The Efficacy and Safety of Clonazepam in Patients with Anxiety Disorder Taking Newer Antidepressants: A Multicenter Naturalistic Study.

OBJECTIVE This study compared the efficacy and tolerability of clonazepam with other benzodiazepines in patients with anxiety disorders. METHODS Inclusion criteria were as follows: age >20 years, diagnosis of anxiety disorder according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition, text revision (DSM-IV-TR) criteria, taking only one type of antidepressant, and prescribed one of three oral benzodiazepines (alprazolam, clonazepam, or lorazepam). At baseline and week 6, clinical benefit was evaluated using the Clinical Global Impression-Severity Scale (CGI-S), Clinical Global Impression-Anxiety Scale (CGI-anxiety), and Clinical Global Impression-Sleep Scale (CGI-sleep). RESULTS Among 180 patients, no differences in demographic characteristics among the three benzodiazepine groups were noted. After six weeks of treatment, all benzodiazepine groups showed significant improvements in CGI-S, CGI-anxiety, and CGI-sleep scores (p<0.001). There were no differences in mean changes in CGI-S, CGI-anxiety and CGI-sleep among the three benzodiazepine groups. The incidence of side effects was significantly lower in the clonazepam group than with the other benzodiazepines. The incidences of adverse events for the clonazepam, alprazolam, and lorazepam groups were 26.7% (n=20), 48.4% (n=31), and 43.9% (n=18), respectively. CONCLUSION The present study suggests that clonazepam is as efficacious as other benzodiazepines for the treatment of various anxiety disorders. Furthermore, the safety profile of clonazepam was superior to the other benzodiazepines in this study.