Disposition of anticonvulsants in childhood.

There have been great advances in our understanding of the childhood epilepsies within recent years and at the same time there has been increasing awareness of the pharmacokinetic properties of the anticonvulsant drugs. It has been increasingly recognised that pharmacokinetic parameters of anticonvulsants are not constant, but are subject to influences by a number of physiological variables over which age is a major determinant. As changes in pharmacokinetic parameters will alter dosage requirements, dosage regimens cannot be transferred from one age group to another without the risk of underdosing or overdosing. Drug monitoring techniques are being increasingly used as a guide to correct dosing but knowledge of the limitations of monitoring is as important as knowledge of potential benefits for monitoring to be used correctly. An overview of the important pharmacokinetic properties of anticonvulsant drugs is provided, with emphasis on findings in children where such data are available.