2012 ETA Guidelines: The Use of L-T4 + L-T3 in the Treatment of Hypothyroidism

Abstract

Background

Data suggest symptoms of hypothyroidism persist in 5–10% of levothyroxine (L-T4)-treated hypothyroid patients with normal serum thyrotrophin (TSH). The use of L-T4 + liothyronine (L-T3) combination therapy in such patients is controversial. The ETA nominated a task force to review the topic and formulate guidelines in this area.

Methods

Task force members developed a list of relevant topics. Recommendations on each topic are based on a systematic literature search, discussions within the task force, and comments from the European Thyroid Association (ETA) membership at large.

Results

Suggested explanations for persisting symptoms include: awareness of a chronic disease, presence of associated autoimmune diseases, thyroid autoimmunity per se, and inadequacy of L-T4 treatment to restore physiological thyroxine (T4) and triiodothyronine (T3) concentrations in serum and tissues. There is insufficient evidence that L-T4 + L-T3 combination therapy is better than L-T4 monotherapy, and it is recommended that L-T4 monotherapy remains the standard treatment of hypothyroidism. L-T4 + L-T3 combination therapy might be considered as an experimental approach in compliant L-T4-treated hypothyroid patients who have persistent complaints despite serum TSH values within the reference range, provided they have previously received support to deal with the chronic nature of their disease, and associated autoimmune diseases have been excluded. Treatment should only be instituted by accredited internists/endocrinologists, and discontinued if no improvement is experienced after 3 months. It is suggested to start combination therapy in an L-T4/L-T3 dose ratio between 13:1 and 20:1 by weight (L-T4 once daily, and the daily L-T3 dose in two doses). Currently available combined preparations all have an L-T4/L-T3 dose ratio of less than 13:1, and are not recommended. Close monitoring is indicated, aiming not only to normalize serum TSH and free T4 but also normal serum free T4/free T3 ratios. Suggestions are made for further research.

Conclusion

L-T4 + L-T3 combination therapy should be considered solely as an experimental treatment modality. The present guidelines are offered to enhance its safety and to counter its indiscriminate use.

Affiliations

^aDepartment of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands

^bEndocrine Unit, Evgenidion Hospital, University of Athens Medical School, Athens, Greece

^cFederal Endocrinological Scientific Center, Moscow, Russia

^dDepartment of Endocrinology, Herlev Hospital, Herlev, Denmark

^eDepartment of Endocrinology, Royal Free Hampstead NHS Trust, London, UK

Author notes

*Wilmar M. Wiersinga, Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreef 9, NL–1105 AZ Amsterdam (The Netherlands), E-Mail w.m.wiersinga@ 123456amc.uva.nl

Authors represent the task force for these guidelines, instituted by the ETA Executive Committee and Guidelines Board.

Journal

Journal ID (nlm-ta): Eur Thyroid J

Journal ID (iso-abbrev): Eur Thyroid J

Journal ID (publisher-id): ETJ

Title: European Thyroid Journal

Publisher: S. Karger AG (Allschwilerstrasse 10, P.O. Box · Postfach · Case postale, CH–4009, Basel, Switzerland · Schweiz · Suisse, Phone: [phone], Fax: [phone], [e-mail] )

ISSN (Print): 2235-0640

ISSN (Electronic): 2235-0802

Publication date (Print): July 2012

Publication date (Electronic): 13 June 2012

Publication date PMC-release: 13 June 2012

Volume: 1

Issue: 2

Pages: 55-71

ID: 24782999 ID: 3821467 ID: 10.1159/000339444 ID: etj-0001-0055

Copyright statement: Copyright © 2012 European Thyroid Association Published by S. Karger AG, Basel

Counts

Tables: 6, References: 79, Pages: 17

Categories

Subject: Guidelines