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Source: Melton ST, Kirkwood CK. Anxiety Disorders. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7989670. Accessed May 26, 2012

  • Anxiety disorder characterized by unexpected and repeated episodes of panic attacks, which involve sudden intense fear that develops for no apparent reason and triggers severe physical reactions.

  • Genetic component
  • Several biochemical theories have been postulated.

  • Associated with activation of brainstem and basal ganglia regions.
  • May be abnormal activation of parahippocampal region and prefrontal cortex.
  • 5-HT may have role in development of anticipatory anxiety.

  • Affects 6 million Americans over age of 18.
  • One-year prevalence rate: 2.7%.
  • Twice as common in women as in men.

  • Family history of panic disorder
  • Stressful life events

Signs and Symptoms

  • Psychological symptoms:
    • Depersonalization
    • Derealization
    • Fear of losing control, going crazy, or dying
  • Physical symptoms:
    • Abdominal distress
    • Chest pain or discomfort
    • Chills
    • Dizziness or lightheadedness
    • Choking feeling
    • Hot flushes
    • Palpitations
    • Nausea
    • Paresthesias
    • Shortness of breath
    • Sweating
    • Tachycardia
    • Trembling
  • Symptoms usually begin as unexpected panic attacks, followed by at least 1 month of persistent concern about having another attack.
  • Symptoms of panic attack peak within 10 minutes and usually last 20–30 minutes.
  • Many patients eventually develop agoraphobia, which is avoidance of specific situations (e.g., being in crowded places) where they fear attack might occur.

Means of Confirmation and Diagnosis

  • History of recurrent, unexpected panic attacks followed by:
    • At least 1 month of concern about having another attack
    • Worry about consequences of attacks
    • Behavioral changes because of attacks
  • During attack, there must be at least four physical symptoms in addition to psychological symptoms.

  • Complete resolution of panic attacks
  • Marked reduction in anticipatory anxiety and phobias
  • Elimination of phobic avoidance
  • Resumption of normal activities

  • Cognitive behavioral therapy (CBT) may be used alone for patients who cannot or will not take medications.
  • CBT typically initiated with pharmacotherapy if agoraphobia present.
  • Educate patients to avoid:
    • Caffeine
    • Stimulants
    • Drugs of abuse

  • Figure 1: Algorithm for pharmacotherapy of panic disorder
  • Selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and benzodiazepines similarly effective; 50–80% of patients respond.
  • SSRIs preferred in elderly patients and youth; benzodiazepines second line in these patients because of potential for disinhibition.
  • Drug choices (Table 1):
    • First line: SSRIs, venlafaxine XR.
    • Second line: Alprazolam, clonazepam, clomipramine, imipramine.
    • Alternatives: Phenelzine.
  • Treat for 12–24 months before attempting discontinuation over 4–6 months.
  • Many patients require long-term therapy.
  • Antidepressants
    • SSRIs
      • Anti-panic effect requires 4 weeks; some patients require 8–12 weeks.
      • Start with low initial doses and titrate gradually to avoid stimulatory side effects (anxiety, insomnia, jitteriness, irritability).
    • Imipramine
      • Blocks panic attacks within 4 weeks in most patients; maximal improvement requires 8–12 weeks.
    • Venlafaxine XR
      • 55–60% of patients became panic-free on 75 or 150 mg.
  • Benzodiazepines
    • Second line except when rapid response essential.
    • Do not use as monotherapy in patients with history of depression or alcohol or drug abuse.
    • May use concomitantly with antidepressants in ...

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