Some History of Thyroid Drugs and Thyroid Treatment
I cut this information from part of a previous blog as I thought it would be useful when referring to the history of thyroid treatment.
The history of thyroid treatment is interesting as it makes it so clear why we are in the mess that we currently are in with lab test driven treatment, and no T3 being prescribed when it is required
Some History Prior to the 1970s
Synthetic T4 (Synthroid, Levothyroxine) was first introduced in the 1950s. Current thyroid lab tests (TSH, and the other thyroid labs) were invented in the 1970s.
Before these events, all doctors had available was good clinical judgement, based on the symptoms and signs (body temperature etc. and possibly basal metabolic rate), of the patient, and the option to use natural desiccated thyroid (NDT). NDT contains both T4 and T3 thyroid hormones! It is a natural way to replace thyroid hormones, as we make both T4 and T3 within the thyroid. A healthy thyroid gland converts a significant amount of T4 to T3. So, replacing missing thyroid hormones made sense to do with a mixture of T4 and T3 hormones in the form of NDT at the time.
When doctors worked with a patient, they would assess many things and try to reach a judgement over whether the patient might have a thyroid problem or not. If low thyroid hormones were suspected, a trial of NDT would be started. If there were improvements in symptoms and signs, the NDT would be adjusted (titrated) to a higher or lower dose if needed. This titration process would continue based on the presenting symptoms and signs of the patient. This meant that the doctor would have to work with the patient and listen to what they were saying about how they were feeling in response to treatment. There were no laboratory tests to get in the way between the doctor and the patient in front of them.
This approach worked pretty well a lot of the time. It ought to have moved forward from there, taking advantage of modern lab testing (but not being a slave to it), and having all the other thyroid medications available.
What Happened from the 1970s Onwards
In the 1970s the TSH test became the standard way to assess whether thyroid treatment was working. Levothyroxine/Synthroid/T4 became the standard medication for treatment. Both of these required almost no effort on the part of the doctor or endocrinologist compared to what happened in the past. It vastly reduced the work of the physician. The reliance on the TSH test and the use of T4 medication also virtually guaranteed that no patient would ever be over-medicated.
This sea-change was the beginning of conveyor-belt thyroid treatment, optimised for the doctor and far less likely to result in over-medication of the patient. It was much more likely to result in the under-medication of the patient!
Unfortunately, it is a method that usually results in improperly treated hypothyroidism. It is a broken paradigm.
Why is this a broken paradigm? I have written about this in many other blog posts, but here is a resume based on recent research:
TSH can be totally suppressed when on thyroid treatment, i.e. near zero. This is fine and it does not mean the patient is hyperthyroid. So, keeping someone to an in-range TSH may leave them under-medicated.
TSH does not track symptom improvement. So, a doctor cannot see a change in T4 medication and a lowering of TSH and assume that the patient is doing better.
FT4 does not track symptom improvement either. A higher level of FT4 does not mean that the patient will be feeling better.
FT3 does track symptom improvement but this is not the meaure that most doctors focus on.
The reference ranges for FT4 and FT3 are population ranges - they are far too wide to conclude anything about whether a patient is well-treated or not.
Real individual reference ranges (which cannot be known before treatment) are less than half as wide as the wide population ranges for FT4 and FT3.
rT3 may or may not be an issue, and for sure there is no ideal FT3/rT3 ratio for all patients. Just as the lab ranges are wide population ranges, people all have their own individual requirements for their labs. No ratio or reference range can be applied to all people. Very high rT3 is usually an issue but that's about all you can say about it in isolation - symptoms and signs of the patient say more.
T4 does not work for all patients. Some patients cannot get well using T4 medication.
Research has shown that the loss of conversion capability and of the thyroid gland in thyroidectomy patients, causes the loss of the abiity to achieve a balance of thyroid hormones and good conversion rate (homeostatic balance).
We also know that the thyroid gland itself is responsible for around 25% of our T3, mostly through conversion, so tissue damage through Hashimoto's, or through removal of the thyroid, loses a huge amount of ability to convert from T4 to T3. This can often not be compensated for with T4 alone.
We also know from research that some people have genetic defects that reduce the capability to convert from T4 to T3 (DIO1 and DIO2 gene defects).
- We also know from an immense body of thyroid patients that many of them need different medications to get well: T4, NDT, T4/T3, or in some cases T3-Only.
So, the current paradigm of thyroid treatment is broken, and the research has shown this.
The Consequences of the Broken Paradigm
This is the really sad aspect of all of this.
Thyroid patients are being left improperly treated in many, many cases. They are either on the wrong medication for them, or they are being left under-medicated.
I have written a fuller version of this in this blog post: http://recoveringwitht3.com/blog/chasing-ideal-lab-test-results-road-nowhere
Patients actually got better treatment prior to the invention of Levothyroxine/Synthroid and the new lab tests.
The diagnosis and treatment ought to have got better!