Panic disorder is becoming better recognised and understood as a chronic, debilitating but treatable condition.
Drug treatment options shown by adequate research to be beneficial in this condition include mainly the
benzodiazepine alprazolam, the
tricyclic antidepressants (TCAs)
imipramine and
clomipramine, the
monoamine oxidase inhibitor (MAOI)
phenelzine, and the newer
selective serotonin reuptake inhibitors (
SSRIs)
fluvoxamine and
paroxetine.
Alprazolam, although approved for use in
panic disorder in the US and very widely used, is associated with a risk of dependence and withdrawal syndromes. Given that depression frequently occurs as a comorbid condition with
panic disorder the use of
antidepressants is a logical choice. Among the
antidepressants, MAOIs are little-used in
panic disorder, mainly because of their potential for precipitating
hypertensive crises if
tyramine is ingested. TCAs are widely used and are effective but they are associated with initial activation, or 'jitteriness', have a 4-6-week time lag before onset of beneficial effect and produce troublesome side effects in a high proportion of patients, particularly during long-term use. TCAs are also cardiotoxic in overdosage, and
panic disorder patients with comorbid depression are at high risk of attempted suicide.
Serotonin dysregulation has been implicated in the pathogenesis of
anxiety disorders in general, and
panic disorder in particular. Among the TCAs, those with an effect on
serotonin reuptake are most effective in
panic disorder.
SSRIs are specifically active on
serotonin reuptake and do not have
anticholinergic effects or act on the noradrenergic system. There is a clear pharmacological rationale for believing that
SSRIs should be as effective as TCAs in
panic disorder and better tolerated. Accumulating clinical research evidence supports this hypothesis. Further comparative studies with standard agents and additional long-term studies to support the initial long-term data with
paroxetine are needed to confirm
SSRIs as
drug treatment of choice in
panic disorder.