The goals are complete resolution of panic attacks, marked reduction in anticipatory anxiety, elimination of phobic avoidance, and resumption of normal activities.
SSRIs( selective serotonin re-uptake inhibitors) are first-line agents for panic disorder. Most patients without agoraphobia improve with pharmacotherapy alone, but if agoraphobia is present, Cognitive Behavioral Therapy( CBT )typically is initiated concurrently. Patients treated with CBT are less likely to relapse than those treated with imipramine alone. For patients who cannot or will not take medications, CBT alone is indicated.
Educate patient to avoid caffeine, nicotine, alcohol, drugs of abuse, and stimulants. If pharmacotherapy is used, antidepressants, especially the SSRIs, are preferred in elderly patients and youth. The benzodiazepines are second line in these patients because of potential problems with disinhibition.
Usually patients are treated for 12 to 24 months before discontinuation is attempted over 4 to 6 months. Many patients require long-term therapy. Single weekly doses of fluoxetine have been used for maintenance.
Stimulatory side effects (eg, anxiety, insomnia, jitteriness) can occur in Tricyclic antidepressants (TCA)– and SSRI-treated patients. This may hinder compliance and dose escalation. Low initial doses and gradual dose titration may eliminate these effects.
Imipramine blocks panic attacks within 4 weeks in 75% of patients, but reducing anticipatory anxiety and phobic avoidance requires 8 to 12 weeks. 25% of panic disorder patients discontinue TCAs because of side effects.
SSRIs eliminate panic attacks in 60% to 80% of patients within about 4 weeks, but some patients require 8 to 12 weeks.
Approximately 54% to 60% of patients became panic-free on extended-release venlafaxine, 75 mg or 150 mg.
Benzodiazepines are second-line agents for panic disorder except when rapid response is essential. Avoid benzodiazepine monotherapy in patients with panic disorder who are depressed or have a history of depression. Avoid benzodiazepines in patients with a history of alcohol or drug abuse. They are often used concomitantly with antidepressants in the first 4 to 6 weeks to achieve a more rapid antipanic response.
Relapse rates of 50% or higher are common despite slow drug tapering.
Alprazolam and clonazepam are the most frequently used benzodiazepines. Therapeutic response typically occurs within 1 to 2 weeks. With alprazolam, there may be breakthrough symptoms between doses. The use of extended-release alprazolam or clonazepam avoids this problem.
Dosing and Administration
The starting dose of clonazepam is 0.25 mg twice daily, with a dose increase to 1 mg by the third day. Increases by 0.25 to 0.5 mg every 3 days to 4 mg/day can be made if needed.
The starting dose of alprazolam is 0.25 to 0.5 mg three times daily (or 0.5 mg once daily of extended-release alprazolam), slowly increasing over several weeks as needed. Most patients require 3 to 6 mg/day.