Hydroxyzine (Vistaril, Atarax)
Class: First-generation antihistamine
Indications: Anxiety, insomnia, nausea, pruritus (itching), and allergic reactions
Brand Names: Vistaril (capsule), Atarax (tablet)
Mechanism of Action:
Hydroxyzine is a histamine H₁ receptor antagonist that crosses the blood-brain barrier and exerts central nervous system (CNS) depressant effects. It blocks H₁ receptors in the brain, which contributes to its sedative and anxiolytic properties.
Additionally, Hydroxyzine has:
Clinical Benefits:
Prevalence of Side Effects:
Side Effect & Prevalence
Sedation/drowsiness13–30%
Dry mouth1–15%
Headache<2%
Dizziness<2%
Blurred vision<2%
Constipation or urinary retention<2%
Confusion (in older adults)Rare, but increased risk in elderly due to anticholinergic burden
Hydroxyzine is generally well-tolerated, but due to its sedating and anticholinergic effects, it should be used cautiously in older adults (risk of falls, confusion, or cognitive impairment).
Onset and Duration:
Indications: Anxiety, insomnia, nausea, pruritus (itching), and allergic reactions
Brand Names: Vistaril (capsule), Atarax (tablet)
Mechanism of Action:
Hydroxyzine is a histamine H₁ receptor antagonist that crosses the blood-brain barrier and exerts central nervous system (CNS) depressant effects. It blocks H₁ receptors in the brain, which contributes to its sedative and anxiolytic properties.
Additionally, Hydroxyzine has:
- Anticholinergic effects, which contribute to sedation
- Weak antagonistic effects on 5-HT₂ (serotonin) receptors, which may enhance anxiolytic effects
- No significant activity at benzodiazepine or GABA receptors, making it non-habit forming
Clinical Benefits:
- Anxiety Relief: Effective for short-term management of Generalized Anxiety Disorder (GAD) or situational anxiety. Often used as an alternative to benzodiazepines.
- Sleep Aid: Promotes sleep due to sedative effects, especially for patients with anxiety-related insomnia.
- Non-habit forming: No risk of physical dependence or tolerance.
- Useful in patients with substance use concerns or where benzodiazepines are contraindicated.
- Also treats: Nausea, itching, and allergic reactions due to antihistaminic properties.
Prevalence of Side Effects:
Side Effect & Prevalence
Sedation/drowsiness13–30%
Dry mouth1–15%
Headache<2%
Dizziness<2%
Blurred vision<2%
Constipation or urinary retention<2%
Confusion (in older adults)Rare, but increased risk in elderly due to anticholinergic burden
Hydroxyzine is generally well-tolerated, but due to its sedating and anticholinergic effects, it should be used cautiously in older adults (risk of falls, confusion, or cognitive impairment).
Onset and Duration:
- Onset of Action: 15–30 minutes
- Peak Effect: ~2 hours
- Duration: 4–6 hours (shorter for sleep aid purposes)