Time course of carbamazepine self-induction.

Carbamazepine concentrations in plasma during repetitive oral dosing were analyzed by means of a nonlinear, variable parameter, regression program (VARPARM) assuming dose-to-dose changes in the apparent elimination rate constant of the drug. There was evidence of significant self-induction of carbamazepine metabolism as early as 1 or 2 days after initiation of the multiple-dose study. Additional self-induction appears to occur after about 2 weeks of treatment. The time course of carbamazepine self-induction appears to be complex, discontinuous, and prolonged.