Cardiac side effects T4 vs T3: I am getting... - Thyroid UK

Thyroid UK

137,135 members160,811 posts

Cardiac side effects T4 vs T3

fred1e profile image
16 Replies

I am getting ventricular premature contractions when I try to take T4 only....even on a tiny 25mcg dose. My heart rate stays low (50s). There is no atrial fibrillation.

Has anyone else had this, and found a difference on T3supplementation.

Written by
fred1e profile image
fred1e
To view profiles and participate in discussions please or .
Read more about...
16 Replies
SlowDragon profile image
SlowDragonAdministrator

Looking at previous posts..you are coeliac and results suggest probably Hashimoto’s

What vitamin supplements are you currently taking?

As Coeliac (and Hashimoto’s) low vitamin levels are extremely likely

We need optimal vitamin levels for any thyroid medication

Have you had recent tests of vitamin D, magnesium, folate, ferritin and B12

fred1e profile image
fred1e in reply to SlowDragon

Hi...yes...definitely Hashimotos, confirmed by ultrasound scan.

Active b12 128 (>37.5)

Folate 14.2 (>3.89)......I think these are fine.

Vit d I know is low at 60 (>50)... but I had to stop all supplements as needed to work out what I was reacting to!

Ferritin 222 (13-150).... it's been this high for over 6 maths.

My latest thyroid figures are definitely odd....NOT taking any thyroxine at time test taken:

TSH 1.64 (0.27-4.2)

FT4. 10.4 (12-22)

Ft3. 3.79. (3.1-6.8)

Endo doesn't think it is central hypothyroidism as my other hormone levels normal, my T3 used to be around 5 with a T4 of 12-14.... so reasonable conversion.....but something is going on !.

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

Well if ultrasound confirms Hashimoto’s you are going to need thyroid hormones

TSH is frequently extremely unreliable with Hashimoto’s

Dosing according to Ft4 and Ft3 results is essential

Which brands of levothyroxine have you tried?

Low magnesium is extremely common when on gluten free diet and with Hashimoto’s

Magnesium is essential for good heart rhythm

Personally I couldn’t tolerate vitamin D supplements until improved low magnesium levels

Magnesium blood test is pretty useless...it only measures what’s in blood not cells and never comes back out of range

Many many people on here supplement magnesium

fred1e profile image
fred1e in reply to SlowDragon

Mercury...is the only brand of T 4 I've tried...but I have got some Actavis ones too.

I have tried to take magnesium, but found I couldn't swallow the large tabs (mag. bisglycinate 500mg), and they didn't help my gut!

Can you recommend a good, easy to take magnesium, and also a good vit d3, as I must start that again....I would prefer a liquid/ spray including k2.... but can't find a high dose one that doesn't taste of peppermint which I loathe!!.

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

Vitamin D mouth spray ....as far as I am aware all are peppermint flavour

SeasideSusie recommends a gel vit D

Magnesium

Cheap and easy to use is Calm vitality magnesium powder. You mix it with warm water as a drink. Good if tend to suffer constipation. Best to start on low dose, increase to tolerance ...too much can cause diarrhoea

Personally I now use ReMag - developed by Dr Carolyn Dean who wrote The Magnesium Miracle. It’s a liquid. Not cheap! But doesn’t upset gut at all.

Both are available on Amazon

All magnesium and vitamin D you swallow must be minimum of four hours away from levothyroxine

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

Many people find Levothyroxine brands are not interchangeable.

Once you find a brand that suits you, best to make sure to only get that one at each prescription.

Watch out for brand change when dose is increased or at repeat prescription.

Many patients do NOT get on well with Teva brand of Levothyroxine.

But Teva is a Marmite brand...some people can only tolerate this one

Teva contains mannitol as a filler, which seems to be possible cause of problems. Teva is the only brand that makes 75mcg tablet. So if avoiding Teva for 75mcg dose ask for 25mcg to add to 50mcg or just extra 50mcg tablets to cut in half

Teva and Aristo are the only lactose free tablets

healthunlocked.com/thyroidu...

Teva poll

healthunlocked.com/thyroidu...

GP or Endo can prescribe liquid levothyroxine....worth trying if you don’t get on with any tablets

thyroiduk.org/tuk/treatment...

fred1e profile image
fred1e in reply to SlowDragon

Thanks...I know I will/do need some form of thyroxine....unfortunately given the level of ectopics I get....over 20% of beats over a 24 hour period...I doubt it's just the brand....hence wondering about T3instead..

I'll try that magnesium in case...and if anyone has any recommendations re a non peppermint d3....?

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

My ectopic beats stopped after starting on magnesium

Mitral valve prolapse is common with Hashimoto’s

verywellhealth.com/mitral-v...

fred1e profile image
fred1e in reply to SlowDragon

Interesting!.

Echo and CT were clear, no sign of any valve issues...they think it is purely electrical, but I'll definitely try it !!

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

Ectopic common when hypothyroid

healthunlocked.com/thyroidu...

healthunlocked.com/search/p...

Angel_of_the_North profile image
Angel_of_the_North in reply to fred1e

My ectopics were even worse than that until I improved my FT3. I don't know why doctor think it's not central hypo - it's possible to have a faulty TSH response without all other hormones being out of range. I had low cortisol also, but not low enough for NHS to treat.

SeasideSusie profile image
SeasideSusieRemembering in reply to fred1e

fred1e

This company doesn't make a combination supplement but both the D3 drops and the K2-mk7 drops are orange flavoured:

amazon.co.uk/Vitamin-d3-Liq...

amazon.co.uk/Vitamin-K2-Liq...

I use Doctor's Best D3 softgels which contain just D3 and extra virgin olive oil, very small gel caps.

SlowDragon profile image
SlowDragonAdministrator

Starting on too low a dose of levothyroxine can make symptoms worse

Standard starter dose of levothyroxine is 50mcg unless over 65 years old

fred1e profile image
fred1e in reply to SlowDragon

I did originally start on 50mcg. but after 10 days, my heart went in to bigeminy....HR was 36 with an ectopic beat in between each normal beat....had to stop taking it!

When I tried 25 mcg , it just increased the frequency of ectopics to a more moderate level....unfortunately I seem to have an extreme reaction!.

SlowDragon profile image
SlowDragonAdministrator in reply to fred1e

Some people do need to increase dose very very slowly, especially if been hypothyroid for long time

Angel_of_the_North profile image
Angel_of_the_North in reply to fred1e

My heart rate wasn't that low, but i was having regular runs of 4 or 5 ectopics not just bi and tri gemini until FT3 was at least 50%. But cardio said it was not life threatening- and it wasn't

You may also like...

T4 added to T3 only… repercussions/side effects

T3 Only vs T3 & T4 Just wondering… if anyone like me… finally enjoyed T3 only…. w dosage gradually...

Levo t4 vs t4 and t3 treatment

to do well on levo t4 only? I was on armour before and many people talk about only doing well on t4...

Is Itching a side effect of high T3 low T4?

I am trying to get my specialists advise but covid has put a delay on any appts. The only other...

T3 medication side effects

of ankles, does anyone know or have had similar experience? A side note I do have low morning...

Side effects of Liothyronine T3.

last time as I’d had a reaction to taking T3. This reaction was within seconds of taking the...