Cited by 60Thyroid Disorders and TreatmentsThyroid and Parathyroid SurgeryGastroesophageal reflux and treatments

Tablet levothyroxine (L-T4) malabsorption induced by proton pump inhibitor: a problem that was solved by switching to L-T4 in soft gel capsule

Vita, Roberto, Benvenga, Salvatore·2014·Endocrine Practice

Abstract

Objective To report a patient in whom the impaired absorption of tablet levothyroxine (L-T4) due to a proton pump inhibitor (PPI) use was corrected by switching the patient to the soft gel capsule.Methods A woman with Hashimoto's thyroiditis-associated hypothyroidism (serum thyroid-stimulating hormone [TSH] 6.8-9.6 mU/L) had been treated with tablet L-T4 (100 μg/day). Because she used to take pantoprazole just before L-T4 in the morning, TSH failed to normalize (4.4-6.5 mU/L). Thus, the daily dose had been progressively increased to 125 and 150 μg/day, with serum TSH levels of 2.4 and 0.6 mU/L, respectively.Results While maintaining pantoprazole, we switched the tablet L-T4 (150 g/day) to a soft gel capsule (125 μg/day; Tirosint® capsule, IBSA, Lugano, Switzerland) and after 2 months, to 100 μg/day. Serum TSH was lower than under the equivalent regimens with the tablet: 0.5 versus 2.4 mU/L (125 μg/day) and 2.4 versus 4.4 to 6.5 mU/L (100 μg/day). Upon switching back to the tablet (100 μg/day), serum TSH increased to 3.2 and 4.7 mU/L and then dropped to 2.7-3.0 mU/L when the dose was increased to 125 μg/day. We also acutely evaluated the intestinal absorption of L-T4 by administering 600 μg LT4 as a tablet or soft gel capsule while maintaining pantoprazole. Pharmacokinetic indices showed better and faster absorption for the soft gel capsule versus tablet (area under the curve [AUC]0-4h = 16,240 vs. 10,960 nmol/L x 4 hours, maximum absorption [Cmax] = 108 vs. 73 nmol/L, and time of maximum absorption [Tmax] = 120 minutes vs. 180 minutes).Conclusion Confirming in vitro studies conducted by other authors, the soft gel capsule L-T4 is negligibly affected by changes in gastric pH compared to tablet L-T4.

Integrity signals

Registry

Crossref · 10.4158/ep13316.cr

Cites

14 of 14 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Vita, R., & Benvenga, S.
Affiliations
University of Messina (IT)
Corresponding author
Vita, Roberto
Venue
Endocrine Practice
Publisher
Elsevier BV
Published
2014-03
Volume
20
Issue
3
Pages
e38-e41
ISSN
1530-891X (ISSN-L)
OpenAlex
W2013324388
Cited by
60
References
14
Citations by year
2025: 1 · 2024: 4 · 2023: 2 · 2022: 7 · 2021: 6 · 2020: 3 · 2019: 6 · 2018: 4 · 2017: 7 · 2016: 8 · 2015: 7 · 2014: 4 · 2013: 1
FWCI
5.24
Type
journal article
Language
en
Open access
closed
Locations
  • Endocrine Practice (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
  • Health Sciences › Medicine › Surgery › Thyroid and Parathyroid Surgery
  • Health Sciences › Medicine › Gastroenterology › Gastroesophageal reflux and treatments
Keywords
levothyroxine, drug malabsorption, proton pump inhibitors, pantoprazole, tablet formulation, Hashimoto's thyroiditis, hypothyroidism, thyroid-stimulating hormone, pharmacokinetics, drug-drug interactions, antacids, dose adjustment, TSH normalization, antithyroid drugs

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review