Clonazepam Treatment of Panic Disorder in Patients with Recurrent Chest Pain and Normal Coronary Arteries

OBJECTIVE: To examine the efficacy of clonazepam in chest pain patients with panic disorder and normal coronary arteries. METHOD: We conducted a placebo controlled, double blind, flexible dose (1-4 mg/d), six-week trial of clonazepam. All subjects (N = 27) had current panic disorder and a negative coronary angiogram or thallium exercise tolerance test within the previous year. RESULTS: Analyses show modest improvements in the clonazepam and placebo groups over the first four weeks in both primary outcome measures. Eight of twelve (67%) clonazepam treated patients responded with reduction of panic attacks by week four to zero per week or half of initial frequency, while seven of fifteen (47%) placebo treated patients responded (not significant). When response was measured by 50 percent reduction in Hamilton Anxiety total score, however, seven of twelve (58%) clonazepam treated patients responded, while two of fifteen (14%) placebo treated patients responded, (p = .038) by Fisher's exact test. Within-subject improvements over the first four weeks were not significantly greater for the clonazepam group than for the placebo group on either outcome measure. CONCLUSIONS: These results show a generally good outcome in chest pain patients with panic disorder, and they provide suggestive evidence for the efficacy of clonazepam compared to placebo. This study points to the need for larger, well-funded treatment studies of chest pain patients with panic disorder.