Rationale: Few randomized, placebo-controlled trials have evaluated the comparative efficacy and tolerability of more than one pharmacological agent for panic disorder.
Objectives: The primary objective of this study was to compare the efficacy and tolerability of venlafaxine extended release (ER) with placebo in treating panic disorder. Secondary objectives included comparing paroxetine with venlafaxine ER and placebo.
Methods: Outpatients aged > or =18 years (placebo, n = 157; venlafaxine ER 75 mg, n = 156; venlafaxine ER 225 mg, n = 160; paroxetine, n = 151), with a primary diagnosis of panic disorder (+/-agoraphobia) based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria for > or =3 months were randomly assigned to receive venlafaxine ER (titrated to 75 mg/day or 225 mg/day), paroxetine (titrated to 40 mg/day), or placebo for 12 weeks. The primary efficacy measure was the percentage of patients free of full-symptom panic attacks (> or = four symptoms) at endpoint. Key secondary outcomes included the Panic Disorder Severity Scale (PDSS) mean score change and response.
Results: At endpoint, all active treatment groups showed a significantly (P < 0.01) greater proportion of patients free of full-symptom panic attacks, compared with placebo, and were superior (P < 0.05) on most secondary measures. The venlafaxine ER 225 mg group had significantly (P < 0.05) greater mean PDSS score improvement than the paroxetine group (-12.58 vs -11.87) and a significantly higher proportion of patients free of full symptom panic attacks (70.0 vs 58.3%). Both drugs were generally well tolerated.
Conclusion: Venlafaxine ER 75 mg/days and 225 mg/days and paroxetine 40 mg/day were both well tolerated and effective for short-term treatment of panic disorder.