Combined Levothyroxine Plus Liothyronine Compared With Levothyroxine Alone in Primary Hypothyroidism

Clyde, Patrick W.; Harari, A; Getka, Eric J.; Shakir, K.M. Mohamed

doi:10.1001/jama.290.22.2952

Cited by 169 publications

(140 citation statements)

References 30 publications

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“…Based on Grozinsky-Glasberg et al 's (2006) metaanalysis and Ma et al's (2009) systematic review it can be summed up that combined T4 and T3 treatment does not improve well-being, cognitive function, or health status compared with T4 itself. This is proved with works by Appelhof et al, 2005;Clyde et al, 2003;Joffe et al, 2004;Meng et al, 2004;Nygaard et al, 2009;Regalbuto et al, 2007;Saravanan et al, 2005;Sawka et al, 2003;Siegmund et al, 2004;Valizadeh et al, 2009;Walsh et al, 2003 and others. Whereas first works signalled differences in favour of combined T4 and T3 (Bunevičius et al, 1999(Bunevičius et al, , 2002Bunevičius & Prange, 2000).…”

Section: Researches In Hypothyroidismsupporting

confidence: 53%

Psychosocial Factors in Patients with Thyroid Disease

Mandincová¹

2012

Thyroid and Parathyroid Diseases - New Insights Into Some Old and Some New Issues

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Section: Researches In Hypothyroidismsupporting

confidence: 53%

Psychosocial Factors in Patients with Thyroid Disease

Mandincová¹

2012

Thyroid and Parathyroid Diseases - New Insights Into Some Old and Some New Issues

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“…Several studies have recently reported that compared with levothyroxine alone, use of a combination of levothyroxine plus liothyronine produces no beneficial changes in cognitive performance in hypo-Effectiveness of thyroid supplement and tyrosine in Antarctica thyroid subjects (46)(47)(48). Other studies have reported moderate or no effects with T 4 supplementation (49,50).…”

Section: Discussionmentioning

confidence: 99%

Psychoneuroendocrine effects of combined thyroxine and triiodothyronine versus tyrosine during prolonged Antarctic residence

Palinkas

Reedy

Smith

et al. 2007

International Journal of Circumpolar Health

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Objectives. We previously reported that cognitive function improves with thyroxine and that there is a circannual pattern to mood and human TSH during Antarctic residence. To extend these findings, we examined the effects of tyrosine and a combined levothyroxine/ liothyronine supplement in euthyroid men and women who spent the austral summer (n=43) and/or winter (n=42) in Antarctica. Study Design. Randomized, placebo-controlled, clinical trial. Methods. Subjects were randomized to receive the following each day for 91.6±3.2 days in summer and/or 138.0± 3.2 days in winter: (1) 12g tyrosine mixed in 113g applesauce; (2) 50ug of levothyroxine and 12.5ug of liothyronine (T4-T3 Supplement); or (3) placebo. Cognitive performance and mood were assessed using the Automatic Neuropsychological Assessment Metric -Isolated and Confined Environments. Effectiveness of thyroid supplement and tyrosine in Antarctica Results. With placebo in summer, mood did not change while TSH decreased by 28%; in winter, there was a 136% degradation in mood (p<0.01) and TSH increased by 18%. With combined T4-T3 supplement, there was a 51% degradation in mood in summer compared with placebo (p<0.05) and TSH decreased by 57%; in winter there was a 135% degradation in mood while TSH was reduced by 26% (p<0.05). Tyrosine use in summer was associated with no change in mood and a 30% decline in TSH, while in winter there was a 47% improvement in mood and TSH decreased by 28% along with a 6% increase in fT3 (p<0.05). Conclusions. Administration of tyrosine leads to a significant reduction in serum TSH and improvement in mood in winter compared with placebo, while the combined T4-T3 supplement leads to a worsening of mood in summer and no improvement in winter. There appears to be a seasonal influence on the psychological response to interventions and the relationship to changes in TSH reductions. (Int J Circumpolar Health 2007; 66(5):401-417)

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“…This raises the question of whether LT4-treated subjects with low T3 levels could benefit from low-dose LT3 therapy to assist with body weight regulation. However, all but one randomized controlled studies of combined LT4/ LT3 in hypothyroid subjects failed to find any differences in weight between combined LT4/LT3 and LT4 monotherapy (31)(32)(33)(34)(35)(36)(37)(38)(39). In addition, REE was not affected in the study by Celi et al (30).…”

Section: Lt4 Therapy Energy Expenditure and Body Compositionmentioning

confidence: 91%

Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition

Samuels

Kolobova

Smeraglio

et al. 2016

Thyroid

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Background: Thyrotropin (TSH)-suppressive doses of levothyroxine (LT4) have adverse effects on bone and cardiac function, but it is unclear whether metabolic function is also affected. The objective of this study was to determine whether women receiving TSH-suppressive LT4 doses have alterations in energy expenditure or body composition. Methods: This study was a cross-sectional comparison between three groups of women: 26 women receiving chronic TSH-suppressive LT4 doses, 80 women receiving chronic replacement LT4 doses, and 16 untreated euthyroid control women. Subjects underwent measurements of resting energy expenditure (REE), substrate oxidation, and thermic effect of food by indirect calorimetry; physical activity energy expenditure by accelerometer; caloric intake by 24-hour diet recall; and body composition by dual X-ray absorptiometry. Results: REE per kilogram lean body mass in the LT4 euthyroid women was 6% lower than that of the LT4-suppressed group, and 4% lower than that of the healthy control group ( p = 0.04). Free triiodothyronine (fT3) levels were directly correlated with REE, and were 10% lower in the LT4 euthyroid women compared with the other two groups ( p = 0.007). The groups of subjects did not differ in other measures of energy expenditure, caloric intake, or body composition. Conclusions: LT4 suppression therapy does not adversely affect energy expenditure or body composition in women. However, LT4 replacement therapy is associated with a lower REE, despite TSH levels within the reference range. This may be due to lower fT3 levels, suggesting relative tissue hypothyroidism may contribute to impaired energy expenditure in LT4 therapy.

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Combined Levothyroxine Plus Liothyronine Compared With Levothyroxine Alone in Primary Hypothyroidism

Cited by 169 publications

References 30 publications

Psychosocial Factors in Patients with Thyroid Disease

Psychosocial Factors in Patients with Thyroid Disease

Psychoneuroendocrine effects of combined thyroxine and triiodothyronine versus tyrosine during prolonged Antarctic residence

Effects of Levothyroxine Replacement or Suppressive Therapy on Energy Expenditure and Body Composition

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