Erfa to Liothyronine Thybon Henning Dose Conversion

[hormonaljunkie]

Hello,

I used to take ERFA and levothyroxine but as my T3 was slightly high, my new Dr has put me on Thybon Henning so it will be a bit easier to manage T3 and T4 dosing (it's difficult to cut down on NDT as if I lower it I'm also lowering my total T4 dose, and I run low in T4).

I have a feeling he has given me a dose that is quite a bit lower than what I used to take in NDT, yet I don't want to swing on the other end and end up with low T3.

I've tried to find a conversion somewhere, and I know how to translate thyroxine mg into NDT grains, but I cannot find anything to convert the T3 grains to pure T3.

Would appreciate if anyone can help!

[helvella Administrator Thyroid UK]

I'm afraid, I am a touch confused as to what you are asking! I'll plough ahead trying to make a coherent reply but don't hesitate to tell me if I am not providing what you want to know.

Erfa contains the following in terms of T4 and T3:

60 milligrams (one grain) contains 35 micrograms of T4 and 8 micrograms of T3

(Note: Micrograms not milligrams.)

Thybon Henning comes in 20 microgram tablets. Therefore, one of those tablets has two and a half times as much T3 as one grain of Erfa thyroid.

You have not told us how much Erfa you have been taking, nor how much T4 and T3 you will be taking.

And most members who have switched between desiccated thyroid and T4 and T3 - or the other way round - find that this simple arithmetic conversion doesn't work. It might provide a rough guide but not to the exact microgram.

People differ in their absorption of T4 and T3 from desiccated thyroid as compared with T4 and T3 tablets. Both how completely and how quickly they are absorbed.

helvella's medicines documents (UK and Rest of the World) can be found here:

helvella - Thyroid Hormone Medicines

helvella has created, and tries to maintain, documents containing details of all thyroid hormone medicines in the UK and, in less detail, many others around the world. There is now a specific desiccated thyroid document.

This link takes you to a page which has direct links to the documents from Dropbox and QR codes to make it easy to access from phones.

The UK document contains up-to-date versions of the Summary Matrixes for levothyroxine tablets, oral solutions and also liothyronine available in the UK. Latest updates include all declared ingredients for all UK products.

helvella.blogspot.com/p/hel...