Racing Heart on Levothyroxine: Hi, I was... - Thyroid UK

Thyroid UK

141,244 members166,489 posts

Racing Heart on Levothyroxine

samimanf83 profile image
6 Replies

Hi, I was diagnosed in Sep 14 with underactive thyroid and put on 50mcg daily. At first I felt amazing on them, effects of which tailed off after maybe 4 weeks but still a noticeable improvement on how I felt before diagnosis. Then in the Dec, bloods were checked and we're still a little high, dose was increased to 75mcg. Shortly into this new dose I started experiencing a racing heart sensation. Have history of ectopic heart beats so tried to ignore those, but it's been persistently getting worse. Every day now my heart can feel like I've been running, for a few minutes or even as long as a full day, it wakes me up on occasions too.

Had cardiologist check me out and they can't see anything wrong. Wondered if it's the extra 25mcg tablets? Heard from another patient they found a particular brand to cause these symptoms. Wondering if I could try getting my 75mcg daily dose by cutting my original 50mcg tablets and having 1.5 daily. Is there any truth in this theory?

Written by
samimanf83 profile image
samimanf83
To view profiles and participate in discussions please or .
Read more about...
6 Replies
Clutter profile image
Clutter

Welcome to the forum, SamimanF83.

It's not a myth, different makes can cause adverse effects. I found palpitations intolerable on Mercury Pharma and less so on Actavis. Wockhardt 25mcg were no problem for me.

Try your previous make 1.5 tablets. If symptoms improve your GP can prescribe [make] 50mcg x 1.5 tablets daily.

samimanf83 profile image
samimanf83 in reply toClutter

Thanks, ill definitely give it a try, these palpitations (tho harmless) are not nice 😕

Clutter profile image
Clutter in reply tosamimanf83

Samiman, Tell me about it. It felt as if the bed was bouncing with the violence of palpitations at times.

Both over and under medication can cause palpitations and increase ectopic beats. You should have a thyroid test 6-8 weeks after dose was increased to 75mcg to check levels. Leave 24 hours between last dose and blood draw which should be a fasting test (water only) and early in the morning when TSH is highest.

samimanf83 profile image
samimanf83 in reply toClutter

Didn't know that about the blood test prep...mine has always been tested randomly! It has always been within range since the increase to 75mcg...had a few tests since Dec cause I'm getting fertility investigations as well since they found PCOS at same time as hypo...just dropping to bits since turning 30 lol!

Sam x

Clutter profile image
Clutter in reply tosamimanf83

Sam, everything starts going south after puberty ;)

Being in range is not the same as optimal. Always ask for the results and ranges to see for yourself.

NICE recommend the TSH of women planning conception and newly pregnant should be in the low-normal range 0.4-2.0 with FT4 in the upper quarant of range. Levothyroxine is usually increased by 25-50mcg as soon as pregnancy is confirmed.

cks.nice.org.uk/hypothyroid...

samimanf83 profile image
samimanf83 in reply toClutter

Something to look forward to...

Not what you're looking for?

You may also like...

lower levothyroxine

I had a blood test done in October 2023 it came back with my TSH at 0.01 (range 0.27-4.2) and my T4...
Loopyloo243 profile image

On 50mcg Levothyroxine, suffering from insomnia and racing heart!

Hello all. This is my first post but I've been reading your posts for the last 4 months since...

Racing heart question

Tsh 7.8 so am told not really a problem but am on 35mcg dosage for 2wks until I'm supposed to up...
edde profile image

Dosage of Liothyronine and Levothyroxine

Post RAI have been on 75mcg Levo. Had DIO 2 test and am heterozygous. Have been on T3 for a week....
Mugs19 profile image

Levothyroxine Tablets

Hi Everyone Just a quick question, my GP has reduced my Levothyroxine dose to 75mcg a day. I have...

Moderation team

See all
Jaydee1507 profile image
Jaydee1507Administrator
PurpleNails profile image
PurpleNailsAdministrator
SlowDragon profile image
SlowDragonAdministrator

Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.

Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.