Hey,
I have an overactive thyroid, I was only diagnosed 3 weeks ago and they put me on carbimazole, I took it for a few days but I didn’t like the way it made me feel so I stopped. My doctor has advised to start taking it again so have took it again tonight and I’m very nervous.
Has anyone else had any experience with this medication?
How long will it take to work?
What are common side effects people have experienced?
Will it get better 😔
Carbimazole actually starts to work very quickly. If in sufficient dose, it arrests the production of thyroid hormone.
Once that has stopped, the issue is the amount of thyroid hormone already in your body. While you have lots, you will continue to have the symptoms of hyperthyroidism.
In time, which could be some weeks, the amount of thyroid hormone drops. That is the most difficult point. If you don't either cut the dose, or add levothyroxine, you would become hypothyroid.
It is usually recommended that you split your carbimazole dose - at least when you are starting out. This is because it doesn't last very long in your body and it is possible for your thyroid to start producing thyroid hormone again if you leave it 24 hours between doses.
You must read the Patient Information Leaflet slowly and carefully and more than once. There are issues, such as having a sore throat, which could indicate a very serious effect of carbimazole in a small number of cases. When it says to seek advice - do so straight away.
Others are better placed than me to let you know about their experiences.
Yes, that's interesting. I was looking up Methimazole(sp) , the veterinarian equivalent of Carbimazole, the other day because my cat has to have it (she has hyperthyroidism). I was surprised to see the half lives were 6.5 and 5.5 hours respectively. it's hard to know exactly when to take her for a blood test, before or after medication or right in the middle of a dose. The problem is made moot by the fact that she doesn't like me to rub it in her ear so runs a mile when she as much as sees me. Even for food she hides outside until the bowl is put down and I am well out of the kitchen. I conclude that dosing for hyper is more complicated than for hypo.
Carbimazole converts into Methimazole very quickly. I have no idea why the UK uses Carbimazole and the USA uses Methimazole (seems to be for humans as well as animals).
Are those half-lives specifically for cats? I suspect they could vary by species.
Timing of blood tests might not actually be very important - but I'd want to do a whole lot of reading to see what actually happens.
(Do cats have 18 half-lives?)
In humans, Carbimazole has a half life of 5.3-5.5 hours. Large daily doses (eg 40mg/day) are typically split, but my endo said that it was more important to take the full daily dose than to split it - so if people keep forgetting the evening dose, they may be told to take the whole lot at once from the outset. The half life of PTU is much less - less than two hours - so this really does need to be split into three doses throughout the day.
Half lives quoted were for humans (as Valarian said). I didn't know that Carbimazole converts Methimazole (Meth). Perhaps there is a species factor, maybe the conversion is not efficient in cats and they are therefore put directly on Meth, I will ask my cat's vet, he knows a lot more about thyroid matters than my doctor. 18 half lives, good one.
Clin Endocrinol (Oxf). 1979 Jun;10(6):637-48.
Rapid conversion of carbimazole to methimazole in serum; evidence for an enzymatic mechanism.
Nakashima T, Taurog A.
Abstract
Carbimazole (CBZ) is one of the major drugs currently used for the treatment of Graves' disease. It is a carbethoxy derivative of methimazole (MMI), originally developed in the hope of obtaining a longer acting drug than methimazole. In the present study we have demonstrated that carbimazole is rapidly converted to methimazole in vitro by serum from rats and humans, and we have obtained evidence that this conversion is enzymatic. Experiments with [35S] CBZ in rats showed that the drug is so rapidly transformed to MMI after i.v. injection (within 3 min) that very little of the unchanged drug would be expected to reach the thyroid gland. The antithyroid action of CBZ in rats, therefore, can be ascribed entirely to the MMI to which it is rapidly converted. Although no experiments were performed with human subjects in vivo, the very rapid conversion of CBZ to MMI by human serum in vitro suggests that the antithyroid action of CBZ in humans can also be attributed to MMI. The original expectation of a longer acting drug has, therefore, not been met by CBZ. On the basis of the studies reported here there appears to be no advantage in using CBZ in preference to MMI for the treatment of Graves' disease. Although the in vivo action of CBZ must be attributed to its rapid conversion to MMI, the drug does possess inherent antithyroid activity. This was shown in the present study by the finding that CBZ is as potent as MMI in blocking thyroid peroxidase-catalysed iodination of thyroglobulin.
PMID: 476986
So a hyper cat is every bit as intolerant and impatient as a hyper human !
In humans, it would be more important that she took the full dose (with carbi, not the alternative PTU), than whether it had been spread across the day. I’ve never been told that blood tests need to be taken at a particular point in the medication/ food cycle, although typically they have been early morning because that what my GP is geared up for. With hypos, it seems optimum test timing is driven by the fact that TSH tends to rise naturally throughout the day. With hypers, TSH tends to stay rock bottom anyway until the thyroid levels come back into range (and even for a few months after this) .
Cats often being quite contrary creatures, this may not apply to them !
I was diagnosed with hyperthyroidism 20 years ago and offered carbimoizole I decided to go down he food route - my heart rate was 100 at rest! Not suggesting you should try this just thought some of the info might be useful alongside your meds I ate all the foods that slow the thyroid down wheat, soya, dark green leafy veg and low salt. In 4 months my heart rate was 60 again. I had added too much iodized salt to my diet which caused my hyperthyroidism this was at the hospitals advice to try to cure my cfis which thankfully sorted itself out. my experience has shown what we eat can affect us.
Hi The cause of Thyroid disorders is an auto immune problem. Realising I have had all the symptoms of an over active thyroid for sometime I have just been watching this series on youtube that might be of interest to you. Treating the underlying issues that are causing the autoimmune response using a holistic natural approach through diet, supplements, environment, lifestyle etc will correct thyroid problem without the use of medication, if you decide that's not the approach you want to take. I personally prefer the approach of finding and treating the cause, allowing health to be restored rather than having to depend on medication and deal also with side effects.
Betrayed Episode 8
youtube.com/watch?v=EM9qWc_...
All the other Episodes should be available on Youtube that will give you more insight into the causes of auto immune disorders and how to correct them.
Good Health
Did you self treat successfully?
Hi!
I am on Carbi - now on a very low dose of 1.25mgs. I would only say to be very cauktious about not taking the medication if you have been diagnosed with an overactive thyroid as there may be serious consequences as everything speeds up!
I would suggest reading/looking at websites....Elaine Moore, Amy Myers, naturalendocrinesolutions.
You can most definitely introduce a supporting complementary routine whilst on Carbi and that will almost certainly help to bring the thyroid back under control again.
Helping to minimise stress, going gluten-free, looking at diety - will all help.
Have you had your antibodies checked?
As has been suggested - split the dose of medication.
All the best.
xCarole
Could you post your bloods just so we can double check your diagnoses? and describe you symptoms. There is such a thing as splurious TSH results that most doctors wont be aware of. Also take your pulse and temperature. I am just questioning why you are feeling worse on meds most peple find helpful.
When I was first diagnosed with Graves I was prescribed 20mcg a day for four weeks and told to come back for another blood test. After the four week blood test my endocrinologist whom I hadn’t seen at this point whole to me telling me to get more carbimazole from my GP and double the dose which I did for another two months before I finally got to the hospital to meet an endocrinologist.
I wouldn’t say I had any particular symptoms over and above the horrendous hyper symptoms I already had when I was taking carbimazole, I got a sore throat a couple of times, first time I was straight down to my surgery and had a blood test right away, second time the GP I saw suggested a ‘wait and see’ approach and I was happy with that. I felt I would have felt much more ill had it been agranulocytosis.
My hospital treats with block and replace which is where they stop your thyroid producing thyroid hormone altogether then replace it with levothyroxine and I would say I didn’t start to feel really good until I started taking levo as well. My hyper symptoms gradually stopped but it wasn’t until I was taking the levo as well that I felt good.
I was a bit shocked by some of things I read about carbimazole but it wasn’t a problem for me at all and I’ve read somewhere that if you are going to have problems taking it, you will have them right away.i used to feel that endocrinologists didn’t want patients to be using it in the long term because they have to keep you on their books whereas if it doesn’t work then they like to either give you radioactive iodine or a total thyroidectomy (TT) and kill off your thyroid altogether which I definitely didn’t want. So my personal opinion, (I’ve not got any proof!) is that I don’t think endocrinologists want you to remain on carbimazole in the long term because they can’t discharge you and I’m not sure their reasons are always in the patient’s best interest.
I suppose it depends on how ill you are feeling and how long you have been hyper as to whether you are prepared or even able to use a holistic approach. I imagine healing yourself holistically might take a while so I was quite happy when at long last a doctor finally realised that I was really ill and gave me something that could make me better - I had been given the run around previously, even being told by one that I needed a holiday!
I took 40mcg for a year, three months on its own then nine months along whith ever increasing amounts of levothyroxine then after a hospital visit a year after I was first diagnosed I stopped the lot and I’ve been in remission ever since. Some people are treated with ever decreasing amounts of carbimazole and I’m sure s9me9ne will come along and tell you how that works.
I always took my carbimazole first thing in the morning and I never ever split the dose -I’m not sure why though. My hospital doctors knew I took it all at once and never commented.
For what it’s worth, I’d do what your doctor advises and get going on the carbimazole. My pharmacist said to take it with a high dose vitamin C so I always took 1000mcg vitamin C plus zinc. I cleaned up my diet too so yes you can do holistic but I suspect it’s the carbimazole that fixes you fastest.
I went totally gluten free - which has massively reduced my thyroid antibodies - concentrated on improving my diet by eating lots of fish, eggs, chicken, nuts and seeds etc and cut out all junk food and fizzy drinks. I drink water, decaf drinks with the odd glass of red wine or prosecco thrown in but no more junk food. That plus relaxation and gentle exercise.
Hi Shanini
First of all, without intending to diminish your concern, just be aware that anxiety and jitteriness are often symptoms of a hyperactive thyroid. Most of us had no idea how important the thyroid was to so many of our bodies’ systems until it started to misbehave !
I’ve been taking Carbimazole for over twelve months now. Common side effects include a feeling of nausea, and hives/rash. If you can live with them, these symptoms can disappear after a couple of months, and the rash may respond to over the counter antihistamines.
If you feel really unwell, and have a sore throat or mouth ulcers with a feeling that you have an infection, you should ask your GP or even A&E for an immediate blood test, explaining your symptoms and that you are on Carbimazole This is because there is a rare but potentially dangerous side effect which can your white cell count and reduce your ability to deal with infection.
If you can’t tolerate Carbimazole, there is an alternative called PTU. This is more likely to cause liver problems than Carbimazole, so is not usually the first choice.
A hyperactive thyroid needs to be treated, and if you can’t /won’t take the medication, the only real alternative is to have your thyroid removed, either by surgery or with a dose of radioactive iodine. Most of us prefer to live with some of the side-effects of anti-thyroid treatment rather than lose our thyroids.
As others have said, we may be able to give you more info if you post your test results and associated ranges (typically in brackets after the result). The tests you need are TSH, FT4, FT3, and antibody tests - TPO, and either TRab or TSI . You will probably need to wait until you have an appointment with an endo (have you been referred yet?) for the last three.
You can find more info on Carbimazole here patient.info/medicine/carbi...
Hello, I have just posted my result for the first three. I have seen an endocrinologist but not had the last three blood tests.
I’m have a scan on my thyroid next month.
FT4 24.6
FT3 11.3
TSH 0.01
Do you have the ranges ? (Probably in brackets after the result).
It’s difficult to be sure without seeing the ranges, but with those commonly used in the U.K., your FT3 would definitely be elevated, while your FT4 would probably only be slightly above range. The FT3 is probably sufficiently elevated for you to have been feeling symptoms , and it may take 4-8 weeks for you to begin to feel better, although when this happens, it can make quite a dramatic difference. In the meantime, if you’re suffering from palpitations and tremor (horrid), or jitteriness, your GP/endo may be able to prescribe some beta blockers to help with this.
Are you in the U.K. ? A thyroid scan isn’t always done in the U.K., so maybe your thyroid is very swollen, or has nodules (often harmless) that they want to take a look at before looking at the antibodies. The most common cause of being hyperthyroid in the U.K. is an autoimmune disease called Graves’(named after the doctor who first described it), but you really need antibody tests to confirm this.
FT4(24.6 pmol/L)?
FT4 (11.3 pmol/L)
TSH 0.01 mu/L
That’s all I was sent.
I am in the UK, my endocrinologist suspects my hyperthyroidism is either caused by toxic nodules or past lithium use?
I do have a tremor and a bit jittery, I don’t know how I feel about beta blockers though.
Thank you
Maybe talk to your GP about symptoms, and see what they suggest.
Toxic nodules are usually benign, so try not to get too anxious about this. (Telling a hyper person not to get anxious can be a bit like telling ice cream not to melt, but stress really does make us feel worse). They may continue to treat with Carbimazole, or you may need surgery or radioactive iodine treatment .
Lithium is more commonly associated with hypOthyroidism - in fact, it used to be prescribed to treat hypERthyroidism. However, it seems it can sometimes lead to an autoimmune hyper response, so effectively Graves’, which will be treated in the first instance with Carbimazole . Most of the hypers here (including myself) have Graves’, so you’re in good company !
Ranges look something like this: FT4 24.6 (12-22) and so on. If the levels were all you were given you need to ask for the lab ranges as they are important. You might actually be having a hashi flare and not be truly hyper at all (to know that you need TSI and TRab antibodies - if positive it is Graves - and TPO and TG antibodies - positive is Hashimotos.
Looks as though they are investigating nodules to begin with
I was just relieved to get rid of all the terrible symptoms I had due to being hyperthyrpid I felt so bad.
Hi I was diagnosed accidentally as hyper last Feb. I went to the GP for severe aches and pain in my muscles. Bakers cyst was extremely painful. I also had recurrent voice loss over the winter period and just put it down to work related. I requested a blood test as I felt something was not quite right as I'd never experienced such pain. Anyway blood test revealed hyperthyroidism, and low vitamin D and I was put on 20mg Carbimazole and high dose Vitamin D tablets. I had horrible side effects from it within less than a week. I had scaling skin, tremors, feeling faint and just so unwell. The dose was reduced to 5mg and later to 10mg. 6 month's on I'm now on 5mg, but unfortunately I have now gained 1 stone and really not happy with gaining weight.
still in shock and very nervous
Am I having a nervous breakdown?
Excited and nervous 😊
GP appointment Monday -- am nervous. :(
nervous system role in thyroid stimulation 
