Thanks Helvella, this is interesting reading.
This report at the very least shows that there are concerns and that I am not alone in experiencing difficulties in changing brands (although this report is on levo and not Lio which I had the problem with, but I want to keep both of them on one brand to avoid any future problems).
And these statements:
" ...certain hypothyroid patients who are sensitive to
minor fluctuations (either increases or decreases) in their thyroxine levels. For these groups of patients, the content of levothyroxine in the tablet (assay or potency) and bioequivalence (or interchangeability) is extremely important."
"Currently licensed levothyroxine products in the UK were approved many years ago, under
previous legislative requirements. Consequently, these products, which are used interchangeably, are not supported by clinical data such as bioequivalence as expected by today’s standards."
"reports of adverse reactions associated with
changes in TSH values were further analysed. Of these, 177 reports (88.9%) were associated with a change to a different make of levothyroxine tablet"
also reports of formulation-related variability, where differences between the non-active ingredients (excipients) in different tablet products can cause changes in therapeutic response."
Make me wonder how they came to the conclusion that maintaining consistency in brands wasn't necessary. They don't necessarily know if different brands have the same Levo bio-availability. Their conclusion seems to have been reached by saying, 'well it's been done for years so it's okay'. Thing is it's not okay for everyone and the Dr's/Health boards often don't listen. It would have been good if they had added that although it might not be 'necessary' to keep to one brand, it should be supported if a patient requires it.
Do you happen to know if the 'recommended review of Liothyronine products' materialised?