Evaluation of L-thyroxine requirement in treatment of congenital hypothyroidism.
The optimal daily requirement of L-T4 in replacement therapy for hypothyroidism was evaluated in evaluated in 24 cases of congenital hypothyroidism and 3 of juvenile myxedema, ranging from 3 to 30 years of age. The optimal dose of L-T4, defined as the minimal dose necessary to suppress the serum concentration of TSH into the normal range, was determined in each patient. The optimal dose of L-T4 between 3 and 5 years of age was 5-7 microgram/kg/day, which was higher than a level of 2-4 microgram/kg/day in adult. All patients appeared clinically euthyroid, and their serum concentration of T4 and T3 remained within the normal range while the optimal dose of L-T4 was being administered. These observations imply that physiologic requirement of L-T4 are lower than previously recommended dosages. Further studies to establish more precise therapeutic guidelines are needed.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003409:Congenital Hypothyroidism; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D008297:Male; D009230:Myxedema / Q000188:drug therapy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage* / Q000627:therapeutic use
D013972:Thyrotropin; D013974:Thyroxine