The treacherous use of thyroxine preparations

Endocrinologists not infrequently confront the problem of inconsistent blood values of thyroxine among patients receiving L-thyroxine preparations. The question is how universal this problem is. The treacherous use of thyroxine preparations. Stability of thyroxine preparations Demetrios A. Koutras, HORMONES 2003, 2(3):159-160 Before the use of L-thyroxine or thyroid gland preparations, hypothyroid patients were left untreated. It was therefore a landmark in the history of medicine when for the first time Murray in 1891 treated hypothyroidism with injections of an extract of sheep thyroid glands. ( 1 ) The preparations from animal thyroid glands were later standardized according to their iodine content, but nevertheless had a variable content of the active thyroid hormones L-thyroxine (T4) and L-triodothyronine (T3), and also had a relatively short ‘shelf-life’, i.e. their biologic potency decreased with time, especially if not properly stored. Hence, they were replaced in the sixt