Hydroxyzine

ID: hydroxyzine

Aliases: hydroxyzine hydrochloride, hydroxyzine pamoate, Atarax, Vistaril

Type: compound

Route/form: oral prescription tablet/capsule/syrup or injectable depending product

Status: approved_or_labelled

Evidence level: approved / labelled

Best data tier: approved label + human controlled/review

Support scope: human, review/regulatory

Source types: evidence_report, human_association_and_preclinical, human_rct, label, regulatory_safety, safety_review, systematic_review

Linked sources: 7

Broad outcomes: Brain / mood / sleep, Cardiovascular / lipids / blood pressure

Reading note: These are curation notes anchored to linked sources, not a clinical recommendation or protocol.

Targets / mechanism

• H1 histamine receptor antagonism
• sedation/anxiolysis
• CNS depressant potentiation

Optimization domains

• anxiety
• allergy
• sleep
• insomnia
• sedation
• cardiovascular

Research basis

• Hydroxyzine has labelled anxiety/sedation/allergy uses plus randomized and Cochrane-reviewed GAD evidence, making it more evidence-backed for anxiety than many OTC sedatives.
• It is relevant to sleep-stack conversations because sedation may help initiation without benzodiazepine/GABA-A agonism.
• The strongest optimization framing is short-term anxiety/sedation under awareness of QT and impairment risks.

Limits, risks, and missing evidence

• Sedation does not equal durable sleep maintenance, and Cochrane-level evidence still has limitations.
• As a first-generation antihistamine with anticholinergic effects, hydroxyzine should inherit older-adult anticholinergic-burden cautions, including delirium/falls and observational dementia-risk signals with cumulative exposure.
• QT prolongation/TdP warnings, anticholinergic effects, next-day impairment, and additive CNS depression are central constraints.
• Combining with trazodone, clomipramine, diphenhydramine, beta-blockers, clonidine, or other QT-risk drugs can be a bad risk trade.

Risk flags

• approved drug
• sedating
• qt risk
• anticholinergic
• cumulative anticholinergic burden
• older adult high risk
• dementia association observational
• next day impairment
• stack interactions

Linked papers, labels, and reviews

1. DailyMed label: hydroxyzine hydrochloride tablet
   label / dailymed_hydroxyzine_label
   Hydroxyzine label for anxiety/sedation/allergy contexts; warns about CNS depressant potentiation and QT prolongation/TdP reports.
2. Hydroxyzine: risk of QT interval prolongation and Torsade de Pointes
   regulatory_safety / govuk_hydroxyzine_qt_warning_2015
   UK drug-safety update summarizing European review and QT/TdP risk-minimization recommendations for hydroxyzine.
3. Association of anxiolytic drugs with Torsade de Pointes: a pharmacovigilance study of the FDA Adverse Event Reporting System
   safety_review / pmc_anxiolytics_torsade_faers_2024
   FAERS pharmacovigilance analysis including hydroxyzine among anxiolytic drugs with TdP-related reports.
4. Efficacy and safety of hydroxyzine in generalized anxiety disorder: a 3-month double-blind study
   human_rct / pubmed_hydroxyzine_gad_2002
   Randomized double-blind placebo/active-comparator GAD trial; useful for anxiety claims distinct from sleep-stack anecdotes.
5. Hydroxyzine for generalised anxiety disorder
   systematic_review / pubmed_hydroxyzine_gad_cochrane_2010
   Cochrane review summarizing hydroxyzine evidence for GAD and limitations of the trial base.
6. American Geriatrics Society 2023 updated AGS Beers Criteria for potentially inappropriate medication use in older adults
   evidence_report / pubmed_ags_beers_criteria_2023
   Geriatric prescribing criteria covering strongly anticholinergic drugs, including first-generation antihistamines and selected antidepressants; useful for older-adult delirium, falls, cumulative anticholinergic burden, and dementia-risk framing.
7. Anticholinergic Drug Exposure and the Risk of Dementia: A Nested Case-Control Study
   human_association_and_preclinical / pubmed_anticholinergic_dementia_coupland_2019
   Large nested case-control study; supports cumulative anticholinergic burden as a dementia-risk signal while requiring class-specific and confounding-aware interpretation.