A 28-year-old man with a 5-year history of specific phobia (fear of flying) is seeking pharmacological treatment. He experiences severe anxiety only when anticipating or boarding flights, with no baseline anxiety between episodes. Which is the drug of choice for this condition?

Explanation

## Pharmacotherapy of Specific Phobia **Key Point:** Specific phobia is situational anxiety triggered by a discrete object or event. Unlike panic disorder or generalized anxiety disorder, it does NOT require continuous pharmacotherapy; instead, as-needed beta-blockers are preferred for acute situational anxiety. ### Rationale for Beta-Blocker Use Propranolol (or other non-selective beta-blockers like atenolol) is the drug of choice because: - **Mechanism:** Blocks peripheral β-adrenergic receptors, reducing somatic symptoms (tachycardia, tremor, sweating) that amplify fear perception - **Timing:** Taken 30–60 minutes before the feared situation (e.g., before boarding a flight) - **Efficacy:** Effective for performance anxiety and situational phobia; reduces the physiological feedback loop that reinforces anxiety - **No dependence:** Unlike benzodiazepines, beta-blockers carry no addiction risk ### Dosing - **Propranolol:** 20–40 mg PO 30–60 minutes before exposure - **Atenolol:** 25–50 mg PO 1–2 hours before exposure ### Why Not Continuous Medication? Specific phobia is **episodic and situational**. The patient has no baseline anxiety, so continuous SSRIs or benzodiazepines are unnecessary and expose him to unnecessary side effects. **High-Yield:** The distinction is critical: - **Panic Disorder / GAD:** Continuous SSRI - **Specific Phobia (situational):** As-needed beta-blocker OR cognitive-behavioral therapy (CBT) - **Social Anxiety Disorder:** Continuous SSRI or SNRI ### Comparison of Agents in Specific Phobia | Agent | Use | Rationale | |-------|-----|----------| | **Propranolol (as-needed)** | ✓ First-line | Blocks somatic symptoms; no dependence; situational use | | **Paroxetine (continuous)** | ✗ Overkill | Indicated for panic/GAD; unnecessary daily dosing for episodic phobia | | **Diazepam (as-needed)** | ✗ Avoid | Risk of dependence; less specific than beta-blocker for somatic symptoms | | **Buspiron** | ✗ Ineffective | No role in acute anxiety or phobia | **Clinical Pearl:** Cognitive-behavioral therapy (CBT) with exposure therapy is the gold standard for specific phobia and should be offered alongside or instead of medication. Beta-blockers are a bridge during initial exposures. **Mnemonic:** **BETA-SIT** — BETa-blockers for Acute Situational anxiety; Ideal for Tachycardia, Tremor. **Warning:** Do not confuse specific phobia with panic disorder. Panic disorder requires continuous SSRI; specific phobia requires situational beta-blocker. [cite:Harrison 21e Ch 397; DSM-5]