Time-dependent kinetics I: Exponential autoinduction of carbamazepine in monkeys.

The pharmacokinetics of carbamazepine were studied during a week-long infusion of the drug in 60% polyethylene glycol 400 solution in three rhesus monkeys. Serum concentrations approached steady state within 8-16 hr and then rapidly declined, within 72 hr, to a new asymptotic level approximately 46% of the maximum steady-state concentration. Serum concentrations remained at that level during the rest of the experimental period. The decline from the maximum value to the asymptotic steady state was exponential. It is postulated that the decline in the steady-state concentration is due to autoinduction by carbamazepine of its own metabolism.