Is it possible to build up a tolerance to liothyronine?

[JonnyA]

I’ve found myself in the midst of an interesting, if somewhat unpleasant accidental experiment these last few days. Having had some issues in obtaining my usual supply of Thybon Henning, I’ve now gone 9 days without medication. This was very much unintentional, and I am aware is not medically advisable.

I’ve been taking liothyronine now for just over 2 years, and it did occur to me recently that I hadn’t felt quite as good as I did in the first 12 months or so of taking it.

This has been an eye opener however, and I can remember just how bad I used to feel prior to treatment. The crippling fatigue, the broken, shaky voice, the sensitivity to cold, the constipation and, oh, and the bradycardia - the old resting heart rate of about 35 is back. I had forgotten about that one, but it’s an interesting barometer all the same and confirmation that the apparent return of symptoms isn’t merely psychosomatic.

Going back a step though, as mentioned, I hadn’t felt quite as good lately even on my usual dose of liothyronine, albeit I now realise a thousand times than I feel right this moment.

But it did raise a question in my mind, well, two:

1. Is there any possibility that in two years of taking liothyronine my body has built up a modest degree of tolerance to it, hence a modest reduction in its effectiveness?

2. IF it is possible, would this unintended, brief cessation in taking it have done anything to “reset” or “normalise” my body’s sensitivity to it?

Apologies for any ignorance in the above questioning; I’m not as well read on the subject in recent times as I have well for the most part.

Thanks!

[greygoose]

Is there any possibility that i :)n two years of taking liothyronine my body has built up a modest degree of tolerance to it, hence a modest reduction in its effectiveness?

No. T3 is a hormone, not a drug. Hormones don't behave like that.

It''s more likely that you were in need of a small increase in dose. Our needs change, so I expect it was that.

[janeroar]

Good to get your blood levels checked so you can see where you are. I ageee with greygoose you were probably needing more that’s why you were feeling a dipping.

[radd]

JonnyA

1. Is there any possibility that in two years of taking liothyronine my body has built up a modest degree of tolerance to it, hence a modest reduction in its effectiveness?

It’s not ‘tolerance’ but receptors can become desensitised if they are consistently overloaded. You can also end up with excess binding proteins as the body tries to balance the right amount of ‘free’.

In this situation raising meds will worsen the resistance longterm. The difficulty is in establishing if the excess is genuine or other factors have diminished T3 effectiveness.

2. IF it is possible, would this unintended, brief cessation in taking it have done anything to “reset” or “normalise” my body’s sensitivity to it?

Unlikely with cessation of T3 meds as the shock would be enormous and have heightened stress hormones. However, members have often reported a short lived improvement after stopping dysfunctioning Levothyroxine meds because the feed to RT3 is reduced.