Question

[Steni]

I’m wondering - is there a difference between Liothyronine Sodium and Liothyronine Hydrochloride? The first is what I was prescribed in my NHS trial and the other is how my new Thybon Hemings is described.

[helvella Administrator Thyroid UK]

Yes and no!

The liothyronine in the one case has a sodium atom attached whereas in the other it has a hydrochloride radical.

Does it make any difference? Probably very little, if any.

Once liothyronine has mixed with stomach acid (hydrochloric acid), it likely ends up in exactly the same form regardless whether it started off as the sodium salt or the hydrochloride form.

Many people have switched between Thybon Henning and other liothyronine products without being able to identify a significant difference. A very small number have attributed their getting on less well with Thybon Henning to the fact it is the hydrochloride form but I don't think we can be sure of that.

[Steni in reply to helvella]

Thank you 👏

[MaisieGray in reply to helvella]

I would add that when I was searching for an answer to the same question, I came across some research into another drug - the name of which I've since forgotten of course - which was likewise available in +sodium and +hydrochloride salt form. The findings were that the one form had four times the effect of the other. Without implying any similarity or direct comparison with a random other drug of course, is it not therefore at all possible in principle, that the different liothyronine forms might likewise have differing degrees of effect?

[helvella Administrator Thyroid UK in reply to MaisieGray]

I think diogenes has previously answered this question for liothyronine.

Must admit, I would be surprised for most medicines if the sodium versus hydrochloride forms were massively different - assuming ordinary oral tablets. It would be good if you did remember what it was that was so dramatically different.

[MaisieGray in reply to helvella]

Ah, has he? I'll do a search for that then. The study was looking at control of seizures, so clearly no connection whatsoever, with T3, but I was struck by the degree of difference between the two forms. However, I left my chemistry studies behind a very long time ago, so can make no useful inference about the results. I will try and remember the actual drug/study.

[jimh111]

I haven't found a difference between the two although I find Thybon superior in that it keeps its potency. AMCo / Concordia comes in tubs and I find the tablets become less effective a week or two after a tub has been opened. Once it gets into the bloodstream it is pure liothyronine (L-T3).

[SlowDragon Administrator in reply to jimh111]

Would certainly agree that Mercury Pharma T3 by Concordia looses its potency once pot is opened

Morningside Healthcare T3 is blister packed and longer use by date as well