PO T4 in ICU

Q: What is the caveat of prescribing oral thyroid replacement therapy in ICU patients who are on continuous tube feed?

Answer:  

Thyroid replacement (T4 or Thyroxine) in either of its forms like gel, capsule or tablet should be ideally taken on empty stomach. It becomes only of academic importance as many times it is impossible to time the thyroid replacement in ICU patients particularly those who are on continuous tube feeds. Although this may decrease some efficacy of thyroid replacement, it still provides sufficiently required clinical action. 

Another viable option is to provide thyroid replacement in an intravenous (IV) form. According to guidelines, the equivalent IV dose is approximately 75% of the previously established oral dosage.

#endocrinology


References:

1. PDR: https://www.pdr.net/drug-summary/Synthroid-levothyroxine-sodium-26 (last accessed January 12, 2020) 

2. Bolk N, Visser TJ, Nijman J, et al. Effects of evening vs morning levothyroxine intake: a randomized double-blind crossover trial. Arch Intern Med 2010; 170:1996. 

3. Skelin M, Lucijanić T, Liberati-Čizmek AM, et al. Effect of timing of levothyroxine administration on the treatment of hypothyroidism: a three-period crossover randomized study. Endocrine 2018; 62:432.