Thyroid UK
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Levothyroxine

Hi I have been on levothyroxine for 25 yrs. Dosage 150 mg. I also have atrial fibrillation. 1 year ago after an emergency visit to the ER and overnight stay in hospital the cardiologist reduced my dosage to 125mg, and I have had no AFib symptoms since. 2 months ago my blood test showed me under treated and the dosage increased again. I agreed with my GP to increase it but would decrease if my AFib reared its head again. This has happened and I have decreased the dose, have an appointment on Friday with the GP. Can someone tell me if they have AFib and find other drugs better, if so which ones. Despite being hypothyroid for 25 yrs I have never se

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I have never seen an endo or had test to find out why my thyroid failed

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I have had better advice and more courteous and respectful treatment from cardiologists than from most Endocrinologists I've seen.

You could ask for thyroid antibodies TPO and TgAb to be tested to find out whether you have autoimmune thyroid disease. If the disease has progressed to the point of destroying all your thyroid I understand that the antibodies may not be present anymore. Maybe someone more knowledgeable than me on this point will comment.

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Thank you , I have telephone appointment with my G P on Friday so gathering info

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Eileen,

If 125mcg is not enough and 150mcg is too much suggest to your GP 125mcg/150mcg alternate days which averages 137.5mcg daily.

NDT and Liothyronine (T3) are alternatives to Levothyroxine but they aren't necessarily better, simply different, and are no more or no less likely to trigger atrial fibrillation. NDT is not licensed for use in the UK so won't be prescribed on the NHS. T3 needs to be recommended by a NHS endocrinologist before most GPs will agree to prescribe. T3 can have more of an effect on the heart than Levothyroxine so your cardiologist may not recommend it.

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Thank you

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Also just to add to the mix, the majority of people who have atrial fibrillation do not have hypothyroidism. If you have been stable on a dose of levothyroxine with blood levels in range, it may be that you have just developed af despite being on levothyroxine not because you are. Just to put that out there not everything is because of thyroid disease.

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Hi I didn't say that the AFib was caused by the thyroid disease, I have had an under active thyroid for 25 yrs. And AFib for7 yrs I am a nurse and know that although it is possible that AFib is not necessarily caused by an under active thyroid. What I said was a year ago my dose was too high and caused problems but is now too low.

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Sorry must have misread as I interpreted your post that you had been on 150mcg for a length of time and spontaneously developed af. It didn’t mention any time frames. Hope you get more stable soon.

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Hi, this last point is inaccurate, a number of people with AF have hypothyroidism, including me. It may not be the majority but it is substantial. I suggest you post on healthunlocked af and see what answers you receive.

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Peddling A study reported in the BMJ found: "The current study is, to the best of our knowledge, the first to assess the association between the whole spectrum of thyroid disease and the subsequent risk of atrial fibrillation in a population of primary care patients. Our main finding was an apparent linear relation between levels of thyroid dysfunction and atrial fibrillation risk—that is, a low atrial fibrillation risk in hypothyroid patients, a high risk in hyperthyroidism, and a TSH level dependent (a dose-response relation) increased risk of atrial fibrillation in all levels of hyperthyroid disease, even in high normal euthyroid subjects."

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Further to my earlier comment, I take 75 mcg s thyroxine daily but consult an alternative practitioner who has prescribed additional supplements.

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From my experience, I was dosed with Levo which made me very ill and went onto T3 with the advice of Dr P. Last year and the year before I've had heart problems and had a pacemaker fitted before Christmas. After doing some research on the subject I'm sure that during the period of time when I was on Levo and it was building up in my body and not being used and making me toxic the lack of T3 actually damaged the electrical impulses in my heart . T3 is vital for the smooth running of the heart. I'm now feeling very much better.

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In exactly the same place as you. Used to take 125 Levo no problem reduced to 100 because TSH 0.03 and Dr worried. Back up to TSH of 1 so talked another Dr into putting 25 back. Now having lot of episodes of Afib, sometimes twice a day so have to take Flecainide. I have decided to stop the 25 Levo but now the brain has gone awol.

Di

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