Carbamazepine dose-frequency requirement in children.

The dose-frequency requirement for carbamazepine (CBZ) in children was investigated using serial saliva samples to determine the daily fluctuation in drug levels. Mixed saliva was collected from 6 children (aged between 6 and 13 years) in a steady state, on each of two different dose-frequency resulted in smaller fluctuations in saliva concentration and a shorter time with levels outside the therapeutic range. Toxic features and convulsions appeared to be related to peak and trough concentrations. There was no apparent relationship between the total dose and the mean saliva concentration. The saliva CBZ half-lives in 2 children were 7.3 and 12.7 hours, and the apparent volumes of distribution (saliva) were 1.6 and 1.5 l/kg respectively. Saliva CBZ concentrations are an efficient and convenient means of tailoring individual dosage, and can be used to provide the pharmacokinetic data that rational prescribing demands.