Starting Dose of Levothyroxine for the Treatment of Congenital Hypothyroidism

Abstract

The evidence for an effect of starting dose of levothyroxine on cognitive development, growth, or behavior is too weak to justify recommendations in favor of high- or standard-dose regimens. More reliable information, based on a randomized controlled trial of starting dose or a meta-analysis of the individual patient data currently available, is required to inform treatment policies.

Treatment and follow-up of children with transient congenital hypothyroidism

“…Moreover long-term follow-up studies found that high starting dose of L-T4 might cause more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration (Rovet and Ehrlich, 1995;Oerbeck et al, 2003). The starting dose of L-T4 we used is in conformity with what Campos and Rovet reported, but is much lower than the commonly used dose of 8~15 µg/(kg·d) or the 10.1~15.0 µg/(kg·d) reported from previous studies (Gruters et al, 1997;Hrytsiuk et al, 2002;Salerno et al, 2002). Patients with permanent CH require long-term substitution with a large dose of thyroxin (Rovet and Ehrlich, 1995).…”

Treatment and follow-up of children with transient congenital hypothyroidism

“…Moreover long-term follow-up studies found that high starting dose of L-T4 might cause more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration (Rovet and Ehrlich, 1995;Oerbeck et al, 2003). The starting dose of L-T4 we used is in conformity with what Campos and Rovet reported, but is much lower than the commonly used dose of 8~15 µg/(kg·d) or the 10.1~15.0 µg/(kg·d) reported from previous studies (Gruters et al, 1997;Hrytsiuk et al, 2002;Salerno et al, 2002). Patients with permanent CH require long-term substitution with a large dose of thyroxin (Rovet and Ehrlich, 1995).…”

Differential Effect of Fetal, Neonatal and Treatment Variables on Neurodevelopment in Infants with Congenital Hypothyroidism

“…However, our findings do not contradict the well-established knowledge of starting the treatment as soon as possible with a high dose of levothyroxine [17, 18, 19, 20]. …”

Hypothyroidism Among College Students and Its Association With Academic Performance: A Cross-Sectional Study

“…Ettleson et al [ 15 ] developed a survey to determine cognitive and behavioral symptoms associated with hypothyroidism and they found that more than 95% of the participants had fatigue, forgetfulness, feeling sleepy, and difficulty focusing, all these combined symptoms have negative impacts on the life and decrease the neurocognitive reserves that may affect the learning ability. Hrytsiuk et al [ 16 ] assessed the mean intelligence quotient (IQ) of 30 students who are treated for hypothyroidism and they found that their IQ scores were within the normal range. However, 77% showed at least one sign of impaired brain function and 26% of them had learning disorders.…”

Treatment and follow-up of children with transient congenital hypothyroidism

“…Moreover long-term follow-up studies found that high starting dose of L-T4 might cause more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration (Rovet and Ehrlich, 1995;Oerbeck et al, 2003). The starting dose of L-T4 we used is in conformity with what Campos and Rovet reported, but is much lower than the commonly used dose of 8~15 µg/(kg·d) or the 10.1~15.0 µg/(kg·d) reported from previous studies (Gruters et al, 1997;Hrytsiuk et al, 2002;Salerno et al, 2002). Patients with permanent CH require long-term substitution with a large dose of thyroxin (Rovet and Ehrlich, 1995).…”

Differential Effect of Fetal, Neonatal and Treatment Variables on Neurodevelopment in Infants with Congenital Hypothyroidism

“…However, our findings do not contradict the well-established knowledge of starting the treatment as soon as possible with a high dose of levothyroxine [17, 18, 19, 20]. …”

Hypothyroidism Among College Students and Its Association With Academic Performance: A Cross-Sectional Study

“…Ettleson et al [ 15 ] developed a survey to determine cognitive and behavioral symptoms associated with hypothyroidism and they found that more than 95% of the participants had fatigue, forgetfulness, feeling sleepy, and difficulty focusing, all these combined symptoms have negative impacts on the life and decrease the neurocognitive reserves that may affect the learning ability. Hrytsiuk et al [ 16 ] assessed the mean intelligence quotient (IQ) of 30 students who are treated for hypothyroidism and they found that their IQ scores were within the normal range. However, 77% showed at least one sign of impaired brain function and 26% of them had learning disorders.…”

Treatment and follow-up of children with transient congenital hypothyroidism

“…Moreover long-term follow-up studies found that high starting dose of L-T4 might cause more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration (Rovet and Ehrlich, 1995;Oerbeck et al, 2003). The starting dose of L-T4 we used is in conformity with what Campos and Rovet reported, but is much lower than the commonly used dose of 8~15 µg/(kg·d) or the 10.1~15.0 µg/(kg·d) reported from previous studies (Gruters et al, 1997;Hrytsiuk et al, 2002;Salerno et al, 2002). Patients with permanent CH require long-term substitution with a large dose of thyroxin (Rovet and Ehrlich, 1995).…”

Differential Effect of Fetal, Neonatal and Treatment Variables on Neurodevelopment in Infants with Congenital Hypothyroidism

“…However, our findings do not contradict the well-established knowledge of starting the treatment as soon as possible with a high dose of levothyroxine [17, 18, 19, 20]. …”

Hypothyroidism Among College Students and Its Association With Academic Performance: A Cross-Sectional Study

“…Ettleson et al [ 15 ] developed a survey to determine cognitive and behavioral symptoms associated with hypothyroidism and they found that more than 95% of the participants had fatigue, forgetfulness, feeling sleepy, and difficulty focusing, all these combined symptoms have negative impacts on the life and decrease the neurocognitive reserves that may affect the learning ability. Hrytsiuk et al [ 16 ] assessed the mean intelligence quotient (IQ) of 30 students who are treated for hypothyroidism and they found that their IQ scores were within the normal range. However, 77% showed at least one sign of impaired brain function and 26% of them had learning disorders.…”