Hi I am new to this forum. I have had underactive thyroid for years and then suddenly had unexplained breathlessness. After a stay in hospital the Dr discovered that I was overmedicated with thyroxine and was now suffering from overactive thyroid. Dose is gradually being reduced.
Has anyone had severe breathlessness with too much thyroxin?
Too much levo cannot make your thyroid over-active. That's not how it works. You could be over-medicated, but only if your FT3 is well over-range. Did he test your FT3? What did he test? Have you got the numbers: results and ranges? If so, post them on here and let's have a look. 
Also important is to test your key nutrients: vit D, vit B12, folate and ferritin. Low nutrients are far more likely to cause breathlessness than high T4.
Thanks, I think I badly worded this! I have low TSH of 0.157mu/l and highFT4 26.15pmol/lNormal range TSH 0.27-4.2 and FT4 12-22.0
I was taking 175mg Mon-Fri and 150mg over weekends. I am now on 150mg Mon-Fri and 100mg at weekends.
Was test done early morning and last dose levothyroxine 24 hours before test
Still doesn’t show over medicated …..it “possibly” shows slightly over range Ft4…..if last dose levothyroxine was 24 hours before test
No Ft3, vitamin D, folate, ferritin and B12
You’re only over medicated if Ft3 is over range
Many many thyroid patients have low or suppressed TSH when adequately treated
Teva brand levothyroxine upsets many people
Teva is only brand that makes 75mcg tablets
Request GP test full iron panel including ferritin, vitamin D, folate and B12 NOW
That’s a ludicrously huge reduction in levothyroxine dose
Dose should only be reduced by 25mcg per day maximum….even that likely too much …..often very difficult to tolerate more than 12.5mcg reduction at any one time
Thanks. My dose was reduced by 25mg for 6 weeks then I was re-tested and it was reduced again. I had all bloods done three times and all were normal however I will get D, Folate and B12 done just encase. I dont know my FT3 but I am seeing an endocrinoligist who wants another test in three weeks.
How long have you been on this reduced dose? And, is your breathing any better?
Hi Forever59 🤗
Don’t get doctors suck you into the ‘normal’ term.
This is just a general comment on results and how to look at them.
You do need to know your FT3 (the most important measure) as well as FT4 and last and least important of the three TSH.
Also you don’t need to be ‘normal’ you need to be optimal. You also have to understand that your results may look good on paper, but you may feel awful. We are all different.
Sometimes we have to make a choice between keeping the doctors happy staying within their ‘normal’, or actually being well.
It is important to distinguish between ‘normal’ and optimal. The term ‘normal’ (note my use of the inverted commas) it is a misused term that you should be wary of. What should be aimed for is OPTIMAL.
Only two little words, but they mean very different things. In fact one could say ‘normal’ is meaningless. GPs who don’t know what they are doing generally tell you that you are ‘normal’ if you are in range.
Symptoms should be the MOST important diagnostic tool, but it sits at the bottom of the list as an annoyance. Nothing annoys a doctor more than having a lovely set of blood results, all ‘normal’ and the damned patient goes and spoils it all by having symptoms! 😂
Ever been told by a GP “Your symptoms should have cleared up by now” or something similar - because your results are “normal”?
The trouble is the majority of GPs (and some Endos) don’t understand what the range is there for - it’s a Guide - not a diktat.
Sadly most think the range is a ‘cup’ and that the patient is a ‘ping-pong ball’ and if they get the ping-pong ball in the cup they win a prize.
For instance re Levothyroxine- you can be on completely different doses at either end of the range and be hypo (at the lower end) and be optimal and well (at the upper end) OR, heaven forbid, because of other confounding factors you may sit outside the top of the range before you feel well OR (panic stations) the range might not apply at all! 😱😂
This is why forum members will ask you to post results WITH ranges. These guys are good at interpretation- they don’t play ping-pong.
Good example is
I was hypo, but in range and I only started to feel well when I got on to 150 µg of levothyroxine, yet if the doctors had had their way they would’ve stopped dosing me at 75 µg. I had to fight for every dose increase (doctors love ‘ping-pong’)
I am 5’ 8” and 15 stone and I have a friend who does very well on 75 µg, but she is 4 ‘ 11” and 6 1/2 stone.
Hopefully this adds some context to looking at your results and to be cautious of accepting a GP’s interpretation.
I had all bloods done three times and all were normal however I will get D, Folate and B12 done just encase.
You need ferritin and iron tested too …..
“Normal” is not a result …..You need actual results and ranges
You are legally entitled to printed copies of your blood test results and ranges.
The best way to get access to current and historic blood test results is to register for online access to your medical record and blood test results
UK GP practices are supposed to offer everyone online access for blood test results. Ring and ask if this is available and apply to do so if possible, if it is you may need "enhanced access" to see blood results.
Link re access
healthunlocked.com/thyroidu...
In reality many GP surgeries do not have blood test results online yet
Alternatively ring receptionist and request printed copies of results. Allow couple of days and then go and pick up.
Important to see exactly what has been tested and equally important what hasn’t been tested yet
Bloods should be retested 6-8 weeks after each dose change or brand change in levothyroxine
For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.
Very important to test vitamin D, folate, ferritin and B12 at least once year minimum
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water and last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins
List of private testing options
thyroiduk.org/getting-a-dia...
Medichecks Thyroid plus antibodies and vitamins
medichecks.com/products/adv...
Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test
bluehorizonbloodtests.co.uk...
If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3
£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code
thyroiduk.org/getting-a-dia...
NHS easy postal kit vitamin D test £29 via
Very common for low TSH to drop even lower if dose is reduced…….essential to always test Ft4 and Ft3
Yes I had exactly same problem. My dose was also too high it showed up as tsh being too low. I was on 100 Levo a day and after blood test showed tsh too low my dose was reduced to 75 within weeks my breath issues stopped and on bloods being run am back in the normal range. I cannot stress how important it is to get bloods done at least once a year. I had given up smoking and milk and reduced my caffeine during covid and all these changes had affected my Levo absorption so I needed less. The breathlessness was horrendous really scary actually I felt like I couldn’t get full breaths it had lasted a year I thought I must have heart problems I struggled to walk up small hills. I had aches in my legs felt like an old lady when I got up in the morning. I had itchy skin syndrome it’s called formication as well too much Levo increases anxiety you see. I also had bouts of vomiting every 6 to 8 weeks that kept me bed bound for 24 hours literally sicking up my guts. I also had palpitations. It’s equally as dangerous too have to much Levo as to have too little. And I had all my vit levels checked and platelets and all was fine only Levo range was out.
OK, so your FT4 was very high. But, you didn't have your FT3 tested, so you don't know if you were actually over-medicated, or just a poor converter. The TSH is irrelevant.
Do you have Hashi's? Your high FT4 could have been due to a Hashi's swing, rather than your dose. Because if you just stayed on the same dose and your FT4 suddenly rose like that, it wouldn't have anything to do with your dose.
Welcome to the forum
Breathlessness is frequently low iron/ferritin and low vitamin levels are extremely common on levothyroxine
How much levothyroxine were you taking when admitted to hospital
Have you got the actual results and ranges from these tests
ALWAYS test thyroid levels as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test
Just testing TSH is completely inadequate
Do you always get same brand levothyroxine at each prescription
Essential to test vitamin D, folate, B12 and ferritin at least annually
What vitamin supplements are you currently taking
For good conversion of Ft4 (levothyroxine) into Ft3 (active hormone) we need OPTIMAL vitamin levels
Forever59
What were the test results showing when you were told you were overmedicated? Can you post them on the forum along with their reference ranges please.
What dose of Levo were you on and what has it been reduced to?
Were any other investigations done to see if there was a cause for the breathlessness?
Breathlessness can be caused by hypothyroidism/undermedication, low ferritin, iron deficiency, heart problems, lung problems so it would be beneficial for all these to be checked rather than just blame thyroid medication.
Hi, I have been in and out of hospital and had my heart and lungs thoroughly checked. All general bloods are fine so i'm thinking it could be thyroid problems.
Please add most recent vitamin results
Or come back with new post once you get new testing and results via GP
Forever59
You're only overmedicated when FT3 is over range, so unless they've tested that you wont know if you're overmedicated.
Interesting that you mention brand of tablets- I think I have had different brands from different pharmacies
Forever59,
Welcome to our forum.
I used to get breathless if FT4 levels rose too high when medicating Levothyroxine mono-therapy. No matter what dose I took I still felt unwell, and it became scary when after raising dose to high/over range levels, symptoms increased and then wouldn’t reduce even when med dose was lowered. My breathlessness always went with heart palpations.
A proportion of the thyroxine we take should be converted to T3 when meds are working effectively. T3 is the active hormone that brings us well-being. However, when we take too much thyroxine a larger proportion can get turned into reverse T3, and the enzyme that makes this happen (deiodinase 3) at the same time also converts our precious T3 to an inactive form of T2 called 3,3′-T2.
Therefore, we become hypothyroid on a cellular level no matter what our labs say. Breathlessness and ‘air hunger’ when we feel we can’t inhale enough oxygen even though our lungs are opening enough, are both symptoms of inadequate thyroid hormone which reverse when thyroid hormones can eventually work effectively.
Levels of reverse T3 can also be increased by elevated cortisol, oestrogen dominance, inflammation, depression, other medications, etc, and iron deficiency which can also cause breathlessness independent of thyroid hormone levels. It can be tricky unpicking what is causing what but with FT4 results over range it looks like you were over-medicated on thyroxine.
It's good you have reduced dose. Reverse T3 can take a while to clear and meds won't work effectively until it reduces enough but ensuring iron/nutrients are optimal will help. If you post new thyroid hormone results complete with ranges (numbers in brackets) members will comment on levels.
I had breathlessness when my Levothyroxine dose was over the range. At that point I was only on Levothyroxine treatment for Hashimotos. My GP had recently told me to increase my Levo dose. My heart rate dropped into the 30’s. I was taken to hospital as I collapsed. They did my TSH, T4 and T3. My TSH was suppressed. My T4 was over the range and my T3 was very low but just in range. I was only converting 8% of Levothyroxine T4 to active T3. Still no T3 help from the NHS! I finally went private and also did the DIO2 gene test which came back positive. After going private I was prescribed T3 medication plus Levothyroxine. I’ve had no issues since. T3 introduction was my game changer.
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