Autoimmune Thyroid Diseases in Children

Table 3

Conditions that increase L-T₄ requirements.

Pregnancy
Mucosal diseases of the small bowel
Jejuno-ileal bypass and small bowel resection
Drugs which impair L-T4 absorption (cholestyramine,
sucralfate, aluminum hydroxide, calcium carbonate, and
ferrous sulphate)
Drugs which may enhance CYP3A4 and thereby accelerate
L-T4 clearance (carbamazepine, rifampin, phenytoin,
estrogen, and sertraline)
Drugs which impair T4 to T3 conversion (amiodarone)
Conditions which may block type 1 deiodinase (selenium
deficiency due to dietary deficiencies as in phenylketonuria and
cystic fibrosis)
Cirrhosis