Three drugs are currently licensed for the treatment of panic disorder: the benzodiazepine, alprazolam; the tricyclic antidepressant, clomipramine; and, most recently, the selective serotonin reuptake inhibitor, paroxetine. Alprazolam and clomipramine are eective in the treatment of panic disorder, but are less than ideal agents due to their tolerability pro®les. An extensive clinical trial programme has been undertaken to investigate the ecacy and tolerability of paroxetine treatment in panic disorder. This article reviews the clinical evidence for the short-and long-term ecacy and tolerability of paroxetine in panic disorder, and its eect on relapse prevention and on quality of life. The results from the short-term studies indicate that paroxetine is eective in treating panic disorder (with or without agoraphobia) either alone or in combination with cognitive-behavioural therapy. The minimum eective dose is 40 mg daily. Paroxetine was equally as eective as clomipramine in reducing the frequency of panic attacks but produced an earlier improvement in symptomatology. Continued treatment with paroxetine over periods of up to 9 months provided evidence that paroxetine maintained its anti-panic eect and prevented relapse. Paroxetine was well-tolerated during both the short-and long-term studies at doses of up to 60 mg per day. # 1997 by