Can I stop taking Carbimazole?: In May 2022 I had... - Thyroid UK

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Can I stop taking Carbimazole?

Oona129 profile image
16 Replies

In May 2022 I had a blood test, requested from my GP because I was feeling exhausted. The result showed a TSH level of <0.01. I was immediately put on 20mg per day carbimazole and referred to an endocrinologist. TSH off the bottom of the scale indicates hyperthyroid. All subsequent blood tests showed TSH, T3 and T4 in the normal range. Over several months the endocrinologist reduced the carbimazole in steps, down to 5mg per day. In April 2023, following an antibody test, he told me I have no antibodies and this means that I don’t have an auto immune disease. I asked what is wrong with my thyroid and he said I probably have a nodular goitre.

I have been taking 5mg carbimazole since early 2023. I repeatedly declined radioactive iodine ablation. I caught a sinus infection in January 2024, for which in the last 14 months I have had 4 courses of antibiotics. Each time the antibiotics clear it, I have soon caught a cold (or once covid) and the infection has come back as bad as before. It is characterised by headaches, foul green sticky mucus and makes me feel dreadful. I won’t take any more antibiotics as they did not help.

Last Autumn in desperation, I paid £500 for Prof Tim Spector’s Zoe course. This was very good, although aimed at overweight and pre-diabetics, rather than me with a chronic infection. The outcome of the Zoe tests was that I have a very healthy gut biome and diet. I have also been working my way through Dr Michael Mosley’s ‘Just One Thing’ podcast series on BBC iPlayer. These are excellent. I can see that I have been seriously stressed for a long time and as a result had a bad sleep pattern. Incidentally added to the other stresses was a year thinking I had a life-threatening thyroid disease which as far as I know, now seems is not the case. Recently I have taken steps with my life and work to get rid of a good portion of the stress and continue to improve using Mindfulness and other strategies suggested by the 2 wellbeing doctors. My sleep pattern has improved enormously recently.

However, the sinus infection is persisting, plus for many months I have had continuous mouth ulcers. Also, in the last 3 months I have developed itchy skin. Itchy skin and mouth ulcers are known side effects of Carbimazole. It occurs to me that maybe this medication could also be contributing to the failure of the sinus infection to clear up spontaneously. Prof Spector says that he used to suffer from sinus infections and without antibiotics they only took a couple of days longer to clear up than when he took antibiotics. My conclusion is that, to have this infection for such a long time is not normal. Infection has never shown up in any of the blood tests. Otherwise, my health is excellent and I am building up my muscles again after a year of not being well enough to take much exercise.

3 weeks ago, I informed my GP that in order to see if it will help get rid of the infection I have cut down the carbimazole by half to 2.5 mg per day, with a view to eventually trying without it altogether. We agreed that I would have a blood test after 8 weeks to see if the reduction has any adverse affects . He said that he couldn’t agree to reducing the tablets without referring to the endocrinologist. I explained that I am not certain there is anything wrong with my thyroid. I only had the one abnormal blood test. Hyperthyroid as far as I know, is a symptom and not a diagnosis. I suggested a scan to confirm the presence of the alleged nodules. He said I don’t need a scan as nodules can be felt on examination. He then examined me and felt nothing. NB all my contact with the endocrinologist was on the phone so no one ever felt my thyroid; face to face was difficult after Covid. This increased my suspicion that the tiredness in early 2022 was caused by stress and maybe there never was anything wrong with my thyroid.

Since reducing the carbimazole dose the itching has gone altogether, as have the ulcers. The sinus infection is significantly improved. I get that this just might be the placebo effect, I am feeling a lot better and have higher energy levels than I can remember for the last few years.

My GP posted what I was going to do as a query on the endocrinology team forum. He said he had to do this as he risked being accused of medical negligence if he gainsaid the endocrinologist. I told him that I was not going to see this endocrinologist again as I didn’t like his attitude and I didn’t think he’d done an adequate job. He took a year to detect the lack of antibodies and did nothing to verify the presence of nodules.

Yesterday I received this in a text from the GP:-

"The endocrinology team have replied to my advice and guidance request regarding your carbimazole. They feel that your sinusitis problems are unrelated and do not recommend coming off carbimazole as you are apparently at high risk of relapse to an overactive thyroid if you stop. If you would like to discuss further please feel free to masker a routine follow up appointment."

I think I should ignore this and stick to my original plan with my GP ie a blood test in after 8 weeks of the reduced carbimazole dose. The text reads as if it straight from the mouth of my unloved endocrinologist.

If there were something wrong with my thyroid, surely, I should have a diagnosis. I don't think that I am at high risk of relapse. The only symptom I had was tiredness, so if I get a recurrence of this in the short term it’s a far less serious than the sinus infection that has blighted my life for the last 14 months. If I get any thyroid symptoms at least I will know if I have an issue with my thyroid or not. I am 73 years old and don’t feel inclined to do as I’m told. Can anyone advise me?

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Oona129
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SlowDragon profile image
SlowDragonAdministrator

The medics should not be only testing TSH

Have had any other tests?

Obviously you need an ultrasound scan - £100

thyroiduk.org/testing/other...

For full Thyroid evaluation you need TSH, FT4 and FT3 tested

Also both TPO and TG thyroid antibodies tested at least once to see if you have Hashimoto’s as this frequently starts with temporary hyper results before becoming hypo and can be mistaken for genuine hyper if not all antibodies tested

Very important to test vitamin D, folate, ferritin and B12 at least once year minimum

Low vitamin levels are extremely common when hypothyroid, especially with all thyroid disease

About 90% of primary hypothyroidism is autoimmune thyroid disease, usually diagnosed by high TPO and/or high TG thyroid antibodies

Autoimmune thyroid disease with goitre is Hashimoto’s

Autoimmune thyroid disease without goitre is Ord’s thyroiditis.

Both are autoimmune and generally called Hashimoto’s.

Significant minority of Hashimoto’s patients only have high TG antibodies (thyroglobulin)

NHS only tests TG antibodies if TPO are high

20% of autoimmune thyroid patients never have high thyroid antibodies and ultrasound scan of thyroid can get diagnosis

In U.K. medics hardly ever refer to autoimmune thyroid disease as Hashimoto’s (or Ord’s thyroiditis)

Essential to test vitamin D, folate, ferritin and B12

Lower vitamin levels more common as we get older

For good conversion of Ft4 (levothyroxine) to Ft3 (active hormone) we must maintain GOOD vitamin levels

What vitamin supplements are you taking

VERY important to test TSH, Ft4 and Ft3 together

Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins

Post all about what time of day to test

healthunlocked.com/thyroidu...

Testing options and includes money off codes for private testing

thyroiduk.org/testing/

Medichecks Thyroid plus BOTH TPO and TG antibodies and vitamins

medichecks.com/products/adv...

Blue Horizon Thyroid Premium Gold includes BOTH TPO and TG antibodies, cortisol and vitamins

bluehorizonbloodtests.co.uk...

Medichecks and BH also offer private blood draw at clinic near you, or private nurse to your own home…..for an extra fee

Only do private testing early Monday or Tuesday morning.

Tips on how to do DIY finger prick test

support.medichecks.com/hc/e...

Oona129 profile image
Oona129 in reply toSlowDragon

Sorry if I didn't make it clear. They tested everything they could on the blood tests including T3 and T4 at the same time as the TSH

SlowDragon profile image
SlowDragonAdministrator in reply toOona129

And what were TSH, Ft4 and Ft3 before treatment started and now

PurpleNails profile image
PurpleNailsAdministrator

If the source of hyper levels is from an over funtioning nodules, then it’s unlikely to resolve. Nodules tend to remain, to confirm a nodule you need a thyroid uptake scan. An ultrasound will detect nodules but only an uptake scan will tell you if you they are hyper functioning.

Which antibodies were tested?

You need, TPO, TG, TSI & Trab to rule out all thyroid autoimmune.

If you are having mouth ulcers whilst on carbimazole you need to have a full blood count to check your white blood cells.

I have history of sinus issues. I found antihistamines help control it.

What are your FT4 & FT3 levels? Your carbimazole dose needs to be adjusted by these levels not TSH.

Oona129 profile image
Oona129 in reply toPurpleNails

T3 and T4 were always within the normal range as far as I recall. The only abnomal result was the first TSH one. I was given the anti body test results verbally and as far as I know all relevant antibodies were tested

PurpleNails profile image
PurpleNailsAdministrator in reply toOona129

Do you have actual results?

Where in the range is quite important. If my FT4 (FT3) are 30% through range I start to get hypothyroid symptoms (I need to lower carbimazole dose). Once they reach 90% of range I start with hyper symptoms & I need an increase.

My Doctor has said “ they are in normal range” for both ends of the spectrum.

Oona129 profile image
Oona129 in reply toPurpleNails

I don't have any symptoms that I associate with my thyroid. The original tiredness went a while ago but has been replaced by tiredness associated with the sinus infection.

PurpleNails profile image
PurpleNailsAdministrator in reply toOona129

Then it’s a sign the carbimazole is adjusted to right level. Although I find it helpful to know my levels too.

Oona129 profile image
Oona129

Sorry I've got that wrong too. The last few tests were only TSH and not T3 or T4. Results 3.2 (March 2023); 3.1 (January 2024); 1.95 (August 2024); 2.65 (March 2025).

SlowDragon profile image
SlowDragonAdministrator in reply toOona129

All of these tests are totally inadequate.

Just TSH tells you nothing

Recommend you get FULL thyroid and vitamin testing organised

Oona129 profile image
Oona129 in reply toSlowDragon

In May 2022 Free T4 was outside the range at 28.2 and Free T3 10.1. But they were 12 and 4 respectively thereafter. They did test lots of other stuff in my blood. I think they will have covered all you suggest as necessary.

SlowDragon profile image
SlowDragonAdministrator in reply toOona129

You need to test at least annually

please add range on Ft4 and Ft3

But they were 12 and 4 respectively thereafter.

You wouldn’t want Ft4 or Ft3 below 50% though range

Carbimazole LOWERS Ft4 and Ft3

If Ft4 or especially Ft3 are low, then likely low vitamin levels

pennyannie profile image
pennyannie

Hello Oona and welcome to the forum :

There are 2 Auto Immune Diseases that could have caused your TSH to be low / suppressed - and these AI diseases tend to wax and wane throughout one's life - as there is no cure :

Graves Disease is treated with an Anti Thyroid drug as the T3 and T4 thyroid hormones can keep rising higher and higher put undue strain on your heart and considered life threatening if not medicated.

Hashimoto's is not medicated with an AT drug as the hyper phase transient and the T3 and T4 thyroid hormones fall back down into range by themselves and longer term ' swings ' into hyper continue until the immune system systematically destroys the thyroid with the patient then hypothyroid and needing the support of thyroid hormone replacement.

Carbimazole is an Anti Thyroid drug generally prescribed when there is a diagnosis of Graves Disease and positive over range TSH Thyroid Receptor or TSI / TRab - antibodies found circulating in your blood on the initial blood test results when your TSH was down at 0.01.

All the AT drug does is dampen down your immune system response and semi-block your own natural daily thyroid hormone production while we wait for your immune system to calm back down again.

The latest research is suggesting the longer the patient stays on the AT drug the better the long term outcome for the patient is :-

pubmed.ncbi.nlm.nih.gov/338...

Generally the NHS recommend a treatment plan with an AT drug for 15-18 months with there being regular follow up endocrinology appointments and dose adjustment of the AT drug to find and maintain your T3 and T4 thyroid hormone levels at around mid point in their ranges - leaving you as comfortable as possible and neither hyper or hypo symptoms.

Should remission not be found within this time frame the NHS suggest definitive treatment - RAI thyroid ablation or for those more seriously incapacitated and those already with eye issues a thyroidectomy -

Most recent research - ncbi.nlm.nih.gov/pubmed/306...

Obviously it reads as though none of this ever happened and your care package - not there -

though it could all have been a blessing in some ways as it reads as though you have sorted yourself out and whatever happened - just a blip !!

Do you have any blood tests, results and ranges, from when initially prescribed Carbimazole showing a TSH + Free T3 + Free T4 + the antibodies found positive and over range in these initial blood tests -

If you haven't you need to ask for a printed copy of exactly what you have been diagnosed with and the medical evidence of which antibodies were found positive in your initial blood test and your TSH + T3 + T4 results and ranges at diagnosis.

If no antibodies were found in your blood, maybe you had / have a nodule causing excess thyroid hormones - and maybe a scan could now rule this in or out ?

Oona129 profile image
Oona129 in reply topennyannie

Thank you Penny Annie

If it's possible it could have just been a blip and it could have sorted itself out then it makes sense to try without the carbimazole and see what happens. Maybe there was an auto immune thing going on that went again. I have a much healthier life and am I in a better place mentally now so I'm confident it's worth trying to get rid of the tablets. My ulcers and itching are better with cutting the dose by half and the sinus infection is improving at last. I really don't want to start with endocrinologists and tests again unless I'm ill.

pennyannie profile image
pennyannie in reply toOona129

Yes - I totally get it - but we really do need to know exactly what your blood tests were when all this happened and the antibodies found in your blood that gave rise to a prescription of an Anti Thyroid.

The AT drug blocks your own natural daily thyroid hormone production and low levels of T3 and T4 thyroid hormones - even in the range - cause hypothyroidism - symptoms of which maybe you tolerated as once you reduced the AT drug these issues started to decline.

Oona129 profile image
Oona129

initially the endocrinologist forgot to test for antibodies. Im on Carbimazole only because of the TSH, T3 and T4 tests from May 2022. There was a request for antibody testing then but this never got actioned until nearly a year later. This is the only time anti bodies have been tested

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