Abstract
The absorption of riboflavin (administered as riboflavin-5'-phosphate) was studied in infants and children with thyroid disorders. The kinetics of elimination and the urinary recovery of riboflavin after intramuscular injection of the vitamin did not differ in hypothyroid and hyperthyroid children. On the other hand, oral administration of a large dose of riboflavin resulted in much more than normal absorption in hypothyroid children and in less than normal absorption in hyperthyroid children. Riboflavin absorption became normal in both groups upon successful treatment of the thyroid disorder. The duration of absorption was considerably prolonged in the hypothyroid children and shorter than normal in the hyperthyroid children. This is consistent with the hypothesis that the differences in the extent of absorption are caused by differences in intestinal transit rates due to the thyroid disease. It is likely that changes in intestinal transit rate will also affect the absorption of some drugs. This possibility should be taken into consideration when assessing the response of patients with thyroid disorders to oral medication.
- Received June 19, 1972.
- Accepted August 18, 1972.
- Copyright © 1972 by the American Academy of Pediatrics
