Clonazepam and imipramine in the treatment of panic attacks: a double-blind comparison of efficacy and side effects.

Data from 12 patients (in two control study groups) provide preliminary results of an ongoing double-blind comparison of clonazepam and imipramine in the treatment of panic disorder. In both treatment groups, the patients' global improvement was substantial over the first few weeks and persisted over the 6-month treatment period based on assessments by the therapist and the patient; side effects were mild. Faintness was slightly more prevalent among patients on clonazepam treatment but disappeared after the first few weeks. Mild, persistent tachycardia was reported among patients receiving imipramine. No tolerance emerged, and discontinuation was successful in 2 patients from each group after 6 months of treatment. Eight patients needed continued medication (25-50 mg/day of imipramine, 0.5-2.0 mg/day of clonazepam) to maintain substantial improvement. Findings confirm earlier reports from open studies that low doses of both drugs eliminate panic attacks (about 50 mg/day for imipramine and 1.5 mg/day for clonazepam).