Pharmacotherapy of Anxiety Disorders

Pharmacotherapy of Anxiety Disorders

Pharmacotherapy of Anxiety Disorders

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Anxiolytics Overview - Pill Power Intro

  • Major Anxiolytic Classes:
    • SSRIs & SNRIs (Often first-line)
    • Benzodiazepines (BZDs) (Rapid relief, short-term)
    • Buspirone (Non-sedating, delayed onset)
    • Beta-blockers (Performance anxiety, e.g., Propranolol)
    • TCAs & MAOIs (Reserved due to side effects/interactions)
  • Indications for Pharmacotherapy:
    • Moderate to severe symptoms, functional impairment.
    • Patient preference or inadequate psychotherapy response.
  • General Principles:
    • Start low, go slow.
    • Adequate trial: 4-8 weeks at therapeutic dose.
    • Taper gradually on discontinuation to prevent withdrawal.

⭐ SSRIs are generally first-line for most anxiety disorders due to better tolerability and safety profile.

SSRIs & SNRIs - Serotonin Soothers

  • MOA: SSRIs selectively inhibit 5-HT reuptake; SNRIs inhibit 5-HT & NE reuptake.
  • Examples (Anxiety Doses):
    • SSRIs: Fluoxetine (20-60mg), Sertraline (50-200mg), Paroxetine (20-50mg), Escitalopram (10-20mg).
    • SNRIs: Venlafaxine XR (75-225mg), Duloxetine (60-120mg).
  • Uses: First-line for GAD, Panic Disorder, Social Anxiety Disorder, PTSD, OCD.
  • Side Effects: GI upset, sexual dysfunction, initial ↑anxiety, sleep issues. Serotonin Syndrome (agitation, hyperthermia, hyperreflexia).
  • Key Notes:
    • Therapeutic effect: 2-4 weeks (up to 6-8).
    • Discontinuation 📌 FINISH: Flu-like symptoms, Insomnia, Nausea, Imbalance, Sensory disturbances, Hyperarousal.

⭐ SSRIs are first-line for most anxiety disorders due to better tolerability. Antidepressant Classes, Actions, Side Effects

Benzodiazepines - Rapid Relaxers

  • MOA: Positive allosteric modulators of GABA-A receptors; ↑ frequency of $Cl^-$ channel opening, enhancing GABAergic inhibition.
  • Classification & Examples:
    • Short-acting: Midazolam, Triazolam.
    • Intermediate-acting: Alprazolam, Lorazepam, Oxazepam, Temazepam. (📌 Mnemonic 'LOT': Lorazepam, Oxazepam, Temazepam - safer in liver disease/elderly).
    • Long-acting: Diazepam, Clonazepam, Chlordiazepoxide.
  • Indications: Acute anxiety, panic attacks, insomnia (short-term), procedural sedation, alcohol withdrawal, status epilepticus.
  • Adverse Effects: Sedation, drowsiness, psychomotor impairment, anterograde amnesia, respiratory depression (⚠️ risk with opioids), dependence, tolerance, withdrawal syndrome.
  • Antidote: Flumazenil.

⭐ Flumazenil reverses BZD overdose but must be used cautiously in chronic users due to risk of precipitating seizures. Benzodiazepine action on GABA-A receptor

Other Anxiolytics - Backup Brigade

  • Buspirone: 5-HT1A partial agonist, D2 antagonist. Delayed onset (2-4 weeks). No dependence/withdrawal. For GAD; not panic disorder.

    ⭐ Buspirone has a delayed onset of anxiolytic action, typically 2-4 weeks, and is not effective for acute anxiety or panic attacks.

  • Beta-blockers (e.g., Propranolol): For performance anxiety (social phobia), managing peripheral somatic symptoms (tremor, tachycardia). Propranolol 10-40 mg prior to event.
  • Pregabalin: Binds to $\alpha2\delta$ subunit of voltage-gated Ca$^{2+}$ channels. Anxiolytic in GAD, faster onset than SSRIs. Potential for misuse.
  • Antihistamines (e.g., Hydroxyzine): Sedative/anxiolytic via H1 antagonism. Short-term anxiety, insomnia.
  • TCAs & MAOIs: Imipramine (panic), Clomipramine (OCD), Phenelzine. Use limited by side effects/dietary restrictions (MAOIs).

Anxiety Rx Algorithms - Smart Steps

  • Core Strategy: SSRIs/SNRIs are first-line for GAD, Panic Disorder, SAD, PTSD, OCD.
  • Benzodiazepines (BZDs) for initial severe symptoms (short-term bridge).
  • GAD/Panic Disorder Flow:
  • OCD: Higher SSRI doses often needed; Clomipramine is effective.
  • PTSD: Prazosin for nightmares.
  • Duration: Maintain treatment 6-12 months post-remission before slow taper.

⭐ For most anxiety disorders, SSRIs or SNRIs are the initial pharmacotherapy of choice due to their efficacy and tolerability profile.

High‑Yield Points - ⚡ Biggest Takeaways

  • SSRIs (Escitalopram, Sertraline) are first-line for GAD, panic, social anxiety, and PTSD.
  • SNRIs (Venlafaxine, Duloxetine) are also first-line, especially with comorbid pain or if SSRIs fail.
  • Benzodiazepines offer rapid relief but are for short-term/SOS use only due to high dependence risk.
  • Buspirone is a non-BZD anxiolytic for GAD; delayed onset (2-4 weeks), no abuse potential.
  • Beta-blockers (Propranolol) manage performance anxiety by reducing peripheral autonomic symptoms.
  • TCAs/MAOIs are older agents, typically third-line due to side effects and interactions_._

Practice Questions: Pharmacotherapy of Anxiety Disorders

Test your understanding with these related questions

An SSRI antidepressant, such as fluoxetine, will be prescribed for an adult patient. You should advise him or her that two of the most likely side effects or adverse responses that may eventually occur at therapeutic blood levels are which of the following?

1 of 5

Flashcards: Pharmacotherapy of Anxiety Disorders

1/10

What neurotransmitters are decreased in anxiety? _____ and GABA

TAP TO REVEAL ANSWER

What neurotransmitters are decreased in anxiety? _____ and GABA

Serotonin

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