The psychopharmacology of Panic Disorder in Singapore

Abstract

A brief review of existing treatments for Panic Disorder (PD) is provided. Pharmacotherapy remains the mainstay of treatment for PD in Singapore. In general medical settings, low potency benzodiazepines and beta-blockers are commonly prescribed. Psychiatrists are more likely to use high-potency benzodiazepines (alprazolam or clonazepam) and antidepressants (SSRIs, or Tricyclics). Other novel approaches include the use of new generation antidepressants (eg. Nefazadone, Mirtazapine or Venlafaxine) and anticonvulsants (eg. Valproate or Gabapentin). A psychopharmacological treatment algorithm for PD is suggested. An antidepressant (AD) or high-potency benzodiazepine (HPBZ) is used as first line agent, alone, or very often, in combination. The therapeutic goals are to abolish panic attacks early, decrease anticipatory anxiety, counter phobic avoidance and comprehensively treat comorbid psychopathology. HPBZ alone or in combination with AD provides rapid relief of panic symptoms within 2-4 weeks. Daytime sedation or cognitive deficits are major adverse effects. AD have a therapeutic lag phase of at least 4 weeks when used alone. Poor initial symptom relief or adverse side-effects, especially jitteriness, often leads to drug discontinuation or alternative help-seeking in the early phase of treatment. Combination of AD with HPBZ may alleviate some AD-related side-effects. Using this treatment approach, 53.3% of patients are panic-free at 4-6 weeks; 70% at 8 -10 weeks; and 83.3% are completely well at 12 weeks. Continuation treatment is strongly encouraged for a further 12 months following recovery, but compliance is often poor, especially for AD treatment; and less so for HPBZ.