The pharmacokinetics of estazolam were examined in 17 healthy male subjects. Plasma concentration-time profiles were compared following the oral administration of one 1-mg tablet, two 1-mg tablets, and one 2-mg tablet. No statistically significant differences were detected among the mean time of maximal plasma concentration (Tmax), maximal plasma concentration (Cmax), area under the plasma concentration-time curve from zero to 72 hours (AUC), or half-life values for the 2-mg doses. Mean Cmax was 97.7 and 98.6 ng/ml and mean Tmax was 1.9 and 1.6 hours for two 1-mg tablets and one 2-mg tablet, respectively. Proportionately decreased Cmax and AUC were observed following the 1-mg dose. Mean Cmax was 54.7 ng/ml for the 1-mg dose. Mean Tmax and elimination half-life values were similar to those observed after the 2-mg doses. The overall harmonic mean half-life was 14.4 hours.