid but I think I was just unlucky!

[Michoue25]

Hi Natalie, am kind of being the same situation as you. Took carbimazole 15 mg a day my T3 ( from 7.9 to 5.0)and T4 (from 24.8 to 15.6) went down drastically but my TSH still 0.02. I am not sure what does that means in medical opinions as I am still waiting for my endocrinologist appointment which is not due until two weeks time. I would like to ask you if you ever suffer from dizziness or lightheaded with that trend in your hormone level ?

Thanking you in advance

[PurpleNails Administrator in reply to Michoue25]

Please start new post so we can help in more detail.

Tell us how long have you been taking 15mg carbimazole and the cause of your hyperthyroidism.

Dose adjustments should be by FT4 & FT3 doctors sometimes only look at TSH and force it to respond by lowering levels by too much. The TSH can be very sluggish, especially if hyper for a period of time. Sometimes the TSH remains unreliable long term. Referred to as hypothalamus–pituitary–thyroid (HPT) axis down regulation.

Ensure you put the range with any results. Ranges vary between labs.