Effects of carbamazepine on psychomotor performance in children as a function of drug concentration, seizure type, and time of medication.

Fifty children with well-controlled seizures who were receiving carbamazepine (CBZ) monotherapy were tested on a battery of cognitive and motor tests. Time of CBZ was varied so that the children were tested both shortly after CBZ (when daily CBZ concentrations approached their peak) and before CBZ (when CBZ concentrations approached daily low or trough levels). Testing was blind so that the examiner was unaware of the time of CBZ or the child's type of seizure. Results showed only one group difference related to seizure type and no differences linked to overall CBZ concentration as measured in saliva. Peak and trough concentrations were associated with changes in several variables, however. The children performed significantly better shortly after CBZ (peak concentration day) on measures of seat activity, attention span, and motor steadiness, whereas response times appeared to be influenced in a task-specific manner.