The objective of this study was to evaluate the pharmacokinetic interaction between zolpidem and carbamazepine in healthy volunteers. The study consisted of 2 periods: period 1 (reference), when each volunteer received a single dose of 5 mg zolpidem, and period 2 (test), when each volunteer received a single dose of 5 mg zolpidem and 400 mg carbamazepine. Between the 2 periods, the participants were treated for 15 days with a single daily dose of 400 mg carbamazepine. Pharmacokinetic parameters of zolpidem administered in each treatment period were calculated using noncompartmental analysis. In the 2 periods of treatments, the mean peak plasma concentrations (C(max)) were 59 ng/mL (zolpidem alone) and 35 ng/mL (zolpidem after pretreatment with carbamazepine). The t(max), times taken to reach C(max), were 0.9 hours and 1.0 hour, respectively, and the total areas under the curve (AUC(0-∞)) were 234.9 ng·h/mL and 101.5 ng·h/mL, respectively. The half-life of zolpidem was 2.3 and 1.6 hours, respectively. Carbamazepine interacts with zolpidem in healthy volunteers and lowers its bioavailability by about 57%. The experimental data demonstrate the pharmacokinetic interaction between zolpidem and carbamazepine and suggest that the observed interaction may be clinically significant, but its relevance has to be confirmed.