Worried about starting on Carbimazole

Posted , 6 users are following.

Hi everyone, just after a little advice from those that are already taking Carbimazole.

Recent tests I had showed that my thyroid levels were high (almost 30 is what doc said). I am waiting to see the endocrine specialist on 14th July but in the mean time my doc wants to start me on Carbimazole 5mg tablets. I have asked to have another blood test done before starting the meds as I am very nervous about starting medication.

Also, I went hyperthyroid 7 years ago and after about 3/4 months it settled by itself.

My doctor just warned me that Carbimazole effects your immune system and can make you more susceptible to ill health. I'm thinking this must be bad because GP's hardly ever warn you of side effects in my experience, they always say there aren't any to worry about! But I am very worried about this. I'm a single parent to 3 kids, have a lot of stress and can't afford to be ill all the time. The hyperthyroidism doesn't make me feel ill apart from palpitations but that has stopped happening. Also, I'm afraid that I won't be able to control weight gain if this medication effects my metabolism.

Any advice would be much appreciated. I need to stop the anxiety! Thanks.

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7 Replies

  • Posted

    Hi, I have been on and off Carnoimazole for about 8 years now and it has never made me sick or have any side effects. He maybe means if your white bloods cell get low you can get a sore throat, mouth ulsers or generally feel unwell. Would be interested to hear other people comments. I have been on Carboimazole for 3.5 month's now and feel fine. Good luck x
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  • Posted

    Hi Bird82. I started taking Carbimazole in March. My GP  warned me that a minor group of people do not tolerate Carbimazole well and might have problems with their immune system.

    I can empathise with you since I had the same worries when I started taking Carbimazole. My GP also instructed me to go for an immediate blood test should I get any sudden mouth ulcers, sore throat, or other infections. 

    Once you are on Carbimazole your will have to go for blood tests every few weeks and they will detect any changes to your immune system or thyroid levels. 

    I got started on 30mg Carbimazole. Gradually my dose was dropped to 10mg. Already after 2 weeks on this medication I was feeling much, much better. 

    To put your mind at ease consider that your GP suggested starting you at a low dose of Carbimazole, your blood levels will be monitored regularly, and  you can allert your doctor if you get a sudden sore throat. 

    It must be really difficult with 3 kids to care for but this is the advise every doctor gave me: Take is easy! I hope you will feel better soon. 

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  • Posted


    I had to take 30 mg of Carbimazole when my thyroid went hyperactive two years ago. Within two weeks I felt much better and after a month had blood tests and the dose was reduced to 20mg and within 6 months I was taking 5mg only which I did for a year. I am now off the carbimazole completely and am hoping my thyroid can cope on its own.

    My GP also warned of the sore throat and ulcers and to get an immediate blood test if necessary. there is another drug you can take if carbimazole doesn't suit. I didn't have any nasty side effects. Long term use can effect your short term memory I understand, but my GP says that is 2/3 years plus if on continuous high doseage.


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  • Posted

    Thanks to everybody for responding to me. My GP has prescribed me 5mg to take twice a day so I'm guessing that's quite a low dose then?

    Did anybody experience weight gain with Carbimazole??

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  • Posted

    Hello Bird82,  I've been on carbimazole (or Neomercazole in my case) twice since 2008, each time for 18 months, taking 20mg twice a day.  I too was warned that if I had a sore throat for more than 2-3 days, to go immediately to A&E.  But I never needed to and seemed to tolerate it very well.  Yes, I did put on some weight, but only 3 kg. 
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  • Posted

    Hi I was only diagnosed 3 weeks ago and put on Carbimazole

    60 mg a day so very high as all previous comments it is about

    If you have sore throat \ fever. I am not having any side effects and feel so much better. With weight I had lost 1 stone 4 pounds in 4 weeks before I found out about my thyroid and to date not

    Lost or gained. Good luck.

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  • Posted

    They are now finding that lower doses work as well or better than high doses and patients are more able to tolerate the lower doses.  I have had no problems with liver or blood count and have been monitored closely for this.  However, I have stuck to the lower doses and added supplements to help them work.  I took Reglar L-Carnitine 3,000 mg, vitamin D 1,000 mg, anti-inflammatories like Omega 3 and curcumin and Milk Thistle for liver.  The all helped my course and my meds along.
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