Pharmacokinetics of carbamazepine in the neonate and in the child.

1. Pharmacokinetic of carbamazepine were made in 7 new-borns and in 5 children. They were hospitalized for epilepsy and were receiving drugs such as phenobarbital alone or in association with other antiepileptic drugs, but not with carbamazepine. 2. The drug was given by oral route with a mean dose of 17.2 mg.kg-1. 3. The determination of carbamazepine concentration in serum was made by gas liquid chromatography on a 50 microliter sample. 4. A one compartment body model was used to determine the pharmacokinetic constants with first order rate constants for absorption and elimination. 5. Absorption was generally delayed by about half an hour, the maximum concentrations ranging from 3.14 to 10 microgram.ml-1 at 2 and 9 hr after administration. The mean half-life for absorption was 1.42 +/- 0.34 hr. The mean half-life for elimination was 8.76 +/- 0.85 hr. The half-life for elimination was much shorter than those already described even in multiple dosing epileptic adult patients. The pharmacokinetic parameters were used to predict blood levels in chronic treatment in 3 children. The predicted steady state concentrations disagreed with the concentrations measured.