Lactose intolerance and levothyroxine malabsorption: a review of the literature and report of a series of patients treated with liquid L-T4 without lactose

Front Endocrinol (Lausanne). 2024 Apr 11:15:1386510. doi: 10.3389/fendo.2024.1386510. eCollection 2024.

Abstract

In hypothyroid patients needing large doses of levothyroxine (L-T4) (>1.7-2 μg/kg/day) to reach euthyroidism, lactose intolerance (LI) needs to be excluded, owing to the high prevalence in the population. If LI is present, a lactose-free diet decreases the rate of L-T4 malabsorption. However, an increased requirement of L-T4 is described in patients with LI, which can be beneficially treated using lactose-free L-T4 formulation. The lactose-free liquid L-T4 formulation is able to circumvent LI malabsorption leading to the normalization of thyroid-stimulating hormone (TSH) in patients with subclinical hypothyroidism and long-term stable TSH levels.

Keywords: autoimmune thyroiditis; hypothyroidism; lactose intolerance; liquid L-T4; malabsorption.

Publication types

  • Review
  • Case Reports

MeSH terms

  • Adult
  • Female
  • Humans
  • Hypothyroidism* / drug therapy
  • Hypothyroidism* / metabolism
  • Lactose
  • Lactose Intolerance* / drug therapy
  • Malabsorption Syndromes / drug therapy
  • Malabsorption Syndromes / metabolism
  • Male
  • Middle Aged
  • Thyrotropin / blood
  • Thyrotropin / metabolism
  • Thyroxine* / pharmacokinetics
  • Thyroxine* / therapeutic use

Substances

  • Thyroxine
  • Lactose
  • Thyrotropin

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This retrospective study and the publication fees for this manuscript were funded by IBSA.