Comparison of serum levels and urinary excretion of three major anticonvulsants as between children and adults (Japanese)

Determination of serum levels and urinary excretion of phenobarbital (PB), diphenylhydantoin (DPH) and primidone (PRM) in a group of children and a group of adults with epilepsy was conducted. On comparable or higher doses per kg body weight, children had lower mean values of serum levels of all drugs tested than the adult patients. The excretion of PB (whether derived from the intake of PB or PRM) was also lower in children; this finding is consistent with faster catabolism of PB in children. The means of dose/excretion ratios of PRM was about the same in children as in adults. The urinary excretion of DPH by the patients of both groups was negligible. Potential factors influencing metabolism of anticonvulsant drugs were considered.