There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
The FDA Drug Labels for thyroxine (PO) do not address this question.
From the Research
Half-Life of Thyroxine (T4)
- The half-life of thyroxine (T4) is not explicitly stated in most of the provided studies.
- However, one study 1 mentions that the plasma half-life of D-thyroxine (DT4) is less than 1 day.
- Another study 2 mentions that synthetic levothyroxine (L-T4) has a long half-life, which allows for once-daily administration, but does not provide a specific value for the half-life of T4.
- A study 3 mentions that dose adjustment of levothyroxine should only be considered after 6 to 12 weeks, given the long half-life of levothyroxine, implying that the half-life of T4 is around 6-12 weeks, but this is not a direct measurement of the half-life.
- A study 4 mentions that the individual thyroxine half-life can be calculated after three weeks of treatment, but does not provide a specific value for the half-life of T4.
Related Information
- The half-life of triiodothyronine (T3) is mentioned in one study 2 as being short, requiring twice-daily administration.
- The half-life of D-thyroxine (DT4) is mentioned in one study 1 as being less than 1 day.
- The studies provide information on the treatment of hypothyroidism with levothyroxine, including the dosage, administration, and monitoring of the treatment, but do not provide a direct answer to the question of the half-life of T4.