Free and total serum concentrations of carbamazepine and carbamazepine-10,11-epoxide in infancy and childhood.

Abstract

Total and free serum concentrations of carbamazepine (CBZ) and carbamazepine-10,11-epoxide (CBZ-E) at steady state were determined in 10 infants (ages 4-13 months), 10 preschool children (ages 3-5 years), and 11 school children (ages 7-11 years) receiving equivalent doses of CBZ alone. Free and total CBZ levels tended to increase with increasing age, while CBZ-E levels did not show any significant age dependency. As a result, CBZ-E/CBZ ratios were higher in infants and preschool children than in the older age group. The degree of plasma protein binding of CBZ and CBZ-E did not show any important differences among the various groups. These data provide evidence that, within a pediatric population, CBZ shows age-related dispositional changes which may be clinically important.