Hydroxyzine (Vistaril, Atarax) is a first-generation H1 antihistamine used as an anxiolytic, antipruritic (anti-itch), and pre-procedural sedative. It works by blocking histamine H1 receptors and muscarinic receptors in the CNS, producing rapid sedation within 15–30 minutes. Common side effects include sedation, dry mouth, and dizziness. Notably, hydroxyzine is not a controlled substance and carries no significant addiction potential, making it a non-habit-forming alternative to benzodiazepines for anxiety; its primary active metabolite is cetirizine (Zyrtec).
Hydroxyzine
Uses & FDA Indications
Hydroxyzine occupies a unique niche as a non-controlled anxiolytic with a long track record, making it particularly valuable when benzodiazepine use is contraindicated or undesirable — in patients with substance use disorder histories, those at risk for dependence, or settings where controlled substances are restricted.
FDA-approved indications include: short-term management of anxiety and tension, pruritus (itching) due to allergic conditions such as chronic urticaria and atopic or contact dermatitis, and pre- and post-operative sedation as well as pre-procedure anxiolysis. It is also used for nausea and vomiting management in some clinical contexts.
Off-label uses include insomnia (where its sedating properties are exploited), alcohol withdrawal adjunct, and nausea in outpatient settings. Its rapid onset distinguishes it from antidepressants for situational anxiety management.
How It Works
Hydroxyzine is a first-generation H1 antihistamine — it competitively and reversibly blocks histamine H1 receptors. Unlike second-generation antihistamines (cetirizine, loratadine, fexofenadine), it crosses the blood-brain barrier readily, producing pronounced CNS depression that underlies both its anxiolytic and sedative properties.
Beyond H1 antagonism, hydroxyzine also exhibits anticholinergic activity (contributing to dry mouth, urinary retention, constipation), mild serotonin antagonism, and mild alpha-adrenergic blockade. The combined CNS depressant and anticholinergic profile explains both its therapeutic sedation and its side effect burden.
A pharmacologically important fact: hydroxyzine is metabolized to cetirizine (Zyrtec), its primary active metabolite. Taking hydroxyzine and cetirizine simultaneously provides no additive benefit while increasing antihistamine side effects — patients should not take both concurrently.
BEERS CRITERIA: The American Geriatrics Society Beers Criteria classifies first-generation antihistamines including hydroxyzine as potentially inappropriate medications in adults 65 years and older due to their potent anticholinergic effects, which increase the risk of confusion, constipation, urinary retention, dry mouth, falls, and cognitive impairment in elderly patients.
Side Effects
Common
- Significant sedation — the most common and prominent effect; impairs driving and operating machinery. More pronounced than with second-generation antihistamines.
- Dry mouth — anticholinergic effect; often persistent
- Constipation — anticholinergic; increases with higher doses
- Blurred vision — anticholinergic effect on ciliary muscle
- Urinary retention — anticholinergic; particularly concerning in men with BPH
- Dizziness, headache
Serious
- QT prolongation — hydroxyzine can prolong the cardiac QT interval, increasing risk of serious ventricular arrhythmias (torsades de pointes) particularly when combined with other QT-prolonging agents or in patients with underlying cardiac conditions.
- Anticholinergic toxicity — in overdose or with concurrent anticholinergics: confusion, agitation, hyperthermia, urinary retention, tachycardia. Particularly dangerous in elderly.
Drug Interactions
| Drug / Class | Interaction | Clinical Significance |
|---|---|---|
| CNS Depressants (opioids, benzodiazepines, alcohol, sleep aids) | Additive CNS depression — excessive sedation, respiratory depression risk, impaired psychomotor function. | High — use with caution; reduce doses if combined; counsel on driving impairment |
| Anticholinergic Drugs (TCAs, atropine, scopolamine, bladder agents) | Additive anticholinergic effects — dry mouth, constipation, urinary retention, confusion, tachycardia. Particularly dangerous in elderly. | Moderate-High — avoid or closely monitor anticholinergic burden |
| QT-Prolonging Drugs (antipsychotics, fluoroquinolones, ondansetron, methadone) | Additive QTc prolongation raises risk of torsades de pointes ventricular arrhythmia. | Moderate-High — review QTc risk with cardiologist if multiple QT drugs required |
| Cetirizine (Zyrtec) | Hydroxyzine is metabolized to cetirizine. Taking both simultaneously increases antihistamine exposure without additional benefit. | Moderate — avoid concurrent use; pharmacokinetic redundancy |
Warnings & Contraindications
Contraindications
- Hypersensitivity to hydroxyzine or cetirizine
- Early pregnancy — teratogenic risk; avoid in first trimester
- Prolonged QT interval at baseline
QTc Prolongation
Hydroxyzine has been shown to prolong the cardiac QT interval in a dose-dependent manner. Patients with risk factors for QT prolongation — electrolyte abnormalities (hypokalemia, hypomagnesemia), bradycardia, congenital long QT syndrome, or concurrent use of other QT-prolonging agents — require more careful assessment before use. A baseline ECG is warranted in high-risk patients.
Use in Elderly
The American Geriatrics Society Beers Criteria specifically flags hydroxyzine and all first-generation antihistamines as potentially inappropriate in patients 65 and older. Anticholinergic medications are a leading cause of medication-related adverse events in elderly patients: confusion, falls, urinary retention, delirium, and worsening cognitive function. Alternatives with better safety profiles in elderly populations should be prioritized.
Check for QT prolongation risk or other interactions with hydroxyzine.
Check Drug Interactions →Frequently Asked Questions
Is hydroxyzine a controlled substance?
No. Hydroxyzine is not scheduled under the DEA Controlled Substances Act and is not a controlled substance. This is one of its key advantages over benzodiazepines like alprazolam or clonazepam for managing anxiety — it carries no risk of physical dependence or scheduled-drug regulatory requirements. Prescribers often use it as a first-line or alternative anxiolytic specifically because of this non-controlled status, particularly in patients with substance use disorder histories.
Does hydroxyzine work immediately for anxiety?
Yes — hydroxyzine works relatively quickly compared to antidepressants. It is absorbed rapidly after oral administration, with onset of anxiolytic and sedative effects occurring within 15–30 minutes and peak effects at 1–2 hours. This rapid onset makes it suitable for situational anxiety (pre-procedure, acute anxiety episodes) rather than as a daily long-term treatment. Unlike SSRIs or SNRIs, there is no multi-week latency before effects are felt.
Is hydroxyzine addictive?
Hydroxyzine does not cause physical dependence or addiction in the way benzodiazepines do. It does not act on GABA-A receptors or produce tolerance and withdrawal in the clinical sense. However, some patients experience rebound anxiety or disrupted sleep when stopping after prolonged use, which is different from true physical dependence. Gradual tapering is still reasonable after extended use, but the risk profile is fundamentally different from — and far safer than — scheduled anxiolytics.