To investigate whether alprazolam (ALP) coprescription early in the imipramine (IMI) treatment of panic disorder would improve overall treatment response to IMI alone, 48 panic disorder patients were randomly assigned to receive either IMI plus placebo or IMI plus ALP for 4-6 weeks, followed by 2 weeks of IMI plus placebo-ALP taper and 2 more weeks of IMI alone. Although patients in the IMI plus ALP group improved more quickly, significantly more patients in the IMI plus ALP group could not follow the taper schedule. The results suggest that studies employing other benzodiazepines or other ALP dosage or taper schedules would be required to demonstrate any benefit for the IMI plus early benzodiazepine cotreatment strategy over IMI alone in the routine pharmacologic management of panic disorder.