The effect of sertindole (a new selective antipsychotic compound) on the pharmacokinetic disposition of alprazolam was investigated. Fourteen subjects who completed the study received a single 1 mg dose of alprazolam without or with concomitant sertindole 12 mg daily. Coadministration of sertindole and alprazolam led to a half-hour decrease (P < 0.05) in mean Tmax value (alone: 1.2 h, in combination: 0.7 h) and a 1.6-h increase in the mean t1/2 value (12.5 +/- 3.2 versus 14.3 +/- 3.4 h, P < 0.05) of alprazolam. The mean Cmax (18.5 +/- 4.9 versus 18.5 +/- 4.8 ng/ml) and AUC (266 +/- 68 versus 275 +/- 57 ng x h/ml) values of alprazolam did not change statistically significantly in the presence of sertindole (P > 0.05). These pharmacokinetic changes are minor and not considered to be of clinical significance. Although both sertindole and alprazolam are substrate for CYP3A4 (cytochrome P-450 3A4), the results in this study suggest that sertindole is not an inhibitor of the metabolism of alprazolam.