Plasma levels of tricyclic antidepressants in panic disorder.

Five patients with panic disorder were placed on low doses of imipramine. All patients had shown dramatic improvement after three weeks of treatment, when plasma levels of imipramine and desipramine were measured. Plasma levels corresponded to the low doses being administered. This result implies that the mechanism of action of tricyclic antidepressants is different in patients with panic disorder than in patients with depressive disorder.