Thyroid UK

Dosage adjustement help now that T4 and T3 within limits

Hi All,

I have been diagnosed with Graves Disease 9 months ago and finally my latest blood test results (from last week) look like this:

TSH < 0.01mIU/L (0.35 - 4.94)

FT4 13.20 pmol/L (9.01 - 19.05)

FT3 4.60 pmol/L (2.63 - 5.70)

I was very happy to see these results, unfortunately I am without an endocrinologist right now as the one under whose care I was has retired and it will be March before I am seeing someone else. So I am not sure what to do dosage wise, and I was hoping to get some information/advice from the very helpful and knowledgeable members here.

I was taking 100mg PTU every day (50mgx2 - one in the morning, one in the evening) since end of Sep, then when I finished breastfeeding in December I was transferred onto 10mg Carbimazole by the GP based on the recommendations made in the last letter from my retired endo (I actually felt quite horrible after being switched to Carbimazole and in a desperate attempt to do soemthing I did take 15mg one day to see if it was supposed to be a higher dose, but then felt even worse and looked at the Internet to find out that actually 100mg PTU mean 6gr Carbimazole, so I reduced the dose to about 5gr to 6gr day, that is half to 3 quarters of the 5mg in the morning and half to 3 quarters in the evening). Within two weeks of starting Carbimazole I had a massive allergic reaction which in the end the GP, after checking with an endocrinologist from the hospital I was referred to for the March appointment, confirmed to have possibly been brought on by the Carbimazole so I was switched back to PTU. Because of the allergic reaction I was given a shot of Hydrocortisone and then I was on three days of Prednisolone, and the steroids of course they suppressed the immune system. I thought it wise to reduce my PTU dose just in case my blood tests would show reduced values for T3 and T4 and I really fear going hypo. So I have been taking only 50mg PTU since end of December, and have stayed on this now. I do not feel any hyper sypmtoms (feeling hot, irritable, not being able to sleep, palpitations), actually I feel the cold more now, I feel tired in a different way.

The GP now is not sure if my normal T3 result is due to the 2 weeks on Carbimazole or it is the normal evolution after being on anti-thyroid drugs for 9 months, so we are doing another blood test in the beginning of Feb to see if the levels are stable. But he did not advise on new dosage, and I want to get your opinion on what to do.

At my previous results in November, same lab limits, FT3 was slighlty over 6.

Thank you for any advice you might have. I am trying to avoid going hypo and I currently take one 50mg PTU pill in the morning.


2 Replies

Danutza, TSH remains suppressed, FT4 is below half way in range, and FT3 is just below the top third of range you aren't going hypothyroid and should stick with the 50mg PTU dose for now.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

1 like

Thank you for your reply, Clutter!


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