A Review of the Pharmacokinetics of Levothyroxine for the Treatment of Hypothyroidism.

@article{Colucci2013ARO,
  title={A Review of the Pharmacokinetics of Levothyroxine for the Treatment of Hypothyroidism.},
  author={Philippe Colucci and Corinne Seng Yue and Murray P. Ducharme and Salvatore Benvenga},
  journal={European endocrinology},
  year={2013},
  volume={9 1},
  pages={
          40-47
        }
}
Thyroxine hormone has been recognised since the early part of the nineteenth century and levothyroxine has been available since the mid-nineteenth century as a replacement for deficient thyroid hormones. While levothyroxine remains the staple treatment for hypothyroidism even to this day, its optimal use can be challenging. As is often the case with older drugs, the pharmacokinetics of levothyroxine is often under-appreciated or misunderstood and many factors influence the optimal dosing of… 
Levothyroxine Administration Timing in Hypothyroidism Patients
Levothyroxine is a synthetic T4 hormone that is biochemically and physiologically identical to the natural hormone, and it is used when the body is deficient in the natural hormone. This study was
When thyroid hormone replacement is ineffective?
  • S. Benvenga
  • Medicine
    Current opinion in endocrinology, diabetes, and obesity
  • 2013
TLDR
The failure of thyroid hormone replacement therapy to normalize serum thyroid stimulating hormone concentrations is considered and reasons for ineffectiveness are noncompliance, inappropriate administration of levothyroxine, gastrointestinal disorders, and drug interactions.
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TLDR
A number of randomized, controlled trials have failed to demonstrate superiority for the combination therapy approach, largely due to non-physiological T3 doses, but patients with hypothyroidism are highly heterogeneous in terms of their residual thyroid function, individual set points for optimal thyroid homeostasis and for the presence or absence of polymorphisms in deiodinase enzymes.
Increased Requirement of Replacement Doses of Levothyroxine Caused by Liver Cirrhosis
TLDR
Increased requirement of daily doses of l-thyroxine in two patients with the atrophic variant of Hashimoto’s thyroiditis and liver cirrhosis is reported, with a similar increased requirement of L-T4 observed in other situations characterized by elevation of serum TBG.
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TLDR
A decision tree is developed for the physician faced with an abnormally high thyroid-stimulating hormone (TSH) level in a patient reporting adequate compliance with the recommended LT4 dose, and an in-depth etiological investigation can reveal visceral disorders and, especially, digestive tract disorders.
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TLDR
The results proved that l-T4 ingestion in the morning and at bedtime are equally effective, and also that the co-administration of l- T4 with food depends on the drug formulation, and that maintaining a proper time interval between food intake provides another effective method of eliminating such interactions.
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TLDR
A concise, narrative review of the clinical research and evidence-based guidance on the management of hypothyroidism is presented, finding that systematic and thorough investigation of the potential causes of persistent symptoms while receiving LT4 therapy will resolve the problem for most patients.
Patients with lactose intolerance absorb liquid levothyroxine better than tablet levothyroxine
TLDR
In 5 patients with LI with an increase in serum thyrotropin [thyroid stimulating hormone (TSH)] levels, that was reversibly resolved by switching to the same dose in a ‘liquid (Tirosint vial, IBSA Farmaceutici Italia) oral formulation (lactose-free)’ (L-T4-Liq).
Is levothyroxine requirement the same for tablet and soft gel formulations?
TLDR
The aim of the study was to investigate whether the LT4 requirement to achieve normal TSH values differs between the tablets or soft gel capsules formulations.
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TLDR
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