Eltroxin in New Zealand - Many Lessons to be Learned
Rod
comments about the problems with Eltroxin there.
Announcement:
<http://www.medsafe.govt.nz/hot/media/2008/EltroxinSept2008.asp>
Detailed discussion:
<http://www.medsafe.govt.nz/downloads/eltroxin-media-conference-information.doc>
Below are some comments on what I have gleaned by reading these documents.
The potency required by NZ is in the range 90 to 110% of label claim.
The achieved range of the new tablets on independent testing was
91.9-100%. The old formulation achieved 97.7-100%. That represents
deterioration in potency at the bottom of the range of 5.8%. I'd suggest
that someone on a marginally adequate dose before the change could have
slipped much lower after the change. (There are absorption differences
to take into account as well.)
The potency requirement in UK and USA is 95 to 105%. The new NZ
formulation would not conform.
The levels of permitted impurities (%) required by NZ are:
Liothyronine sodium ≤ 1.0
Tetrac ≤ 1.0
HDPhDB ≤ 2.5
Any other impurity ≤ 1.0
Total ≤ 5.0
The implication is that a 100mcg levothyroxine tablet can contain up to
1mcg of Liothyronine (T3). I have seen the effects of 2.5mcg T3 – and
they are significant.
We hear that T3 is four times as potent as T4. In our bodies, T4:T3
conversion takes place alongside T4:rT3 and other processes. In tablets,
however, the ‘conversion’ could run much closer to 100%. So a 100mcg
tablet could degrade to 99mcg T4 plus 1mcg of T3, or 95mcg T4 and 5mcg
T3. This would have the effect of increasing effective potency. Or is
the degradation even less than what our bodies achieve?
[I wonder what all the anti-T3 endocrinologists would make of the fact
that levothyroxine can be significantly contaminated by T3?]
Tetrac (Tetraiodothyroacetic acid) is biologically potent. One reported
effect is blocking angiogenesis induced by vascular endothelial growth
factor and basic fibroblast growth factor.
I do not know what HDPhDB is.
A total of 5% impurities seems to be quite high.
This is the first time I have seen this type of analysis of a real
product (rather than vague, anonymous research lab results).
--
Rod
Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
<www.thyromind.info> <www.thyroiduk.org> <www.altsupportthyroid.org>
Rod
I couldn't help but laugh/snigger/snort as I read that they tested
patients for 48 hours. Surely all medics (and related) know that thyroid
hormone changes can't possibly be noticed for at least four weeks!!!!!!
================
Blue: Explanation Wanted As To Why Alarm Bells Didn't Ring Over Eltroxin
Results
15 September 2008 - National's Associate Health spokeswoman, Jackie
Blue, says there were obvious clues that there could well be problems
with the new formulation of Eltroxin.
She is commenting on a response to a parliamentary written question
which provided results of bioequivalence tests performed on the new
formulation.
"The 36 test subjects in the study were randomly assigned either the new
formulation Eltroxin or the standard preparation, and monitored for 48
hours over which time blood levels were taken and adverse events recorded.
"After the drug left their system they received the opposite drug and
were followed for another 48 hours.
"Almost 25% of the subjects experienced an adverse event when taking the
new formulation of Eltroxin, compared to just 8% taking the standard
formulation.
"I'm not an expert in these sorts of tests but the fact that nearly
three times as many people had problems with the new formulation would
have raised my eyebrows.
"The authorities need to explain why this information did not ring alarm
bells for them.
"If this had been flagged earlier we might have avoided the debacle that
has seen more than 800 adverse effects reported to the Centre for
Adverse Reactions Monitoring."
Herman Family
"Rod" <poly...@ntlworld.com> wrote in message
news:6j7209F...@mid.individual.net...
If adverse effects are showing up in 25% of patients within
48 hours, we can make a wild guess that it will be 50%
within another few, and nearly 100% within a month. That's
pretty bad.
The longer durations (weeks to months) of testing would work
for efficacy and long term tolerances. This was just a
quick safety check.
What is disconcerting is that the adverse effects were not
named or quantified.
Michael