VanessaB No, he's wrong, he belongs in the same pile as the other idiot doctors who are TSH obsessed, blinkered, have their heads in the sand, and refuse to look at the whole picture.
Once on Levo TSH is irrelevant because it is a pituitary hormone. Basically, the pituitary looks to see if the thyroid is producing thyroid hormone. If not it sends a signal to tell it to - TSH (Thyroid Stimulating Hormone). If you're not producing much (as in hypothyroidism) the TSH will be high. If you are producing plenty the TSH will be low. But the TSH will also be low if you provide that thyroid hormone synthetically (Levo). So your pituitary has recognised that you have some thyroid hormone because you are taking Levo so it doesn't send the signal (TSH) so TSH is low.
Blimey, reading that back it sounds gobbledegook. I'm sure there's a simpler way of explaining it but I'm having a foggy brain day today!!!
When you were on 175mcg Levo and results were
Ft4: 14 (9-19)
Ft3: 4.6 (3-5.6)
he reduced your Levo due to the TSH being low, but your FT4 and FT3 are only about half way through their reference ranges so not particularly brilliant.
On 150mcg Levo and results now
Ft4: 9 (9-19)
then there's not much difference in your TSH but look what it's done to your FT4, it's right at the bottom of the range, and your FT3 will have lowered as well.
What does he think will happen with a further reduction in Levo? Your FT4 will drop below the reference range, as will your FT3, and you will feel as bad as when you were first diagnosed.
From ThyroidUK's main website > About the Thyroid > Hypothyroidism > Treatment Options:
"According to the BMA's booklet, "Understanding Thyroid Disorders", many people do not feel well unless their levels are at the bottom of the TSH range or below and at the top of the FT4 range or a little above."
You can buy that book from Amazon for about £4.95 and show tha the relevant part to your GP.
"Dr Toft states in Pulse Magazine, "The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.
In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance.
But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.
This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."
Dr Toft is past president of The British Thyroid Association and leading endocrinologist. You can obtain a copy of the article by emailing firstname.lastname@example.org , print it off, highlight question 6 and show your GP.
If it doesn't make him increase your Levo then you have to fight your corner. Tell him that you have taken advice from NHS Choices recommended source of information for thyroid disorders, which is ThyroidUK, and if he won't increase your Levo then you would like a referral to an endocrinologist. Before you make any appointment with an endo, email Louise (as above) for the list of thyroid friendly endos and whoever is in your area then ask for feedback from forum members, there's no point in seeing one who is as TSH obsessed as your GP.
The alternative is, of course, to self medicate and do private thyroid tests.