Autoinduction and steady-state pharmacokinetics of carbamazepine and its major metabolites.
1. The effect of carbamazepine (CBZ) dose change on mean plasma concentrations of CBZ, its two metabolites and apparent steady-state clearance was studied in 77 affectively ill patients receiving CBZ at doses of 100-1200 mg day-1. 2. Autoinduction of CBZ metabolism appeared to be complete within 1 week of starting CBZ therapy or dose change, and its degree was linearly related to CBZ daily dose. 3. Curvilinear plots were obtained for steady-state concentrations of CBZ and its -10,11-epoxide metabolite, and for the ratio of CBZ-10,11-epoxide to CBZ level, versus daily dose of CBZ. 4. On the contrary, steady-state concentration of CBZ-10,11-diol increased proportionately with the dose. This indicates that there is no dose dependency in absorption of CBZ, and that dose-dependent autoinduction of CBZ metabolism is the main cause of the curvilinear relationship between dose and steady-state concentration of CBZ and its intermediary metabolite, CBZ-10,11-epoxide.
Kudriakova
T B
TB
Mental Health Research Centre Russian AMS, Moscow.
Sirota
L A
LA
Rozova
G I
GI
Gorkov
V A
VA
D000328:Adult; D002220:Carbamazepine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
D002220:Carbamazepine; C004822:10,11-dihydro-10,11-dihydroxy-5H-dibenzazepine-5-carboxamide; C012227:carbamazepine epoxide