block and replace therapy, or reduction of medi... - Thyroid UK

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block and replace therapy, or reduction of medication?



I don't like taking any drugs and have recently been diagnosed with hyperthyroidism. After a month of trying a lot of complimentary therapy, my blood results had simply soared.

I am now on carbrimazole, 40 mg per day.

The aim is to block and replace but I'd rather see the results come down (T4 now 26 - was nearly 70) and when it's normal just reduce medication. Why isn't this done? Has anyone tried? Be very grateful for advice... thanks

41 Replies

It is done. But it can be difficult to get a dose of carbimazole that just suppresses the production of thyroid hormone enough, but not too much,so that you are OK.

The rationale seems to be: Block completely (so the thyroid is out of the equation. Then give an adequate dose of levothyroxine which can be adjusted reasonably well (at least to the nearest 25 mcg - or, with alternating doses, to 12.5 mcg a day).

Not everyone is treated with block and replace. And there might be other reasons/arguments for taking one tack rather than another.


PS 26 reads better than 70 even without a reference range!!! :-)

tilly83 in reply to helvella

Thanks I instinctively feel that monitoring is potentially better but more of a hassle for medical staff in terms of checks and be honest at the moment I just feel annoyed at having to take anything....

I had block and replace therapy its very common for hyper conditions because its easier to control your levels that way as hyper can be dangerous I would just go with it, it will work well for your symptoms and will remove the anxiety about being treated which is also common with hyper conditions :-)

Thanks, what's happened to you now...I have nodules on thyroid and think these are particularly hard to treat....


This is an excerpt and if you would like the whole Pulse article (it covers all thyroid problems) email and ask for a copy.

The three treatments for hyperthyroidism of Graves’ disease – antithyroid drugs, iodine-131 and surgery – are effective but none is perfect.4

Iodine-131 will almost certainly cause hypothyroidism, usually within the first year of treatment, as will surgery, given the move towards total rather than subtotal thyroidectomy.

There is no consensus among endocrinologists about the correct dose of thyroid hormone replacement so patients may prefer to opt for long-term treatment with carbimazole. Standard practice is that carbimazole is given for 18 months in those destined to have just one episode of hyperthyroidism lasting a few months.

But there’s no reason why carbimazole shouldn’t be used for many years in those who do relapse. Any adverse effects such as urticarial rash or agranulocytosis will have occurred within a few weeks of starting the first course.

Thanks, that's more along the lines of what may feel better for me, to stay on carbimazole but on an amount that just takes care of things....

I have Graves and have been on carbimazole since May. I also had sky high T4/T3 I did go underactive for a while bit my last TSH was .68, so I think for some people it does work - it has for me. My endo has been very good and has monitored me closely having bloodtests every 6 weeks.

sorry forgot to say I'm now only on 5mg per day.

tilly83 in reply to Tory

Thanks for this, that's what I'd like to go for. I still haven't had a diagnosis, it started in 2010 with lump on neck and losing weight, I could eat my own body weight in chocolate (every other woman hated me!) and still lose weight. It's going back on a bit now. I am going to ask for bloods to be done very regularly x

i was diagnosed hyper in feb 2012 and immediately put on beta blockers and carbimazol, like you i don t even like taking headache tabs

eventually i stopped the beta blockers and over time the carbimazol was reduced however a blood test then revealed my white cell count had dropped dangerously low and i was taken off carbimazol and put on ppt and had liver scan to check ok as also high alkalysing phosphate levels

all ok now on ppt 1 tablet daily

tried to reduce to 1/2 daily but itching and dry skin patches on face occur so back on 1 per day

seeing my endo next week his view is we ll stop all meds and see what happens as we can do radioactive pill which i m against

i ll ask if i return to low dose of carbimazol whether this will cause the same thing again as reluctant for any op or radioactive

think long term carbimazol is better

after reading all the blogs on here it seems hyper is easier than hypo

hope you start to feel better soon


tilly83 in reply to hotfeet

Thanks so much for this, it's really helpful, sounds very scary about blood count and liver, I hate taking anything, am going to see what next blood results are like and then just reduce as I think doctors want to block and replace because that's easier for them to control, glad you are feeling better..x

strangely i had no symptoms of low white cell count or any idea about alkalysing phosphate levels

once symptoms were under control i felt absolutely normal again which has been great

blood test today and endo appt next week

have just started to get back ache which i did nt get before so will ask about that at endo appt

take vit d and calcium supplements and omega 3 and multi vit

hope you feel better soon


tilly83 in reply to hotfeet

Thanks, am going to ask at next blood text to test for white blood cells, that sounds scary...I too take lots of vits, this is such a relief to find this site, nobody else really understands and I don;t want to bore them so don't talk about it...x

Silver_Fairy in reply to tilly83

I have Graves and have been on block and replace. After the 18 month course I was told to stop all medication to see if I had gone in to remission. I started having returning symptoms of Graves after about a month. The Endo tried pushing RAI or surgery but was reminded I have TED so cannot have RAI and heart failure so would rather not have surgery.

I persuaded her to let me try Carbimazole alone. I started on 40mg (I think they prefer titrating down because of the dangers to the heart with Graves) and with 8/10 week blood tests I am now down to 5mg. I still feel hypo but not so horrendously so!

Not sure whether I will try 2.5mg after the next blood test or try stopping to see how I go. My previous plans were to stop and to then go onto natural therapies.

Even if I stay as I am, I am a 100% better than I was on block and replace which took me to a dark, scary place. (It does work for some though!)

Some websites say that there is a danger to the liver with long term Carbimazole treatment but others say not, who to believe?! Also it affects some peoples white cell count.

hotfeet in reply to Silver_Fairy

i too have hyperactive thyroid endo thinks graves dr does nt as no antibodies in blood?

i ve been treated by my dr solely til the alkalysing phosphate levels became high then i ve just seen the endo once due again next week

you mention heart failure was this as a result of thyroid?

i like you have looked at effects of long term carbimazol or ppt and think carbimazol is the preferred choice

tx hot feet

Silver_Fairy in reply to hotfeet

Sorry if I scared you, no I already had heart failure but strangely enough the medication (Amiodarone) I was on for my heart complaint caused me to have Graves :\

hotfeet in reply to Silver_Fairy

sounds about right! you re given a med to sort one thing out and it brings on something else!

unfortunately it s not something you have much choice about

tx hotfeet

tilly83 in reply to Silver_Fairy

Thank you, this is really useful to hear about, I'd much rather reduce and see how that goes.... I have also completely changed my diet - no more wheat, have acupuncture and do yoga, try to cut down stress or handle it better...x

Hi I would just like to add something.

I have Graves and am hyper and have been taking carbimazole first at high dose and then at a low dose since May 2011.

Many people on here are hypo not hyper and have no understanding of the difficulties faced by hypers. Hence people look on here and see hypo comments but not many hyper comments and assume it is because being hyper is a doddle.

In actual fact being hypo you are usually treated by a GP and being hyper you must be seen by an endo. With hyper there is a risk of many serious complications if untreated such as a thyroid storm or heart problems. The only good outcomes for the majority of hypers is to have RAI and or surgery and become hypo. Not many people statistically recover by using meds alone.

Plus many people who are diagnosed with being hyper do not know/are not told the problems and think that taking meds are optional. It is a serious condition and must be taken seriously. It is not easier being hyper than hypo - far from it.

hotfeet in reply to greenginger

are you therefore considering rai or surgery? have you been fine on carbimazol?

i m back to see endo next week was diagnosed with overactive thyroid last feb and was seen solely by my dr til alkalysing phosphate levels raised

my endo immediately said i had graves although dr said not as no antibodies in my bloods

i think mine was triggered by a virus and as im now 49 i assume with menopause looming that hormone levels inc thyroid will go mad again shortly so am reluctant to do rai or surgery? i said i thought being hyper was easier as my symptoms before being medicated were nt as severe as those posted on here for hypo

the worst i ve felt is breathless and weak legged all stopped now fortunately

i ve never felt exhausted or depressed if anything most of the time absolutely fine

tx hotfeet

tilly83 in reply to hotfeet

Thanks for this you sound a bit like me, I am fine on carbimazole at present not feeling any side effects and not depressed (well apart from weather!), mine was triggered by extreme sore throat in 2010 which caused lump and months of sore throats, no symptoms (came after a son was nearly killed in Afghanistan so no wonder), then no stress but lost weight and bloods revealed T4 of 47 (should be 12 to 22) tried complimentary but sadly may as well have torn money up in shower as shot up to nearly 70. Glad I tried though, have changed diet - no wheat, 95 per cent veg, do yoga and try to keep calm (and carry on!) these answers make me feel I want to reduce not block and replace and see how it goes. Also I'd like a scan but not forthcoming yet as feel that will tell me what state nodules are in. Thank you x

Heloise in reply to tilly83

tilly, I was going to ask you what caused this when I read your first question and now I see what stress you have been under. My son was in Iraq for 15 months, I know the toll it takes. Given time, it is possible to restore the thyroid. With the support of a beta blocker and either carbimazole or PTU which I read was save to take indefinitely.


Selenium might be a good addition and if you dislike another pill, a few raw brazil nuts every day may help. Also if you are into brainwave relaxation there are are cd's or tapes that can be effective if you use earphones with them. This is just a sample:

tilly83 in reply to Heloise

Thanks Heloise, I'm at work now but will listen later... and I do rattle with supplements, selenium included! x

Heloise in reply to tilly83

Tilly, there is some science behind this if you have heard of biofeedback. It affects the hypothalamus in a good way. Brainwave technology is just one method.

tilly83 in reply to greenginger

I know but I don't want to be hypo either, I just wish I'd take stress and the effects of it far more seriously rather than just getting on and ignoring it, still it's a lesson I'm dealing with now hopefully not too late! x

BillieSt in reply to greenginger

I totally endorse your post. I'm on alternate days 5mg carbimazole which seemed to have me stabilised but unforch, my last set of blood tests showed I've 'crept up' again. Consultant was wary of suggesting RAI until he can be sure not to give me too much and avoid going too hypo. I had a recent discussion with GP who gets copies of consultant's letters he sends to me, she said I shouldn't worry too much about going in the opposite direction because that would mean I could be treated at the surgery as opposed to seeing an endocrinologist and it would just be a matter of 'topping up' my thyroid as opposed to the complicated scenario of being hyper. The one good thing is being able to eat well and not put on an ounce but it doesn't outweight the other symptoms.

tilly83 in reply to BillieSt

I know it was driving my friends mad that I could eat my own body weight in bagettes and chocolate and still stay slim, I am putting it back on now and will have to be more careful but it was horrible running to the loo all the time (and embarrassing) and I am not getting nearly the same amount or duration of palpitations.... you are right it is a complicated scenario I am still trying to get head around x

Are you aware that after being on carbimazole you may be taken off it and then may relapse? Are you aware that if untreated a thyroid storm may cause death?

Most common symptoms of being overactive are bone thinning, hair loss, night sweats, racing heart beat and palpitations, overheating, overeating, weight loss or weight gain, exhaustion, depression, diarrhea, swollen limbs, joint pain, headaches, neck and shoulder pain , anger and rage and other mental health issues, thyroid eye disease, thickening of leg skin and reddening, relationship breakdowns and lack of friends to name but a few. Then there is anaemia, inbalance of vitamin D, B12, C or problems with adrenal glands.

Then there may be nodules, goitres, sore throats and some on here have had worse.

Just for your information.

tilly83 in reply to greenginger

I am and it's a very depressing list.

BillieSt in reply to greenginger

a question greenginger, I've developed a painful ache in the lower part of my right leg. Could this be another symptom or could I just have overdone the pilates?

greenginger in reply to BillieSt

Yes but pain in the lower legs can be related to low iron levels and or vitamin d levels.

I agree with green ginger. Last May l was seriously ill. I made excuses for all my symptoms before it totally spiralled out of control. I had every symptom of graves. The endo thinks l had had it for at least a year. That's why it is important to be monitored closely and listen to your body and if need be continually at the doctors so be it!

tilly83 in reply to Tory

Thanks I agree, I think its gone on a lot longer, first had problems in 2010 but bloods fine and do wonder if I've intermittently had it since I had first child, lost a lot of weight and got palpitations but put it down to stress, I think it can come and go but obviously older (no wiser!) and more affected x

greenginger in reply to Tory

Thanks Tory, I do not want to be a scare monger but I was ill for about 5 years since the birth of my middle child.

I had high blood pressure but as I suffered preeclampsia during pregnancy was ignored. Then I found work unbearable as I could not think and at times found I could barely put my words together. I was always really angry and had a shocking memory. I had hot sweats and was not then 40. I thought I was having a heart attack or panic attacks. I then had my 3rd child and then my body fell apart.

I am 43 and feel 93 most days. My endo is rubbish and says my bloods are fine. Some days I ache all over or have oedema in my hands or carpal tunnel in my wrists. My periods are very heavy and painful and I look old and saggy faced, puffy.

I have no energy and have on average 3 good days a month. I have lost my career and feel sorry my kids as I am grumpy and tired.My hubby is understanding in his own way but I no longer speak to my family even though 2 of them are hypo. They think I am a drama queen and that they are worse off than I.

I rarely go out except for the school run and although not depressed I am fed up with it all.

Anyhow I hope you are all doing better and are successfully treated.

Tory in reply to greenginger


I get so cross when people think thyroid problems are easily sorted. I am older than you but still frustrated how it has ruined my life. I do't think there is a magic tablet and we are all different how we respond to the treatment. At the moment l do feel better in myself compared with last May but my body and mind just don't work. It's like this week l've just been asked to go on a young friends hen do in January in Amsterdam. The old me would have gone without thinking about it but l've declined as if l'm like this l wouldn't cope. As you said it's not depression it's just not fair!

greenginger in reply to Tory

I know I am already worrying about a wedding in September with old pals and all day drinking and one next April.

They do not understand that I cannot drink these days and need a nap and get tired and have no enthusiasm.

I agree that different people react differently to meds but I have found great support on here for hypo's and a complete lack of understanding for hypers.

Life is pretty poor even when I am having a good day and if I could do anything to solve it I would. Meanwhile back in the real word....... :)

I was diagnosed with graves disease In October 2012, and my endocrinologist suggested block and replace. I did'nt really want to take the high doses of carbimazoles because of the risks, but I had no option really. I took them for 6 months with thyroxine. In June of 2013 I had blood tests and my results were normal. It's nearly a year later and they are still normal. The endocrinologist says It's In remission, because It cannot be cured, so It could recur at any time, but for the time being I'm fine! I would say go for the block and replace, all you have to lose Is time, but It's worth a shot.

Hi I was diagnosed with toxic graves hyperthyroidism 2 mths ago. I'm a 39 female and dare I say I'm a smoker. I had high t levels of t3 25 t4 50 with low tsh 0.02. Still learning what all these numbers are about. My antibodies where at 6 which diagnosed the graves bit. I've been on 40mg of carbimazole and 120mg of propanadol a day for 8 weeks. Bloods now show just below normal levels as the carbomizole is kicking in. Have felt pretty normal through the treatment so far. Hasn't really stopped me doing anything. I have an enlarged right lobe to my thyroid but with no visible signs of enlargement to look at me. So endo has just put me on block and replace and I'm 2 days in to 100mg of thyroxine with 40mg of carbimazole a day. I'm also Slowly dropping the propanadol over the next week. I'm Now feeling a bit strange in my head. A bit fuzzy and my focus is a bit off and I burst into tears earlier. Haven't cried for 6 years! I'm a happy person and full of life normally. So my questions are: is block and replace okay? How does it make you feel ? How often should I have bloods done now? Can I still achieve remission when they stop the pills? Can I be on this regime for a long time? My Endo is already talking about rai in December! Im scared of that. I have never been ill in my life so this one has knocked me for 6. Any general advise welcomed as I'm new to this and don't know what's the best path to take. Ps my neighbour had rai twice and then surgery at 20 yrs old for cancer in his thyroid and he is now on thyroxine for life and all okay with him. Thanks Alex

Ps I'm not someone who enjoys taking tablets either but needs must in the short term. Just not sure I trust my endo is doing what's right for me. Thanks Alex

Hidden in reply to Alexkjones

Hi Alex, welcome to the forum.Now I am no expert like many on here are but I do have Graves.i was diagnosed last November but had symptoms for about 9 months before which wefe put down to menopause! I started just on carbimazole then In January was changed to block and replace on the same as you 40mg carb and 20 mcg thyroxine.I started to feel better after about a month and the propanadol helped with palpations etc.It is normal to be weepy and anxious whilst you are hyperactive it is a symptom of the illness -I thought I was going loopy for a while! Once your lbloods get back into range and you are no longer overactive you will start to feel better.I stayed on block and replace until 2 weeks ago and have everything crossed for remission. I had my bloods done every 2 weeks at girst , then every month then every 10 weeks or Endo prefers block and replace and it does seem the standard first treatment. If I do not get remission I am going to have another go on block and replace.

DO NOT be rushed into having RAI lots of membets have it and regret it as they then go underactive instead of overactive.Put RAI into the search box and look over old posts.Its too early to be talking about RAI once its done its done no going back!

Some people have been on block and replace for years and who knows you may go into remission !

Just a word of warning over smoking, no lecture I have an occasional one, the risk of thyroid eye disease is high in smokers.

If you want to ask anything else I will try to help you and if I dont know someone else will.

just a tip its best to start a new post as it can get missed tagged onto an old one, hope that helps a bit

Kim x

Thanks Kim that gives me some comfort for now.. Thanks for the posting tip too. I've posted as a question as well. No rai for me for now then I think. Just need to give this block and replace a bit of time. Was worried it might stuff me over I read some bad stuff about it. Didn't know whether I should just be staying on carbomizole. Thanks Alex

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