Levothyroxine Replacement Dose for Primary Hypothyroidism Decreases with Age
Abstract
We studied 23 elderly (other than 65) and 44 younger ambulatory adult patients with primary hypothyroidism to ascertain the dose of levothyroxine needed for complete replacement in relation to age. The elderly patients (average age, 75.7 years) needed an average 118 microgram/d whereas the younger patients (average age, 48.1 years) needed 158 microgram/d. The data indicate that thyroxine requirement may decrease continuously with age. This decrease probably reflects the progressive decrease in thyroxine degradation rate that occurs with age.
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LT4 replacement doses tend to decrease with age when they are titrated based on serum TSH.
“LT4 replacement doses tend to decrease with age when they are titrated based on serum TSH (213,215,216,219,220).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [213]
Most studies examining factors affecting LT4 dose were retrospective chart reviews, but some were prospective.
“Most studies examining this issue were retrospective chart reviews (47,212-224), but some studies were prospective (38,225-229).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [213]
Some studies estimate higher LT4 doses of 2.0-2.1 μg/kg for some patient groups.
“Based on body weight, hypothyroid patients with minimal endogenous thyroid function require LT4 doses of 1.6-1.8 l g/kg of actual body weight (38,47,212,213,215-217,226,227), although some studies estimate higher doses of 2.0-2.1 l g/kg for some patient groups (212,213,226).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [213]
Hypothyroid patients with minimal endogenous thyroid function require LT4 doses of 1.6-1.8 μg/kg actual body weight.
“Based on body weight, hypothyroid patients with minimal endogenous thyroid function require LT4 doses of 1.6-1.8 l g/kg of actual body weight (38,47,212,213,215-217,226,227), although some studies estimate higher doses of 2.0-2.1 l g/kg for some patient groups (212,213,226).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [213]
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References 6 · Cited by 163
- Authors
- ROSENBAUM, R. L., & BARZEL, U. S.
- Affiliations
- Bronx, New York
- Corresponding author
- ROSENBAUM, ROBERT L.
- Venue
- Annals of Internal Medicine
- Publisher
- American College of Physicians
- Published
- 1982-01-01
- Volume
- 96
- Issue
- 1
- Pages
- 53-55
- ISSN
- 0003-4819 (ISSN-L)
- 1539-3704
- OpenAlex
- W2088527682
- Cited by
- 163
- References
- 6
- Citations by year
- 2026: 1 · 2025: 5 · 2024: 4 · 2023: 2 · 2022: 2 · 2021: 3 · 2020: 3 · 2019: 5 · 2017: 5 · 2016: 4 · 2015: 3 · 2014: 5 · 2013: 6 · 2012: 6
- FWCI
- 8.26
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Annals of Internal Medicine (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 › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
- Keywords
- levothyroxine, primary hypothyroidism, elderly patients, thyroid hormone replacement
- MeSH terms
- Age Factors, Aged, Body Weight, Humans, Hypothyroidism, Middle Aged, Thyroxine
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