Imipramine (Tofranil), Serum

Imipramine is the most thoroughly studied tricyclic antidepressant for the treatment of agoraphobia and panic disorder. Several small, placebo-controlled studies and open trials have confirmed the panic-blocking effects of this drug; however, many of these studies also employed behavioral therapy, thus obscuring the relative contribution of imipramine. A recent placebo-controlled, dose-response study confirmed that imipramine alone has significant antipanic and antiphobic effects. The best response was obtained at a dosage of 150−200 mg/day (mean, 185 mg/day). Most other studies also emphasize titrating the dosage to establish plasma concentrations within the range used for the treatment of depression; however, some patients may respond to doses <100 mg/day. Imipramine also has been given with high-potency benzodiazepines for panic disorder.