Methimazole side effects/Endo says thyroid removal...

Posted , 6 users are following.


I had hyperthyroid 20 years ago, and now having it again. 

My FREE T3 20.8 pg/mL (normal range is 2.0 - 4.4 pg/mL)

My Free T4  >7.77 ng/dL(normal range 0.82 - 1.77 ng/dL)

My TSH <0.006 uIU/mL

So i started Methimazole.  it wast working, my symptoms actually got worse the first couple days on it.  So I increased my dosage to 60mg-80mg a day.

My symptoms got controlled, and my free T4 is now 1.6 (normal range 0.82 - 1.77), my TSH did NOT change.

However, after about 3 weeks on methimazole, I am having serious side effects.  It started with severe hives.  My hives would occur all over my body. Antihistamine does not help.

Now I am having really bad joint pains.  i feel my fingers swallow, pain. my right shoulder is in severe pain.  I can NOT move my right arm at all.

i have decreased my methimizole dosage to about 40mg, i feel slight dizziness, which i think 40mg of methimazole is a bit too low for me. I still have hives, although not as severe.  But my joints are still in serious pain, and i cannot move my right arm.

I emailed my endo about my side effects, and she wants me to stop methimazole completely, and recommended me to talk to my ENT doctor about thyroid removal (I have couple nodules in my thyroid, which i will have biopsy later on this week).

Has anyone faced similar experience? should i push my endo to change my medication to PTU? my endo says in her email that i am most likely would have the same side effects of PTU.

I really do not want to remove my thyroid and be on medication for the rest of my life!

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  • Posted


    Firstly   Don’t let anyone destroy your Thyroid Gland  ... Unless you are fully aware of the consequences of doing that !

    If you take out your Thyroid Gland ... you WILL become  HYPOthyroid and that may be worse for you ...  they say that Graves’ disease cannot be cured but you certainly CAN control it to become Euthyroid .. which certainly FEELS like a cure !


    You’re dose of 60-80mg of Methimazole  seems absolutely excessive to me .

    I may be wrong ... and others will also advise ... but no wonder you’re in such pain .

    Usual high dose would be more like 20mg to start ... going slowly down to 5mg or even 2.5mg to become Euthyroid 

    I woukd think your Endo should know THAT 

    My advice would be to go quickly to your doctor and have another set of bloods done to find out exactly what is happening  ask for your Antibodies  to be tested again too ..

    Tell him you need to have 

    B12 tested

    Also D 

    And Magnesium 




    Arrange for that to be done quickly and come back on  with the numbers .. ( and those in brackets )  for further advice 

    Linda187 hopefully will read your post and  come to help you 

    You should rest as much as possible in prone position .. warm baths , fresh food and plenty of water to drink

    Please keep us posted 


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  • Posted

    Wendydon, I have never seen ANYONE post to this Board that they are taking 60 to 80 mg of Methimazole.  Surely your doc did not tell you to do that?  If so, fire him or her.  If not, don't ever self dose Methimazole.  Let the docs determine your dosage.  At that dose, you are in danger of liver damage or blood count abnormalities.  You should ask your doc to do liver testing and CBC tests.  These have always been done on me every time I see my Endo and I have never taken a higher dose than 10 mg.  The allergic reaction you described is called "serum sickness" and this is serious.  I have had it twice, once due to a bee sting and once due to an antibiotic I was taking.  When I had it, I needed to take decreasing dosages of Prednisone for a week to treat the problem.  I know others who have had it and did not get treatment and they later went on to have other autoimmune diseases.

    You can get your labs down with lower doses of Methimazole plus supplements.  I found for me that it was best  to get tested for my levels of vitamins, minerals and amino acids before I started taking supplements.  If you have a cooperative doc, ask to be tested for Total Carnitine and Free carnitine levels, vitamin D, and Magnesium to start in addition to the ones Madge mentioned.  If you add these to your lower Methimazole dosage, you will feel better and more likely recover better.  The carnitines are especially helpful in raising your TSH.  I think this is worth giving it a try before you make a decision to remove your thyroid.  It has worked for several of us on this Board.  Also once you are euthyroid, that is all your levels are within normal, do not discontinue your meds unless your antibodies have also normalized.

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  • Posted

    Thank you madge and linda for the replies..

    my doctor first gave me daily dosage of 20mg, But for the first few days, my symptom actually deteriorated. I increased dosage myself.  However, when i saw my endo doc for the second time, i mentioned i was taking 60mg-80mg.. and she didn't make any fuss and changed my dosage to 60mg..  

    I wish i was told or researched myself to realize that Antithyroid drugs takes a few weeks to work.. 

    I went to ER today because my hive was so severe and i couldn't move my arm.  My lab tests were normal, liver and blood cell counts are still normal (knock on wood).  I am told to stop the methimazole and propanolol (beta blocker) for now, and go on a fixed dosage of Prednisone steriod, 40mg daily for 5 days, and see if it heals

    I also have couple nodules in my thyroid, and i am seeing an ENT doctor.  she suggested me to take a biopsy of the nodules and i am doing it tomorrow

    I am seeing my general doctor on friday, i will ask for the antibody and vitamin level blood tests.

    I am seeing my endo doctor on this coming monday, and i will see what she says (i may need a new endo doctor)


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  • Posted

    I hope you're better. I recently about 2 months ago was diagnosed with hyperthyroidism. Initial dosage was 5mg of methimazole, two weeks later 5mg twice daily. Ok, no problem. Then updated to 10mg twice daily. Now 3 weeks in the hives oh so itchy. My thyroid issue was caused by iodine poisoning, due to prolonged use of amiodarone. Now I seem to have adverse reaction to most medications.

    Itchy, tearing up my skin...

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    • Posted

      It is not unusual to have a hives reaction to the antithyroid medication.  Many on this Board have had it.  However, because I have had this kind of reaction to other things like bee stings and antibiotics, I always either go to Emerg or ask my doc for Prednisone.  The reaction I had was called serum sickness and many medical staff do not know about it even in Emerg.  If you mention it to your provider, they will probably look it up if they don't know.  I was very fortunate that when I had the reaction to the bee sting that went on for a month, someone referred me to an expert in bee stings and he told me what it was.  I had just been to Emerg before I saw him and they didn't have a clue but when they knew I was going to see him, they happily encouraged me to do so.  In my case, I never had a higher dose than 10 mg but I was getting hive-like welts across my forehead which I was able to get to stop by wiping my forehead with a cotton pad soaked in Betamethasone scalp lotion.  I had remained on the dose of 10 mg of Methimazole for 2 years with a 0 TSH for that period until I did further research and found out about supplements that really help which I added to my Methinazole.  I was then able to get my TSH to rise and my doc then lowered my dosage of Methimazole.

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