woensdag 26 november 2014

Thyroxine stability and formulation: why the secrecy?

Dit bericht gaat over een ingezonden brief in de Australian Prescriber uit 2005. De schrijver van de brief is endocrinoloog en hij verbaast zich over de geheimzinnigheid rond de stabiliteit en samenstelling van levothyroxine. We zijn 10 jaar verder en eigenlijk is er niets veranderd. Of het nu gaat over het preferentiebeleid, leveringsproblemen, verandering van verpakking of producent en productielocatie.

Thyroxine stability and formulation: why the secrecy?
Jim Stockigt, Australian Prescriber

Clinical strategies in the testing of thyroid function
Jim Stockigt, Thyroid Manager

Editor, – In May 2004 Australian pharmacists were instructed that thyroxine tablets should be stored refrigerated, before and after dispensing. This uniquely Australian directive, which carried the imprimatur of Sigma, the sole supplier of thyroxine tablets in Australia, and the Therapeutic Goods Administration, appears to have been ill-considered. (1) Dampness should be avoided during storage of thyroxine (2); repeated daily opening of a refrigerated glass bottle over many months can make the tablets damp, with loss of potency. (1) Sigma has now conceded that tablets in current use from unsealed bottles should not be refrigerated (1), although pharmacists generally are unaware of this change.

In letters to doctors and pharmacists during 2005, Sigma foreshadowed a change in formulation so that thyroxine tablets will be presented in five bottles of 40 tablets, with a recommendation to refrigerate the unopened bottles, but not the bottle in current use. In support of this change, Sigma refers to ‘new stability data’. However, Sigma has refused to present these data for professional scrutiny, except under terms of a confidentiality agreement that precludes discussion or peer review.

The reasons for seeking public disclosure of these ‘new stability data’ have been set out in detail. The health of about 200 000 Australians depends on thyroid hormone replacement. They, and those who accept responsibility for prescribing this medication, have a right to know the details of the sole preparation that is available. If storage temperature is a key factor in maximising the tenuous shelf-life of thyroxine, our local data might be important in addressing the broader problems of stability, potency and bioavailability of thyroxine. (3, 4)

If we cannot achieve a culture of open disclosure between the pharmaceutical industry and consumers for a medication as straightforward as thyroxine, what chance do we have with medications that are shrouded in commercial confidentiality, contentious trial data, patent law and unexpected or contentious adverse effects? Do we really care whether there is an ethos of evidence-based medicine in the manufacturing, regulatory and dispensing arms of pharmaceutical practice? If so, the ‘new stability data’ should be made known. Only in that way can consumers establish whether the modified formulation is necessary, or whether it is being introduced as a face-saving initiative.

References

  1. Stockigt JR, Should thyroxine tablets be refrigerated? Have we got it wrong in Australia?, (with reply by Siddiqui O, Sigma Pharmaceuticals). Med J Aust 2005;182:650.
  2. Roberts GW, Taking care of thyroxine, Aust Prescr 2004;27:75-6.
  3. American Association of Clinical Endocrinologists (AACE), The Endocrine Society (TES) and American Thyroid Association (ATA), Joint position statement on the use and interchangeability of thyroxine products, American Thyroid Association; 2004.
  4. Stockigt J, Testing the bioavailability of oral L-thyroxine by studying its absorption: smoke or mirrors?, Thyroid 2004;14:167-8.








5 opmerkingen:

Utrechtse zei

Goede vondst! Zo zie je maar weer, wat we zonder het schildkliertje niet te weten komen.

De houdbaarheid van medicijnen kan door een aantal factoren worden beinvloed, zoals warmte, water, licht en zuurstof. Het artikel "Houdbaarheid van geneesmiddelen" gaat hierover:

http://gebu.artsennet.nl/Archief/Tijdschriftartikel/Houdbaarheid-van-geneesmiddelen-1.htm

Laura zei

Dank je wel ;-)

Anoniem zei

Inderdaad is het gissen naar de redenen achter die geheimzinnigheid. Wat mij bevreemdt is dat de gezondheidsautoriteiten die gewoon laten voortbestaan, terwijl er wel heel strenge regels zijn voor de toelating van geneesmiddelen. Ik vraag me af waarom die niet worden ingezet.

Utrechtse zei

De link die ik destijds plaatste doet het niet meer, dus even opgezocht in het internet archief: http://is.gd/20LouT

Laura zei

Dank je wel voor de update!

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