Beta blockers and thyroid hormone conversion

[sobs1962]

Does anyone know what the maximum dose of Propranolol or other beta blockers that can be prescribed without it causing serious thyroid hormone conversion issues. I've just been to hospital to have an ecg as I have constant tachycardia. The nurse had the leads on for approximately 30 seconds, which I think is far too short a time to get an accurate reading. However, I get the impression they are going to want to put me back on beta blockers as they are concerned about my constant rapid heart rate. I wouldn't mind but it's taken me 14 months to get off propranolol as did it very very very slowly. If I must take beta blockers, then so be it, but not at the expense of my thyroid.

[SeasideSusie Remembering]

sobs1962

There is lots of information about Propranolol affecting conversion of T4 to T3. I am taking Bisoprolol (very low dose) and I can't find anything about this affecting conversion. It is a different medication, although still a beta blocker, in that Propranolol is Propranolol Hydrochloride and Bisoprolol is Bisoprolol Fumarate. Just a thought as to whether they could use Bisoprolol instead if it's suitable for you.

[sobs1962 in reply to SeasideSusie]

I don't know for sure that they will want me to go back on Propranolol but I refuse to feel worse because of a drug that isn't necessarily working. Will just have to wait and see what ecg shows. They don't seem to understand that it's probably my anxiety that's causing my rapid heart rate and I know that it's not good for your heart to be constantly racing but I will not accept a trade off which involves my thyroid being even more dysfunctional than it already is, as we all know what the consequences of constantly undertreated hypothyroidism are.

[SlowDragon Administrator]

If you need beta blocker, you can be prescribed a different one, not propranolol

There are several different options

nhs.uk/conditions/beta-bloc...

[Barrister]

I have suffered with sinus tachycardia for most of my life but when it was constantly above 130 it got very uncomfortable so I was prescribed Bisoprolol. It’s made a huge difference and I’ve not noticed any issues with my thyroid medication (T3 only).

[sobs1962 in reply to Barrister]

Oh that sounds dreadful, but I'm on Levothyroxine only and have been for almost 20 years, my thyroid has been very unstable over the last 2 years or so and is probably due to chronic stress which I've suffered from all my life but can and will inevitably affect my heart at some point. Will refuse to be put back on Propranolol again if they suggest it and ask them to put me on another beta blocker that doesn't affect thyroid hormone conversion, but if they don't think it's necessary, I'll just keep going as I am with a high heart rate(90+) and hope in time it settles on its own.

[SlowDragon Administrator in reply to sobs1962]

High heart rate can be due to being under medicated

Most medics think it’s over medication

What are your most recent thyroid and vitamin results and ranges