Thyroid UK

How long for medication to leave system?


My son was diagnosed at 13 (ish) with Graves Disease and put on Carbimazole and Thyroxin. His levels were good but the doctors wanted to see if the problem had sorted itself so discussed taking him off the medication. He got bored of waiting (he's 16) and so did it himself on Christmas Eve! He had a blood test at 2 weeks which showed him now as underactive and the doctor said he was to go back to the same dosage?

BUT my question is how long does it take for the medication to leave the system to show a true reading??

I spoke to a friend who is a doctor and has read up since knowing about my son and she said we should wait 6 weeks, we're nearly at week 6 now.

Any info gratefully received :)

3 Replies

Can't really offer any help but I'm interested. I've got Graves too and stopped my carb and levo in early November. I had a blood test at six weeks and have heard nothing since although I was sure the form I handed to the receptionist said to see an endo after eight weeks but I could easily have got that wrong.

Do you know why the doctor wanted him back on the meds because he had become under active? Surely they wouldn't want him to become hyper again? I'm only asking because although I'm in remission I sometimes wonder if I am becoming a bit under active now but I don't know for sure - it's just a feeling.

It looks like six weeks might be significant if that was when I was scheduled for my first post-meds blood test and that is what your doctor friend has said.

I was on a daily dose of 40mcg Carbimazole and 100mcg levo - but I am 65 and I think Graves in older people can be different to Graves in younger people. I do hope he gets the result he wants. Graves is a pretty mean disease - bad enough for adults but I imagine the last thing someone in their teens would want.


In all honesty and with respect I don't think GPs can know it all which is why I was glad my friend did some reading up on it. I think our GP just saw the result and had a 'knee jerk' reaction to it :(

We're off to see him on Friday so I think we'll 'battle' it out then and try to sort what the next step is, I just wanted a few other opinions and as you had to have a 6 week blood test I would guess that sounds right.

I can only imagine if you had a blood test and have heard nothing that your results were fine but I was told, by the specialist at Alder Hey, that a test should then be done at 2 week, then month, then 6 month interval in case of relapse.

I do hope your Graves has rectified itself and you suffer no more ill effects of it. It turned my lovely boy into a monster who was telling us to 'go away' but in stronger terms, not like him at all!! He can be as bad as the next but he was never rude :(

Good luck x


Oh I can imagine - I was so aggressive at times, no patience at all. One day I was standing waiting for a park and ride bus, there were half a dozen pensioners in front of me, the bus arrived, the driver sat and hooted his horn at a car who had decided to stop in the bus bay so he clearly wasn't in a great mood, everyone got off and the pensioners just stood there talking, one was playing with his mobile phone. Eventually I could contain myself no longer and said to them, 'Are you going to get on this bus or A&E you waiting for something else? Because if you don't get on he'll go without us!' They looked at me and headed for the bus, the guy who had been playing with his phone muttering about people who were in a hurry. My husband was mortified. Then in Tesco I found myself having to hold my tongue when I had the urge to ask people if they were going to stand chatting right in everyone's way or could they just give other people a break. I was grouchy, angry, tired out and tearful. It was like the world was my enemy. I had to replace my Kindle and I cried when I couldn't get my new updated one to work. I sent the support people an email asking for help and said NOT to phone me up ( they have done in the past) because I would just end up crying about it all. My lovely son went to Amazon and sent me a book on how to solve my problems.

The good news is - I went back to normal - or as normal as I'm ever likely to be. So stick with him, I'm sure he doesn't mean to be horrible, he probably feels awful - then throw in a few teenage hormones ( at least I didn't have to worry about that!) and it can't be any fun for him. Try not to worry too much, I'm sure your 'monster' will be back to your lovely boy again. :-)


You may also like...