Do beta blockers interfere with thyroid meds?

Hi, I've just spend 4 days in hospital with atrial fibrillation. I have m.e and am on 80 mcg of t3 only for my hashis. I've been prescribed bisoprolol beta blocker in the short term, hopefully, while we try to pin down what caused it. It has now stopped. Does anyone know about the interactions of this drug with thyroid med and or hypothyroidism, thanks.

21 Replies

  • Sorry can't answer question but my husband has.AF and the Dr at hospital gave him to higher dose at first it only came to light after he'd had a local for an op when the nurse tried to sit him up (he had to be flat for 3hours after) that his blood pressure was all over the place she questioned his dose it has now been halved! Dr said it's trail and error we can joke now Dr.makes error.while he trails it but luckily (only due to a good nurse) there was no error. So I would suggest if you feel blood pressure or effects of high or low) yuu shout sooner rather than later. All the best

  • Beta blockers are sometimes prescribed in early hyperthyroidism to protect the heart (and they will reduce other symptoms). I've read that they interfere w conversion from t4 to t3 but I believe they are also used when t3 is too high, though if that's because they act directly on t3 or because they relieve symptoms I don't know.

    Is there any chance the doctors think you're on too much t3 so are using BBs for the purpose of dealing w overmedication or are they using it to regulate your heart rate?

  • They are using it to regulate heart. Have briefly talked to endo when I was in hospital about reducing t3 to get my tsh out of suppression as that is the perceived risk factor, but as I also have m.e I know my body does some very strange things. He has kindly allowed me to think and decide what I want to do, thankfully he hasn't said right I'm stopping your t3 which is very supportive of him.

  • Sulamaye,

    Beta Blockers do reduce T4 to T3 conversion.

    The Rotterdam Study finds no association between TSH and atrial fibrillation.

    There is increased risk of AF when FT3 is over range for a long time which is why it is recommended FT3 remains within range.

  • Thank you clutter that's interesting, however it would depend what they were looking for. To really know a suppressed tsh was not a risk factor the study would need to have half its subjects in suppression and half not and then compare AF incidents whilst using comparable ages etc. So although that study may identify that over range FT4 is a trigger it doesn't necessarily exclude suppressed TSH. They did nt seem to consider t3 levels. I am too tired to read more than the summary.

    Although logically it would seem to me that over range t4 and t3, so actively in a hyper state, would be more logical in causing over stimulation of the heart pushing it out of sinus rhythm. Thank you though the evidence that ft4 can play a part would lead me to consider I am over medicated at the moment as a possible trigger. The problem as ever is balancing hypo symptoms with medication intake and having m.e makes that so much more complex to identify what is what and cause and effect.

  • Some beta blockers are known to interfere with thyroid function. A doc put me on propanolol soon after my celiac-triggered hypothyroidism. Didn't find out till much later it lowers thyroid. You could try googling "thyroid bisoprolol".

  • Thanks, I tried googling but couldn't see anything obvious, am a bit shattered to say the least so know how knowledgable so many are here, thought this might be a quicker route to some good info. DId you take your beta blocker away from your thyroid meds?

  • I discontinued the beta blocker. This was before I had a diagnosis of hypoT.

  • Do you know of any beta blockers that don't interfere with thyroid function?I find them helpful in tiny doses for anxiety,occasionally.

  • Have not researched that! I used propanolol for a few months, but finally went off it because I could not tolerate the side-effects. It was only much later that I learned about the thyroid association. And NOT from a doctor. ☹️️

  • I suspect they all interfere with medication for an underactive thyroid.Am trying to sort my adrenal issues.In the meantime,will occasionally use half a 2mg of benzodiazapan when my morning anxiety gets too much to bear.Am also trying the amino acid taurine.

  • Being hooked up to a monitor the whole time I was in the hospital meant the impact of the beta blockers was being witnessed. My blood pressure has dropped and my heart rate can drop to as low as 55 but my heart rate was around 58-62 anyway, so it's hasn't made much difference. I will keep vigilant though. Thanks.

  • Propranolol is used to treat thyroid storm specifically because of its action in blocking conversion of prohormone thyroxine (T4) to triiodothyronine (T3)

  • Hi Sulamaye-I have read several times on here recently that AF can be caused by taking too much T3.80mcgs is quite a high dose,isn't it?I am on 55mcgs but I am 5ft 10 tall & weigh over 11 st.I am experiencing anxiety & depression after 18 months of improved energy & mood,but will be posting my blood results after my tests before attempting a raise,which I may need.

  • Seems to me the Doctors do not understand Thyroid issues. But then we knew that didn't we. I was over medicated a few years ago and I finally had to go to BUPA as my GP said my symptoms had nothing to do with my Thyroid meds. DR at BUPA straightaway said I was very overmedicated.

  • In the case of my endo I think it isn't fair to say he doesn't understand. He has seen someone else have an AF stroke and it was because he made me aware of what to look for that I picked up I was in AF which was very important. There is no doubt that being in AF is a significant stroke risk. My endo is using what he has seen personally combined with research that associates a suppressed tsh with risk of AF. I think nearly all doctors would get me off t3 immediately terrified of being responsible for potentially killing someone. He has not done that, he has given me some information, he says they do not know if it is simply suppressed tsh or over stimulated Medicated that is the risk factor, and he is being vey supportive in treating me like the intelligent human being I am to make my own decision. At the end of the day there is less known than known re thyroid and that includes all of us, not just stupid ignorant doctors, we are feeling in the dark for what is right. I take responsibility for my decision to use t3 and I am grateful to my endo for originally alerting me to the potential dangers. I think everyone here should be aware of that potential risk so they can make informed decisions and keep their eye out for anything dodgy. I don't know if my dose of t3 has caused what happened, I am not convinced it did, but as my endo said at my age etc etc it is the only known risk factor and I need to weigh that up and consider it as a possibility. It was a very frightening experience and terrifying for my ten year old whose granny died suddenly and unexpectedly after being admitted to hospital in the night.

    I am gathering evidence and reasoning cause and effect, I may try dropping my dose and getting my tsh at least with a range and see how I feel symptoms and energy wise. My life is complicated by having m.e/CFS.

    There is also the possibility that I have lymes, I'd taken samento for be first time, and that lymes herxing in the heart triggered the problem. Who knows?

    To me that is the point, none of us know for sure, all I ask for is an endo who admits that and is working with me not against me. I feel very fortunate to have that, especially having some knee jerk GPS in my time who slashed my thyroid meds and made me even iller.

  • In my case I had other symptoms such as anxiety loss of weight. Digestive trouble loss of confidence and panic attacks. also high heart rate. Hope you soon get it sorted.

  • Thanks Sylvia. The problem is I have so many symptoms that are m.e related it is very difficult to differentiate cause and effect. All we can do is do our best, glad you got to be bottom of yours and amazed that an NHS GP didn't pick up over medication as Gary usually see it where it isn't!

  • Despite having a heart rate in the low 40s, I was put on Atenolol, a beta blocker, for a few months. I'd had palpitations, reduced Levothyroxine, and then feeling hypo had high blood pressure which wasn't dropping as expected, when testing at home.

    At the time, I was taking my Levothyroxine at night, and had a visit from the hospital pharmacist about this. In hindsight, this may have been to do with avoiding any interaction between the beta blocker and Levothyroxine, although no specific guidance was given.

    After a very long wait to be admitted, I had had the first dose of Atenolol at about 10pm, followed by Levothyroxine at about midnight. The Atenolol was to be taken in the morning, thereafter. The following morning I experienced what I now know to be central sleep apnoea, which continued while dozing in the discharge ward, and I went on to be supplied with a CPAP machine.

    I reverted to taking Levothyroxine in the morning, with the Atenolol and other drugs an hour later. Despite increasing the Levothyroxine slowly and steadily and past the level where I'd had palpitations (which I believe were due to a newly introduced antihypertensive) my TSH stayed between 3 and 4 until the beta blocker was discontinued.

  • Thanks small blue thing - it's been years since I listened to any Suzanne vega! - I'm hoping that being on t3 only means it won't effect conversion, although looking at how beta blockers work it could be they block cell receptors, but it's not clear from what I've read.

  • This interaction report has the beta blocker at the mercy of the thyroid hormone ;-)[]=major&types[]=minor&types[]=moderate&types[]=food&types[]=therapeutic_duplication&professional=1

    Clicking on the Professional tab reveals:

    Thyroid hormone therapy may reverse decreased hepatic blood flow associated with hypothyroidism. Increased hepatic metabolism and decreased serum levels of some beta-blockers may result. Data are available for propranolol only. No special precautions are necessary. When hypothyroidism is converted to a euthyroid state, a decrease in beta-blocking effectiveness is possible.

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