Effect of high versus low initial doses of L-thyroxine for congenital hypothyroidism on thyroid function and somatic growth

Jones, Jeremy; Gellén, Balázs; Paterson, W. F.; Beaton, Stephen; Donaldson, Malcolm

doi:10.1136/adc.2007.120618

Cited by 34 publications

(29 citation statements)

References 26 publications

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“…Jones et al (20) evaluated the effects of three different doses of LT4 therapy on somatic growth at 3 months and at the age of 3 years in their study, and found no significant differences in weight, height, and head circumference among groups. Salerno et al (14) identified the final height of patients who received highdose LT4 therapy ( > 8 μg/kg/day) to be similar to that of patients who initially received low-dose LT4 therapy ( < 8 μg/kg/day).…”

Section: Discussionmentioning

confidence: 98%

Levothyroxine replacement in primary congenital hypothyroidism: the higher the initial dose the higher the rate of overtreatment

Tuhan

Abacı

Cicek

et al. 2016

Journal of Pediatric Endocrinology and Metabolism

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Section: Discussionmentioning

confidence: 98%

Levothyroxine replacement in primary congenital hypothyroidism: the higher the initial dose the higher the rate of overtreatment

Tuhan

Abacı

Cicek

et al. 2016

Journal of Pediatric Endocrinology and Metabolism

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“…Regarding the initial L-thyroxin (L-T4) dose, although both the American academy of pediatrics and the European Society for pediatric endocrinology recommend 10 - 15 μg/kg/day as the initial dose (26, 27), we still could not reach a definitive conclusion. Although, most studies included in our review favor using a high initial treatment dose (17, 28-33), some studies disagree. For instance, the study of Touati et al found that a systematic higher initial dosage could expose many infants to complications of hyperthyroidism, whereas an initial dosage of 7.5 - 8.0 μg/kg per day, with early assessment of FT4, FT3, and TSH levels, is adequate for treatment of the majority of infants with CH (21).…”

Section: Discussionmentioning

confidence: 96%

Congenital Hypothyroidism: Optimal Initial Dosage and Time of Initiation of Treatment: A Systematic Review

Rahmani

Yarahmadi

Etemad

et al. 2016

Int J Endocrinol Metab

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ContextAppropriate management of neonates, tested positive for congenital hypothyroidism (CH), in particular, the initial dosage of levothyroxine and the time of initiation of treatment is a critical issue. The aim of this study was to assess all current evidence available on the subject to ascertain the optimal initial dose and optimal initiation time of treatment for children with CH.Evidence AcquisitionIn this study, all published research related to the initiation treatment dose and the onset time of treatment in congenital hypothyroidism were reviewed. The searched electronic databases included Medline, Science direct, Scopus EMBASE, PsycINFO, Cochrane, BIOSIS and ISI Web of Knowledge. Additional searches included websites of relevant organizations, reference lists of included studies, and issues of major thyroid and pediatrics journals published within the past 35 years. Studies were included if they were written in English and investigated levothyroxine dose or timing of treatment or both, used for the treatment of children with congenital hypothyroidism.ResultsTwo thousand three hundred and seventy-four articles (excluding duplicates) were retrieved from the primary search. After reviewing the titles, abstracts and full-texts of studies, eventually, 22 studies were found that met our inclusion criteria. Amongst these, 17 and 12 evaluated outcomes of different treatment doses and treatment timing, respectively. Overall, the majority of these studies emphasized the initial high dose of levothyroxine and early treatment of newborns with hypothyroidism. There were, however, some studies that disagreed with increasing levothyroxine dose at initiation of treatment.ConclusionsConsidering the results of this review, apparently there is no difference in opinion regarding the early initiation of treatment, whereas determining the optimal dose of levothyroxine for start of treatment in CH patients still remains a controversial issue, demonstrating the need for further studies, despite the fact that use of high doses can lead to rapid normalization of biochemical indices, although this may cause complications.

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“…Moreover, the burden to the national health insurance system cannot be ignored. Additionally, recent evidence suggests that exposure to excess thyroid hormone may be as harmful as HT to long-term cognitive development [45,46]. In the United States, more than one third of the children who are treated for CH discontinue treatment within 36 months, and some of these patients stop treatment on their own without medical supervision [3].…”

Section: Discussionmentioning

confidence: 99%

Feasibility of an Early Discontinuation of Thyroid Hormone Treatment in Very-Low-Birth-Weight Infants at Risk for Transient or Permanent Congenital Hypothyroidism

Jung

Jin

Chung³

2016

Horm Res Paediatr

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Background/Aims: This prospective study was conducted to investigate the feasibility of an early discontinuation of thyroid hormone treatment in very-low-birth-weight (VLBW) infants with congenital hypothyroidism (CH). Methods: We enrolled VLBW infants between January 2011 and December 2012. The infants were divided into the hypothyroid and normal thyroid function groups according to the results of a thyroid function test. We performed an early off-therapy trial at 24 months of age. Results: Of the 182 VLBW infants enrolled, 15 were lost to follow-up and 167 were finally enrolled. In total, 24 infants (14.4%) were assigned to the hypothyroid function group and were treated with thyroid hormone. Younger gestational age and a lower birth weight were associated with hypothyroid function. In the hypothyroid function group, hypothyroidism (HT) and hyperthyrotropinemia (HTT) were observed in 13 and 11 infants, respectively. There were no differences in the clinical characteristics between the HT and HTT groups. Overall, 24 infants discontinued thyroxine medication at 24 months of age after normal results had been confirmed by radiologic work-ups, including thyroid ultrasonography and technetium-99m scans. All infants were successfully weaned off thyroxine and maintained euthyroid function. Conclusion: Early discontinuation of thyroid hormone replacement therapy is possible in the majority of VLBW infants with CH.

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Effect of high versus low initial doses of L-thyroxine for congenital hypothyroidism on thyroid function and somatic growth

Abstract: An initial T4 dose of 50 mug daily, normalises thyroid function several months earlier than lower-dose regimes, with no evidence of sustained somatic overgrowth between 3 months and 3 years.

Cited by 34 publications

References 26 publications

Levothyroxine replacement in primary congenital hypothyroidism: the higher the initial dose the higher the rate of overtreatment

Levothyroxine replacement in primary congenital hypothyroidism: the higher the initial dose the higher the rate of overtreatment

Congenital Hypothyroidism: Optimal Initial Dosage and Time of Initiation of Treatment: A Systematic Review

Feasibility of an Early Discontinuation of Thyroid Hormone Treatment in Very-Low-Birth-Weight Infants at Risk for Transient or Permanent Congenital Hypothyroidism

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