hydroxyzine

General Information

Hydroxyzine is a first-generation antihistamine used for anxiety symptoms, pruritus, and sedation. In psychiatric practice it is often used short-term as a PRN calming agent when clinicians want to avoid benzodiazepines.

Two oral salt forms are used clinically (hydroxyzine hydrochloride and hydroxyzine pamoate). Both are sedating and carry anticholinergic and fall-risk liabilities, especially in older adults.

Because it is anticholinergic and sedating, hydroxyzine can worsen confusion, constipation, and urinary retention—especially in older adults; QT risk also limits use and makes medication reconciliation and electrolyte assessment important.

Hydroxyzine is often used as a short-term PRN bridge rather than a chronic daily medication; if anxiety symptoms are frequent, plans often shift toward primary therapy (psychotherapy, SSRIs/SNRIs) rather than escalating PRN sedatives.

The hydroxyzine compare view, the hydroxyzine evidence feed, and the hydroxyzine print page can support side-by-side review and counseling when aligning short-term calming strategies with longer-term anxiety and sleep plans.

QT risk and anticholinergic burden are key limiters; hydroxyzine is generally treated as a time-limited adjunct while primary anxiety therapies take effect. It is widely available and often refilled “by momentum,” so a documented stop plan and reassessment within days to weeks are common when doses are being used frequently.

Mechanism of Action

Refer to the Glossary entry on Neurotransmitters for background on receptor systems involved in serious mental illness.

H1 receptor antagonism reduces allergic symptoms and produces sedation.

Anticholinergic and antiemetic properties contribute to calming and nausea relief.

• H1 antagonism (sedation).
• Anticholinergic activity (dry mouth, constipation, urinary retention).

Metabolism and Pharmacokinetics

• Hepatic metabolism; clinical duration can outlast perceived half-life due to sedation and anticholinergic effects.
• Caution is warranted in older adults and those with impaired clearance; lower starting doses and reassessment of next-day impairment are common.
• Sedation can persist beyond the perceived dosing window; driving safety and daytime functioning are often reassessed after initiation or dose increases.

Dosing and Administration

• Anxiety/acute distress (off label patterns vary): 25–50 mg every 6–8 hours as needed; consider 10–25 mg starting doses in older adults or high fall risk.
• Insomnia symptoms (off label): 25–50 mg at bedtime as needed; nightly indefinite use is generally avoided.
• Combining with other sedatives can increase impairment; follow-up within days to weeks helps prevent automatic refills.
• If daytime use is considered, counseling about driving impairment and lowest-effective dosing is common; many patients do better with bedtime-only use.

Monitoring & Labs

• Sedation, falls, and driving impairment are often reassessed after initiation and during dose changes—especially in older adults.
• Anticholinergic effects (constipation, urinary retention, confusion) are commonly monitored; total anticholinergic burden is minimized when possible.
• QT risk: QT-prolonging co-medications and electrolytes are typically reviewed, and baseline ECGs are often considered when risk factors stack.
• If use becomes frequent, the diagnosis is often revisited and plans may shift toward long-term anxiety treatment rather than continued PRN escalation.

Sources: FDA/DailyMed labels; EMA QT communication; guideline statements.

Adverse Effects

Interactions

• Additive CNS depression with alcohol, opioids, benzodiazepines, and sedating antipsychotics.
• Additive QT risk with other QT-prolonging agents; ECG monitoring is often considered when risk factors stack.
• Additive anticholinergic burden with low-potency antipsychotics and bladder antimuscarinics increases delirium risk.
• Stacking QT-risk agents (certain antipsychotics, methadone, antiarrhythmics) increases risk; minimizing combinations is preferred when feasible. When combinations occur, ECG monitoring and electrolyte correction are commonly considered.

Other Useful Information

• CBT-based approaches for insomnia and psychotherapy/SSRI/SNRI strategies for persistent anxiety are typically emphasized, with hydroxyzine used as a short-term bridge.
• Frequent reassessment and a documented stop plan help prevent refill momentum; chronic daily use in older adults is generally avoided when possible.
• If QT risk factors exist (cardiac disease, electrolyte issues, multiple QT meds), baseline ECGs are often considered and alternatives may be preferred when feasible.
• Short prescriptions with planned follow-up and a documented stop plan can reduce automatic refills; when anxiety remains frequent, the focus often shifts to primary therapy rather than escalating PRN sedatives.

References

1. Hydroxyzine hydrochloride prescribing information — DailyMed (2025)
2. Hydroxyzine pamoate prescribing information — DailyMed (2025)
3. Evidence Based Pharmacological Treatment OF Anxiety Disorders — Depression and Anxiety (2014)
4. NEW Restrictions TO Minimise THE Risks OF Effects ON Heart Rhythm With Hydroxyzine Containing Medicines — European Medicines Agency (2015)
5. Guidelines FOR THE Pharmacological Treatment OF Anxiety Disorders, Obsessive Compulsive Disorder AND Posttraumatic Stress Disorder IN Primary Care — International Journal of Psychiatry in Clinical Practice (2012)