Hydroxyzine (Vistaril, Atarax)

Class

First-generation antihistamine

Mechanism

Antagonizes H1 histamine receptors and exhibits anticholinergic effects, contributing to sedation and anxiolysis

FDA-Approved Use

Anxiety, pruritus, preoperative sedation

Off-Label Use

Short-term management of insomnia, acute agitation, adjunctive anxiety treatment in substance use disorders or when benzodiazepines are contraindicated

Formulation

Oral tablets, capsules, syrup, and injectable forms

Titration

25–50 mg p.o. every 4–6 hours PRN for agitation or anxiety; lower doses (25–50 mg) at bedtime for insomnia

Dose Range

25–100 mg/day in single or divided doses

Kinetics

Metabolized in the liver, half-life approximately 20 hours; onset within 15–30 minutes after oral administration

Common AEs

Sedation, dry mouth, dizziness, blurred vision, cognitive dulling

Serious/Rare AEs

Tolerance may develop with prolonged use

Monitoring

Monitor sedation and cognitive effects, especially with prolonged use or in vulnerable populations

Black Box Warning

None

Considerations

Hydroxyzine is generally avoided in elderly individuals, patients with dementia, or those recovering from traumatic brain injury (TBI) due to increased risk of sedation, falls, and confusion. It may be helpful in managing anxiety or agitation in younger patients with developmental disorders or substance use concerns.