Accidentally took 50mcg instead of 100mcg levothyroxine for a month!

[Racheeeel78]

Hi everyone,

I have been taking 50mcg of levothyroxine a day instead of 100mcg which is my correct dose (I also take 10mcg T3).

The packets were identical and I have been taking the 50mcg all month and only realised when I put the empty packet into the bin (I had a mixture of 100mcg, 50mcg and 25mcg In my medicine box from when finding correct dosage in the past).

How will this affect me?

And should I just take my 100mcg as normal?

so annoyed with myself. 😫

[SlowDragon Administrator]

Surprised you didn’t notice symptoms returning

Get back on 100mcg every day and retest in 6-8 weeks including vitamin levels

[Racheeeel78 in reply to SlowDragon]

I’m currently two weeks into whooping cough so less likely to notice symptoms.

I’ll book blood test for 6 weeks and hopefully haven’t caused too much havoc 😫

[TiggerMe]

Better to go to 75mcg for a good few weeks before getting back to 100mcg, though if you haven't noticed any difference you wonder if you shouldn't test now to see where your levels are? No sense in taking it if you don't need it

[Racheeeel78 in reply to TiggerMe]

I had bloods done a month ago and was slightly over replacing but I felt fine (tsh 0.4). I currently have whooping cough so probably less likely to notice under replacement symptoms as been resting a lot!

I’ll take 75mcg for 6 weeks and then book a blood test. Thank you

[DippyDame in reply to Racheeeel78]

Are you baseing " over replaced" on TSH result?

If so the result will not be reliable.

For one thing you are taking T3 which lowers both TSH and FT4.

For reliable results you need to test both FT4 and FT3.....though medics just don't understand this, or the science behind it.

Lowering your levo dose as you did for a month would normally have an impact.

Something definitely wrong with your dose.

Do you have any symptoms?

Suggest a full thyroid test to include...

TSH, FT4, FT3, vit D, vit B12, folate, ferritin and thyroid antibodies TPO and Tg

I would return to your original dose (which must be steady) then retest in 6/8 weeks

Sorry about the whooping cough....take care.

[Racheeeel78 in reply to DippyDame]

I had a private endocrinologist so all levels tested, including folate, vitamin D, iron etc. I have Hashimoto and my antibodies are at 60.

It was only marginal replacements and he said if I feel okay, we can retest in a couple of months.

Really strange that I didn’t feel the difference?? I suppose my feet I have felt a little bit colder than they have been but as far tiredness brain fog, I’ve not really felt any different…

[Noelnoel in reply to DippyDame]

For one thing you are taking T3 which lowers both TSH and FT3

Do you mean it lowers TSH and FT4?

[DippyDame in reply to Noelnoel]

Yes, I do mean that T3 lowers both TSH and FT4

Thank you for pointing out that careless typo.

Error corrected!

[Noelnoel in reply to DippyDame]

Not a problem. Easily done, at least it is for me

[greygoose]

Same thing happened to me, more or less. The pharmacist gave me 75 mcg instead of 175 mcg. And, as the boxes were more or less the same colour, I didn't notice for four weeks.

What happened was that I became more aggressive - Nay, homicidal! lol But as soon as I got back onto my correct dose, I was back to my 'normal' self. What really, really annoyed me was when I went back to the pharmacy and told her what happened, she had the nerve to say 'well, it's only a small difference'!!! How can they be so ignorant!?!

But, anyway, don't worry about it, it didn't do any permenant harm.

[TopBiscuit in reply to greygoose]

"What really, really annoyed me was when I went back to the pharmacy and told her what happened, she had the nerve to say 'well, it's only a small difference'!!!"

😮 It's frightening, what comes out of the mouth of people who should know better.

[greygoose in reply to TopBiscuit]

It sure is! I had a friend who's endo was on holiday. The replacement allowed her TSH to go up to 4. She told the replacement that her usual endo liked to keep it below 1 and the replacement said... you've guessed it! 'Oh, there's not much difference between 1 and 4'!!! It would be funny if it weren't so serious.

[Racheeeel78 in reply to greygoose]

Thanks for the reassurance- hopefully will be okay going straight back to 100mcg.

The pharmacy lady - so frustrating if she’d given you more instead of lower does could have caused really scary symptoms. Glad all was okay. I’ll definitely doublecheck the packet going forward lesson learnt. 😫

[greygoose in reply to Racheeeel78]

Yes, you just can't trust anybody these days!

[Buddy195 Administrator]

I have made the same mistake one week with accord 50 and 100mcg as the boxes are so similar.

If you have any adverse effects moving from 50-100mcg, I would take 75mcg a day initially & build up slowly to 100mcg.

I personally prefer to wait 8 weeks on a consistent dose of 100mcg before rechecking levels.

[Racheeeel78 in reply to Buddy195]

This is exactly what I did, boxes are identical! Glad you realised after a week! I might alternate 100 & 75mcg for two months then go get bloods taken as was slightly over replacing!