Paroxetine has been shown to be effective in
panic disorder in three 10- to 12-week studies. This trial studied the longer term effects of
paroxetine in patients with DSM-III-R defined
panic disorder. Patients who satisfactorily completed a 12-week, double-blind, placebo-controlled study of
paroxetine and
clomipramine could choose to continue receiving their randomized treatment for a further 36 weeks. Efficacy assessments included the daily
panic attack diary, the Clinical Global Impression Scale, the Hamilton Anxiety Rating Scale, the Marks Sheehan
Phobia Scale and the Sheehan Disability Scale. In total, 176 patients were included in the intention-to-treat population. The number of full
panic attacks decreased in all three groups during the 12-week study, and improvements continued with long-term
therapy.
Paroxetine was statistically significantly more effective than placebo throughout the long-term study with respect to reduction from baseline of full
panic attacks, and at the end of treatment with respect to the proportion of patients who eventually experienced no
panic attacks. There were no significant differences between
paroxetine and
clomipramine. The proportion of patients who withdrew from the study due to adverse effects was greater in the
clomipramine group (19%) than in either the
paroxetine group (7%) or the placebo group (9%).
Paroxetine was significantly more effective than placebo and as effective as (but better tolerated than)
clomipramine in the long-term treatment of
panic disorder. Not only was efficacy maintained, but continued improvement was also seen, indicating the importance of long-term treatment in patients with
panic disorder.