Stopping carbimazole - any side effects? - Thyroid UK

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Stopping carbimazole - any side effects?


Hello all, I have an overactive thyroid (Grave's disease), was diagnosed July 2017 after 6 months of awful symptoms. Been on a relatively low dose of Carbimazole (now on 5mg) and now I am becoming hypo - my GP says I'm still in normal ranges but I feel the difference, I am exhausted all of the time. Off to conduct field research in the tropics and I'd rather be hyper than hypo as I work 14 hours a day and need to not fall asleep every time I sit down. I don't have an endo appointment until June, and I know from my blood test results that I went to hypo within a month (which means of course that my thyroid may have bounced back to normal and I am overmedicated) so I am worried that with 6 weeks of Carbimazole may make me pretty hypo. I am considering taking myself off of Carbimazole now (which we had discussed for sometime this year anyway).

My question is: are there any nasty side effects coming off it, apart from the obvious return of hyper symptoms? I get terrible headaches and migraines anyway (pretty sure they got worse when I started Carbimazole, worried that now I'm used to it they might get bad again).

4 Replies

Sounds really exciting !

Not withdrawal symptoms as such, but there is obviously a chance that you might not achieve remission. I assume you are on titration (Carbimazole only) rather than B&R (carbi plus levo) ? Rather than stopping altogether, you could try reducing to 2.5mg/day (you need the 5mg tablets for this, dividing 10mg tabs into 4 will probably leave you with a load of crumbs !) Some people here are on 2.5 mg every other day, so you can go quite a bit lower before coming off altogether.

I would phone the endo’s secretary, and see whether you can get at least a phone consultation, and ideally, a new set of bloods before you go. Are you confident that you can distinguish between hyper and hypo symptoms ? Maybe try making a list, and seeing how confident you are in each case. You could then suggest to the endo that you titrate yourself according to your symptoms, and within an agreed range - eg max 5mg, min 2.5mg every other day. You would need to take enough carbi with you for the max dose for the whole of your stay. Bear in mind that many of us find stress can make our thyroid levels rise - this may not be the best time to come off Carbimazole completely, or at least to be without a supply .

You need to declare Graves’ to your travel insurer, and unfortunately, it will probably result in additional premium

Will you need additional vaccinations ? Might be worth mentioning these to the endo as well .

Sounds like your treatment is progressing well ! By the way, was your Graves’ confirmed with antibody tests ?

So I wondered how people got 2.5mg, it is from splitting the pills? Yeah just Carbimazole for me. I called the secretary and left a message to call me back or email me if I am away. I just had blood tests last week and the GP confirmed that my levels have dropped, but they don't know much about these things I have realised. I am really sensitive to any changes, when I had horrendous hyper symptoms last year (in the field, hence 6 months of no diagnosis) my levels were only a little too high, so I know that if I am a little too low then I will feel it, and I am sure I am feeling it now, as all my vitamin levels are fine.

Also, confirmed as Grave's disease with tests last year (I paid to go private for initial consultation as NHS couldn't see me for 4 months) so I got all the tests for my £200!!!! I already declared my Graves' to insurer (its a PhD project so I'm covered by university insurance which is awesome!) Vaccinated to the hilt already too...


Suggest you get full testing of thyroid and vitamins now before you go abroad

For full Thyroid evaluation you need TSH, FT4, TT4, FT3 plus TPO and TG thyroid antibodies. Plus vitamin D, folate, ferritin and B12.

Essential to test thyroid antibodies, FT3 and FT4, plus vitamins

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should ideally be done as early as possible in morning and fasting. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

(If you were on Levothyroxine, don't take in the 24 hours prior to test, and if on T3 don't take in 12 hours prior to test, delay and take straight after)

If TPO or TG antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's. Low vitamins are especially common with Hashimoto's. Food intolerances too, especially gluten. So it's important to get tested.

Hi there i hit hypo in december on 5mgs of carbi and i just lowered the dose myself as silly endo wanted to keep me on 5mgs when my levels were hypo, but bear in mind that the new dose will take a good 4 weeks to settle. I have a pill cutter to split my pills. Not a good idea to not take anything as you need to titrate down. Good luck.🌟

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