Racing heart with increased levo dose? - Thyroid UK

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Racing heart with increased levo dose?



I'm newly diagnosed with hashis and have been on 25mcg for levo thyroxine for about 8 weeks which took my tsh from 6.7 down to 4.2. Doctors increased my dose to 50mcg this week. I started taking the higher dose on Friday morning. By lunchtime I had no appetite and didn't on Saturday either. Sat night I started feeling anxious and my heart was racing which for worse and resting heartbeat of 110ish. It finally dropped to 97bpm at about 2:30am and I got to sleep for a few hours. It felt like my heart was going to come out my chest and was super frightening. My heartbeat is usually quite slow. I assume this is the rise in medication. Is it normal and how long does it take to subside?

Should I carry on with 50? I took it this afternoon as was too nervous to this morning.



8 Replies

I know the feeling... have just increased from 50 to 62.5. I am on day 5 and heart rate beginning to behave itself a bit more, and feel a bit less wobbly. Personally, I've decided to persevere as my previous dose (50 t4 10t3) was leaving me tired and cold.

AshleyR in reply to beh1

yeah I'm going to stick it out and see, although if I get another night like Saturday evening i might switch to alternating 25 and 50 for a while.

Sometimes these problems can be caused by not having good levels of vitamins and minerals for the T4 to work within the body and convert into the Active T3.

So have you had the following tested ? - B12 - Ferritin - Folate - Iron - VitD ? If so do post your results with ranges .....

They all need to be optimal. Apologies if you have mentioned these results in another thread. Have not made the time to read :-)

AshleyR in reply to Marz

No B12 or Iron. Ferritin was low normal range (i'm supplementing now) and I'm taking sublingual B complex. I'm being tested for vitamin D next TSH blood test (6 weeks but Dr told me to take a Vit D supplement - not sure if I should start supplementing if I'm being tested for it?!

AshleyR in reply to AshleyR

I mean I havent been tested for B12 or Vit D or Folate. Sorry. Have been tested for ferritin which was low in the normal range.

Marz in reply to AshleyR

I would start the VitD as it is winter ! Still have it tested and then you can adjust the dose accordingly. Around 4500 IU's would be a good winter dose if you are low and then get tested at the end of winter and then do maintenance throughout the summer.

VitD improves the uptake of calcium from foods - so it is advisable to add VitK2 MK7 to your D3 to ensure calcium finds its way to your bones and teeth. Magnesium is also important.

Folate works with B12 - so I am guessing it will be LOW too in addition to the B12. BOTH are very important tests. As I mentioned earlier thyroid hormones work better with optimal levels of vits and minerals.

AshleyR in reply to Marz

thank you


Try 25/50mcg alternate days for a couple of weeks. It works out at 37.5mcg which is a gentler increase. When you are comfortable on 37.5mcg you can increase to 50mcg daily.

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