Re: Thyroid replacement not perfect.

[Guest guest]

On this note:

from The Medical Letter 43:57-60(2001).

" Levothyroxine is an inherently unstable compound because it is markedly

affected by heat, light, air and humidity. In addition, it is marketed in

an unusually large number of dosage strengths formulated in small tablets

that require particular care in manufacturing practices to maintain

consistency. "

" Two NDAs for levothyroxine (Unithroid and Levoxyl) have been approved by

the FDA to date, and more approvals are expected. The FDA's threat to

withdraw Synthroid arose from the manufacturer's tardiness in submitting an

NDA. FDA approval means that any change in the formulation or the

manufacturing process must be cleared with the agency. In practice,

however, FDA quality-control requirements may be insufficient to detect some

clinically relevant changes in manufacturing conditions or in the

physiochemical characteristics of the drug. "

Anyhow, this illustrates the information from the article that Pam provided

and it was from a completely different source. That last sentence really

got me going.

Take care,

dx & RAI 1987 (at age 24)

> Offical document folks.

> MINI REVIEW: Intrinsic imperfections of endocrine replacement therapy

>

> J A Romijn, J W A Smit and S W J Lamberts

>

> Departments of Endocrinology, Leiden University Medical Center, Leiden and

> of Internal Medicine, Erasmus Medical Center, Rotterdam University,

> Rotterdam, The Netherlands

>

>

>

> (Correspondence should be addressed to J A Romijn)

>

>

>

>

>

>

>

> Abstract

>

> Hormonal substitution therapy has been extremely successful in the

treatment

> of the major syndromes of endocrine insufficiency with respect to

morbidity

> and mortality.

>

> However,

>

> many patients treated for endocrine insufficiencies still suffer from more

> or less vague complaints and a decreased quality of life. It is likely

that

> these complaints are, at least in part, caused by intrinsic imperfections

of

> hormone replacement strategies to mimic normal hormone secretion.

>

> Unfortunately, these complaints are often difficult to assess by

> clinicometric or biochemical tests, because the effects of hormones in

> general and, thus of hormone replacement strategies in particular, at the

> tissue level are difficult to quantify.

>

> Therefore, in clinical practice we rely mostly on plasma parameters

'plasma endocrinology', which are a poor reflection of hormone action at the

tissue level. Appreciation of these intrinsic shortcomings of endocrine

therapy is of utmost importance to prevent incorrect labeling of the

complaints of many endocrine patients and to further improve endocrine

replacement strategies.