DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF A ONCE-A-DAY, SUSTAINED-RELEASE PREPARATION OF ALPRAZOLAM FOR THE TREATMENT OF PANIC DISORDER

Objective: The goals of this study were to assess the antipanic effica cy of a new, sustained-release formulation of alprazolam and to assess the safety and tolerability of once-a-day administration of 1-10 mg o f sustained-release alprazolam. Method: One hundred ninety-four patien ts with a diagnosis of agoraphobia with panic attacks or panic disorde r with limited phobic avoidance underwent a 1-week placebo washout bef ore being randomly assigned to groups receiving 8 weeks of double-blin d treatment with either sustained-release alprazolam or placebo. Resul ts: There was a significant treatment effect favoring sustained-releas e alprazolam (highest mean dose=4.7 mg/day) across almost all measures of anxiety, panic, and phobic avoidance, despite a significantly high er dropout rate in patients receiving placebo. Eighty-five percent of the patients treated with sustained-release alprazolam, compared with 61% of the patients given placebo, reported complete blockade of panic attacks by the end of 6 weeks of treatment. Sedation was the most com monly reported adverse effect. Discontinuation of sustained-release al prazolam was associated with moderate but transient levels of distress in 48% of the patients; discontinuation of placebo led to distress in only 10% of the patients. Nonetheless, there was no difference in the proportion of patients who were able to remain off the study drug for at least 2 weeks. Conclusions: These results suggest that sustained-r elease alprazolam is highly effective in the acute treatment of panic disorder at doses comparable to those in the originally marketed compr essed tablet of alprazolam. The medication was well tolerated but show ed rebound effects during a rapid drug taper after 6 weeks of treatmen t.