Response of panic disorder to fixed doses of alprazolam or imipramine.

This paper reports the results of a double-blind comparison of fixed daily doses of 6 mg of alprazolam, 2 mg of alprazolam, 225 mg of imipramine, and placebo for 8 weeks in 81 patients who met DSM-III criteria for panic disorder with or without agoraphobia. Final scores on eight clinical measures were analyzed from all patients who entered the study and from the subset who completed at least 4 weeks of treatment. Eighty-six percent of the high-dose alprazolam patients completed the study. Only 50% of the imipramine patients completed 8 weeks of treatment, apparently because of activation early in treatment and slow onset of therapeutic effects. This study confirmed the therapeutic effectiveness and safety of alprazolam, especially at the higher dose, in panic disorder. It also confirmed the therapeutic effectiveness of imipramine among patients who tolerated the drug. It suggested the usefulness of a flexible, individual approach to dose escalation with imipramine. Methodologically the study underscored the importance of using multiple approaches to the analysis of clinical data from therapeutic trials of psychotropic agents with complex effects that may contribute to patients' premature termination.