Maintenance drug treatment for panic disorder. II. Short- and long-term outcome after drug taper.

Forty-eight patients with panic disorder completing 8 months of maintenance treatment with alprazolam (mean dose, 5.2 mg [n = 27]), imipramine hydrochloride (mean dose, 175 mg [n = 11]), or placebo (mean dose, 8.0 pills [n = 10]) underwent a gradual taper from medication over a 4-week period. A withdrawal syndrome was observed in almost all alprazolam-treated patients but in only a few imipramine- or placebo-treated patients. The clinical worsening of withdrawal symptoms after discontinuation tended to subside over the course of 3 medication-free weeks, but 33% of alprazolam-treated patients were unable to discontinue their medication regimen successfully. Severity of panic attacks at baseline but not daily alprazolam dose appeared as a significant independent predictor of taper difficulty. Forty-nine percent of the total study population continue to receive drug therapy: 82% alprazolam and 18% imipramine. Among patients who received alprazolam during study treatment and at follow-up, the mean daily dose was substantially reduced (6.1 vs 1.6 mg [n = 14]). At follow-up, after 1 year of naturalistic treatment for panic symptoms and combining 8-month completers and study dropouts, there were no significant differences in remission (68% to 71%) or in antipanic medication intake (39% to 56%) at follow-up for the three original treatment groups. However, 8-month study completers compared with study dropouts had a significantly higher remission rate (85% vs 55%).