Carbimazole effects on levels - how long is elimination?

[L154C0]

My GP over-zealously prescribed 5mg carbimazole which I took for two weeks. The endo intervened and said no way should I be taking it so I stopped 19th Dec.

This week my bloods are:

TSH: 10.82 (0.3-5)

T4: 7.9 (7-20)

T3: 4.6 (3.5-5.8)

Question is: would 2 weeks of carbimazole still be having a lowering effect a month on, or is this the hashi hypo swing happening now d’you reckon?

Feeling wiped out, that’s for sure.

[helvella Administrator]

Carbimazole itself has a very short half-life and there should be effectively none remaining.

However, it is always more difficult to assess whether any of its effects could be contributing to where you are now. I rather think not but I'm no expert and could be wrong.

helvella - Splitting Carbimazole Doses

A short discussion about Carbimazole primarily focussed on splitting doses but containing other information which may be helpful to anyone taking, or considering, Carbimazole.

Last updated 06/01/2025

Link to blog:

helvella.blogspot.com/p/hel...

Sorry you have had to suffer from your GP's actions. "Over-zealously" seems somewhat polite.

pennyannie

[tattybogle]

i think the action of carbimazole is pretty short. ie hours / days , not weeks so thyroid should go back to producing as much T4/T3 as it can within ? a few days ? of stopping ( not 100% sure of my fact there, i;d have to look up it's half life )

So I don't think your fT4 / fT3 results are still affected by having taken the carbimazole.

but TSH can take a few wks to catch up with changed T4/T3 levels . so not long enough yet for that TSH result to be reliable.

i'd say you need to give it a full 6-8 wks at least before you'll know what is going on, but yes it could be the start of you going hypo now .

[tattybogle]

post says it was stopped on 19th dec, and not restarted.

[tattybogle]

oh good , you noticed already x

[pennyannie]

Hey there again ;

Seems I'm a bit late to your last few questions - sorry - I needed to go back a bit to catch up !!

I don't think the Carbimazole was at a high enough dose to have had that much significance -

it would have taken ' the edge off ' though not at a level to deal with people not knowing what they were doing - or factually alter your blood test result as dramatically as we see now.

So - I think this blood test tells us that you are dealing with Hashimoto's - and experienced a flare in symptoms due to an immune system attack causing a swing in your thyroid hormone production - and you were dealing with an over active thyroid -

you were positive for Hashimoto's AI Disease - and an ongoing mystery for Graves -

with Graves the thyroid hormones rise higher and higher - and it is considered life threatening if not medicated with an AT drug -

with Hashimoto's you experience erratic own thyroid hormone production when the immune system attacks the thyroid causing ' swings ' in symptoms and as we know a swing swings back - but with your thyroid damaged and less productive - and ultimately with your thyroid disabled leaving you needing thyroid hormone replacement.

You may find your thyroid picks up and levels off a bit - but you may well find you need to start taking thyroid hormone replacement in the not too distant future.

Looking back I see you are already with Sjogens - and guess have some understanding of AI health issues - which tend to hunt in packs - so best to get checked out for pernicious anemia, celiac and gluten as stomach and gut issues are common bedfellows with Hashimoto's .

No thyroid hormone replacement works well until the core strength vitamins and minerals - those of ferritin, folate, B12 and vitamin D are up and maintained at optimal levels -

so suggest you cash in on your doctors over zealous character - and get these blood test run.

Just being in a NHS range somewhere, anywhere, is not acceptable - as some ranges are too wide to be sensible - and we can advise - if you care to share any results and ranges.

As for Hashimoto's - I think I gave you this bedtime reading before - but here it is again - and the research and suggestions of Dr Izabella Wentz who writes as thyroidpharmacist.com

[L154C0 in reply to pennyannie]

thanks for this as ever reassuring advice

In between all this ‘swinging’ I’ve had FNA which shows thyroiditis so again, matching the Hashi destruction pattern. My symptoms have drastically changed from tachycardia to a resting rate of 58bpm and God-awful fatigue.

I’ve been putting off starting B vits because of blood tests keep needing to be done and the biotin skew if not stopped within a week.

But yeah, I’ll ask for a vitamin suite to be done next time - they owe me!!!!

Thanks ever so once again

[pennyannie in reply to L154C0]

Just looking back - you were found low in B12 around the time of the Sjogrens diagnosis - was this taken any further and you were tested for pernicious anemia then - before you started supplementing ?

Symptoms can tend to overlap - please ensure any eye drops, ointments or sprays you use to ease any eye discomfort are Preservative Free even those prescribed -

I'm hoping it is not a problem - but just be aware with any thyroid AI disease -

thyroid eye disease can occur - there are specialist units - usually attached to the large teaching hospitals where you will find an endocrinologist and an ophthalmologist working together to find your best treatment option - and the Thyroid Eye Disease Charity can signpost you to where your nearest specialist clinic is sited - tedct.org.uk

What medication have you been prescribed for Sjogrens - I remember registering with the British Sjogrens Association years ago - my lip biopsy came back negative and then realised my symptoms aligned more with the known damage and consequences of RAI thyroid ablation for Graves Disease - which I had some 10 years beforehand - though no NHS doctor would answer my thoughts and questions.

I think there has been a name change however as I can't find BSSA any longer but found -sjogrensuk.org/

[L154C0 in reply to pennyannie]

the drops I’ve been given are theoloz duo and theoloz gel for overnight. They really are good, although on a bad day I’m using them every 10 mins. Yes, BSSA has had a ‘rebrand’. I don’t want to take anything systemically if I can keep on top of symptoms topically (drops, mouthwash, B12 sublingual etc).