[Treatment of congenital hypothyroidism by L-thyroxine in solution. Posology]

A solution of levothyroxine (5 micrograms/drop) has been used in congenital hypothyroidism detected after neonatal screening. Optimal doses were variable among individual patients. With 5-7 micrograms/kg during the first month of treatment, then 4 to 5 micrograms/kg, it was usually possible to obtaining normal plasma T4, which seems more important that to normalize TSH. Overdosage is to be avoided as well as insufficiency of treatment.