Objective
To examine the effect of carbamazepine on the single oral dose pharmacokinetics of etizolam.Methods
Eleven healthy male volunteers received carbamazepine 200 mg/day or placebo for 6 days in a double-blind, randomized, crossover manner, and on the sixth day they received a single oral 1-mg dose of etizolam. Blood samplings and evaluation of psychomotor function by the Digit Symbol Substitution Test and Stanford Sleepiness Scale were conducted up to 24 h after etizolam dosing. Plasma concentration of etizolam was measured using high-performance liquid chromatography.Results
Carbamazepine treatment significantly decreased the peak plasma concentration (17.5±4.1 ng/ml versus 13.9±4.1 ng/ml; P<0.05), total="" area="" under="" the="" plasma="" concentration–time="" curve="" (194.8±88.9 ng h/ml="" versus="" 105.9±33.0 ng h/ml;="">P<0.001), and="" elimination="" half-life="" (11.1±4.6 h="" versus="" 6.8±2.8 h;="">P<0.01) of="" etizolam.="" no="" significant="" change="" was="" induced="" by="" carbamazepine="" in="" the="" two="" pharmacodynamic="">Conclusions
The present study suggests that carbamazepine induces the metabolism of etizolam.Keywords Etizolam - Carbamazepine - Metabolism - CYP3A4