Thyroid UK
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Help please, overdose of levo

I take 150 mcg of levo thyroxine daily. My chemist ran out of my usual brand and gave me, i now realise, a mixed prescription of some boxes containg 50 mcg and some containing 100mcg. I started taking 3 tablets of the 50 mcg but moved on to a box containg 100mcg thinking they were still 50 mcg. For the last 10 days at least i have, unwittingly been taking 300mcg per day. Please tell me what i should do? I feel quite scared. I dont feel hyper but i do feel a bit off colour like i have a cold coming.

5 Replies

Janiebell, you can skip 3 or 4 doses to let the 300mcg doses wash out and then resume 150mcg.


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.


Clutter, thank you so much for your reply. Youve put my mind at rest. Perhaps now i will get some sleep!

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Find a brand that you are happy with and that your pharmacy can get readily and stick with it! I know your extra was caused by being a bit confused but also different brands of the same dose can be different strengths as well so find a brand then ask you GP to request it on your prescription and that rules out one variable you be could be getting.


Yes, Ive taken Mercury Pharma for years and always stick with it but when i picked up my prescription and it was Activis i decided to give it a whirl out of interest. Got more than i bargained for!


Yes I was on MP as well and at one time I decided to safe the NHS a bit of money and instead of getting my 125 and 100 doses all in 25's I also found 4x 25 did not work the same as 1x 100! More years ago before I even knew why I was getting 3 months at a time and found a different brand each time and had to modify my dose. I said this to the pharmacist and she thought the different fillers so suggested I asked the doctor to supply on the one brand on my prescription so we all thought MP as most often supplied and had 100's and 25's. A few years later America said all drugs hat to be within certain ranges so one could be 100+ mcg and another 100- so over a week would make a difference Now it is suggested in some circles that you stick with the same!


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