Maintenance drug treatment of panic disorder. I. Results of a prospective, placebo-controlled comparison of alprazolam and imipramine.

One hundred six patients diagnosed according to DSM-III as suffering from agoraphobia with panic disorder, panic disorder with limited phobic avoidance, or uncomplicated panic disorder entered an acute 8-week treatment phase. Patients who improved received an additional 6 months' maintenance treatment. Significantly more patients treated with alprazolam than with imipramine hydrochloride or placebo remained in therapy and experienced panic attack and phobia relief during the acute treatment phase. During the maintenance phase, neither tolerance nor daily dose increase was observed. All patients who completed the maintenance phase (27 in the alprazolam group, 11 in the imipramine group, and 10 in the placebo group) were panic free at the end of 8 months of study treatment. Alprazolam therapy was effective and well tolerated at a mean daily dose of 5.7 mg. Imipramine hydrochloride (175 mg/d) also produced significant panic relief but was associated with poor patient acceptance.