over prescribed levothyroxine

[carolbobs]

I have been on 100mg of levothyroxine for over 20 yrs. I recently had a pre op test and my tsh was less the 0.1 and my free t4 37.2 the hospital cancelled my op and i went to see my dr. he told me to stop the levothyroxine and will test again in 4 weeks but after 5 days i can feel a difference. is 4 weeks too long and when would a normal test show as im desperate to resume my place for the operation. `my previous test was almost 2 yrs ago

thanks

[helvella Administrator]

I think that if you stop for a full four weeks, you will become severely hypothyroid.

You are in a bind. On the one hand, a few days without then resuming at a lower dose might be sufficient. On the other hand, it really can take six weeks for blood test results to stabilise after a significant change of dose. An earlier test might indicate the direction of change perfectly well. But it could still change further. TSH in particular can take a longer time to stabilise.

Levothyroxine (T4) has a half-life of around 7 days. If you are not taking any more levothyroxine, your blood T4 level will drop substantially in a week. However, I suspect you still have some thyroid function and that makes it very difficult to estimate what will happen.

Are you in a position to order a private blood test? If so, you could do that and see what comes back. However, you shouldn't have to do that just in order not to suffer hypothyroidism.

Is it possible the surgeon or anaesthetist would be willing to re-test even if your GP isn't?

[carolbobs in reply to helvella]

thanks for your reply, my hospital is an hour and half away i dont know if they would re test, the dr has said 4 weeks because it fits nicely in with his holiday!! ive ordered a test online from medichecks and i recieved it the next day so im going to do it next thursday and then go back to see a differant doctor depending on the results. i dont know how much thyroid function i have as I've been on the 100mg for a long time. I can feel the differance already the shakes are less and the palpatations are getting better.

[helvella Administrator in reply to carolbobs]

the dr has said 4 weeks because it fits nicely in with his holiday!!

Nothing to do with patient well-being and biochemistry, then?

Take care. Some people, in some circumstances, seem to be able to tell quite well whether they are near-optimum or miles off. Others can be way under- or over-dosed and not have the slightest idea. Being aware sometimes focuses attention.

[sandysnow in reply to helvella]

I agree and it is the bind I find myself in. These blood tests are very expensive and I am now thinking of going back to levothyroxine as I think I may be over and my doctor (new) is playing havoc with me. I hate big pharma.

[carolbobs in reply to helvella]

So update on this, they stopped my 100mg thyroxine in february that ive been on over 20yrs because of the opertation being cancelled. 6 weeks later the level had dropped from 37.2 to 22.2 (ft4) So thank goodnes and my op went ahead, now 3 weeks later it has dropped to 17.2 Free T4 - i asked the dr how much hes going to let it drop before he introduces a lower dose his reply is ill test it every 4 weeks. by which time i think im going to be very ill now dont know what to do any ideas

[helvella Administrator in reply to carolbobs]

So pleased that you had your operation - hope that was successful.

It is very difficult to know what to suggest. That your FT4 is at 17.2 after three weeks without taking any certainly implies that your thyroid is producing thyroid hormone. But how far, and how quickly, will it drop?

Without being able to test and test and test again, I suggest that if you think you are slipping down too far, you go back and say so, firmly. Make notes of changes. Even take your temperature regularly.

[carolbobs in reply to helvella]

thank you for your reply, I told the dr on the phone last week that im tired and freezing cold all day and night, hes not bothered hes saving money and thats what it comes down to for them unfortunatly these days. Ive been advised from a friend to try contacting a private endocrinologist so ill keep you updated on that one. The op was a full knee replacement im doing great.