how long for levels to adjust before blood test - Ndt user

[Bellsonit]

hi I was wondering if I could get some advice.

I use Ndt on top of thyroxine because it works better for me but gp won’t prescribe it and I’m no longer under my consultant. Taking the dose the consultant prescribed but because I can’t guarantee supply of Ndt now I’m sourcing myself I worry that if I have bloods it will be skewed and gp will change my prescription so wanted to revert to gp dose for bloods then go back to consultant dose with Ndt.

I’m Hashimoto so my tsh is always slightly supressed irrespective of what happens to my thyroxine and consultant put me on lower thyroxine but supplemented with Ndt which marginally improved tsh and massively improved t3 levels so will continue work Ndt as long as I can get it but worry gp will change things

My dose of thyroxine is 150mcg but with Ndt I am on 1 grain Ndt and 75mcg thyroxine

[greygoose]

I’m Hashimoto so my tsh is always slightly supressed irrespective of what happens to my thyroxine

I really don't think Hashi's has that effect on TSH. It's more likely to be a slight problem with your pituitary if your TSH doesn't rise properly.

how long for levels to adjust before blood test

Which level are you talking about? TSH can take weeks to adjust. FT4, depends how much you're taking and where you want it to be. FT3 drops faster but again, depends on the same variables as the FT4. So, not sure anyone can answer that question with any certitude. But, T4 has a half-life of about 7 days, and T3 about 24 hours. So, maybe you can work it out, roughly.

[tattybogle]

GP will only be interested in TSH and possibly fT4... they won't know what your fT3 level is unless they test it which is highly unlikely (or unless you tell them).

You said TSH was marginally improved on NDT+75mcg Levo...so assuming you mean it's marginally higher than it was on 150mcg Levo then you GP has no reason to know you've added NDT/ reduced levo unless you tell them , and will be happier as TSH is now higher .

you'd have to go back on levo only for several weeks before a blood test to allow your TSH enough time to change , because TSH can take ages to move in response to changes in T4/T3 levels . meaning you'll likely feel off for a couple of months as a result of going back to levo only just for a blood test.

and if your TSH is slightly higher on NDT+75Levo there's no point going back on just levo as a lower TSH will make it more likely they are to want to reduce you levo dose .

if you only take 75mcg and you are prescribed 150mcg then even if they do insist on reducing prescription a bit , it doesn't matter , as long as they prescribe 75mcg .

[Bellsonit in reply to tattybogle]

thanks to you and greygoose you’ve both made some really valid points here that if my tsh is marginally less suppressed on Ndt then in theory they shouldn’t change the dose. My worry of them reducing my dose is if I for some reason can’t get Ndt then the dose will be really low for me and I’ll have to battle with them to get it back up again.

Yeah my tsh just doesn’t seem to move at all - and that’s what they bang the drum on. Fortunately they test my t4 too