Thyroid UK
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Quick synthroid question

Does anyone know if your weight determines the dose of synthyroid your put on and where would I find this info ? I ask only because I was place on 112mcg after my thyroidectomy and Im not sure how they determined this dose I thought endo said based on my weight but I really disliked my first endo so much I glazed over when ever he opened his trapped. Yes this endo still makes me cringe.

Thanks

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Batty1,

It used to be that a dose to weight ratio was used post thyroidectomy but I'm not sure how commonly it is used now. Certainly wasn't in my case. My oncologist totally over replaced me.

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Vets dose by weight....

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Vets?

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Spareribs But also a sighthound gets less thyroxine than a lab because they have less body fat and lower thyroid hormones as a norm

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Hi Barry 1 how are you my amount was given to me because my thyroid stopped working altogether I'm on 100mg through the week and 150mg weekend I don't think it has anything to do with your weight I take eutroxsig I hope that helped

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Oops sorry I meant Batty1

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Hahahaha spareribs

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I was dosed by weight after TT nearly 2 yrs ago

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Guys reduced my dose because they said I had lost weight I had atropic AT but my thyroid had effectively died according to scans so probably made nothing. What they failed to take into account was that I had put on nearly 4 stone so my normal weight had nowhere near been reachieved. Seemed a nonsense to me I asked them if it was by weight how come my sister was on 175mcg who was tiny but I was on 100mcg and was a much bigger build. They just flanneled. She had lymphoma of thyroid and TT so it was probably a suppressive dose. I felt better on 125 and pretty crazy on anything higher but still rubbish even when less hefty. I switched to NDT plus went gluten free and the weight just fell off. Weight is such a variable - seems to me how you feel is the best indicator of the dose you need. As a rough guide ok but there are more meaningful measures of good health surely.

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Batty1,

There are several ways of estimating the levothyroxine requirement post-thyroidectomy based largely on weight.

I took some published formulas and created a spreadsheet. This is for interest and should not be used for dosing:

dropbox.com/s/779n1uycxtujx...

The whole idea of dose by weight is ill-conceived beyond this one use for estimating. We are all different. The other day diogenes posted a paper which showed that our set-points vary inherently. And which weight is rarely defined - lean body mass? actual scale weight? It is all a fancy way of guessing.

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Cant open your drop box

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Send me your email by private message and I will send you a copy.

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Being a logical type of person I thought that it could be that people would be dosed after a TT by weight but this does not work.

I asked the same question after my TT in 2015. Some people on medication have lots of other issues as well. Some have hasimotos some have gut problems, high blood pressure the list goes on and on.

It just takes time and patience also the brilliant help that you can receive on this site.

I have now after two years started to feel much like my old self because the great help that I have received.

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I know as I lost weight, my dosage of synthroid was decreased from 112 to 100, but my Cytomel dose stays the same

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Thanks for all the great replys even spareribs who seems to be woofing it up 😋 I did find a great calculator for synthroid dose from another site. Can anyone tell me how to add it to my post?

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I'd be interested to know what it does that my speadsheet doesn't do, if you could let me know?

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Hi

All my friends here were placed on 200 mg if only taking thyroxine- I’ve asked my specialist this who said why would you only take t4? She’s in favour of ndt slow and steady. Monitoring your results and vitamins obviously.

Weight is fine if you don’t have an absorbtion issue which many people have.

Best wishes

Helena

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It's: your weight in Kgs *1.7 = your dose of Levo in mcgs. However, this should be used as a first approximation, you will have to fiddle around for many months to get the exact dose that is right for you. Secondly, you should be on T3 only after a TT. They do this to prevent any thyroid cells left from growing back. If the Levo they put you on isn't high enough then any remaining thyroid cells will respond and try to produce T4 - and you don't want that.

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P.S.

Multiply your stones by 14 to get lbs.

Multiply those lbs by 2.2 to get kg

Then apply the formula Kgs*1.7 = dose (well, first approx)

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