HalfLifeDBEvidence before certainty.

Hydroxyzine evidence profile

The current human-facing label provides clinical context, but the pharmacokinetic paper attached to this draft studied exercised horses.

Category: antihistamine · Updated: August 7, 2026

Sources and model notes are maintained by . This page is educational, not clinical guidance. Corrections: admin@halflifedb.co.

Model statusNo curve publishedCurrent sources do not support one defensible human input
Evidence boundarySource note onlyNo animal, forensic, mixture, or proxy value is presented as a human half-life
Model scopeNot modeledThe profile explains what the available records can and cannot establish
References3Linked studies, labels, reviews, or identity records described below

Hydroxyzine: evidence and interpretation notes

Why HalfLifeDB does not plot Hydroxyzine

The current human-facing label provides clinical context, but the pharmacokinetic paper attached to this draft studied exercised horses. A veterinary estimate is not carried into the public human model.

What each source contributes

  • DailyMed: HYDROXYZINE PAMOATE CAPSULE [COUPLER LLC]. This product label adds formulation-specific pharmacokinetic context and does not represent every route or product.
  • PubChem: Hydroxyzine. This identity record confirms names and compound identity and does not supply a human half-life.
  • Pharmacokinetics of hydroxyzine and cetirizine following oral administration of hydroxyzine to exercised Thoroughbred horses. This preclinical study documents species-specific disposition or assay work and is not translated into a typical human estimate.

For Hydroxyzine, the decision to withhold a curve turns on the limits visible in DailyMed: HYDROXYZINE PAMOATE CAPSULE [COUPLER LLC]. This product label adds formulation-specific pharmacokinetic context, but it does not represent every route or product.

What evidence would change the page

A defensible Hydroxyzine curve would require repeated human samples and a reported estimate for Hydroxyzine itself, rather than an inference from species, cases, related compounds, or class behavior. The current key record, DailyMed: HYDROXYZINE PAMOATE CAPSULE [COUPLER LLC], answers a narrower question.

InterpretationCategory context and evidence limits

antihistamine context

Antihistamine profiles can show a gap between pharmacokinetic persistence and perceived sedation, alertness, or next-day effects.

  • Sedation and anticholinergic effects are not predicted by the curve.
  • Age, co-medications, and formulation can change practical interpretation.
  • Detection, impairment, and safety questions require context beyond half-life.
EvidenceSource trail and model decision

Sources and evidence context

A linked record is not automatically proof of the displayed value. Study, labeling, review, and compound identity sources serve different purposes; notes below identify limitations when they are known.

1 PubMed0 PMC1 DailyMed1 PubChem
  1. Official labeling DailyMed label: HYDROXYZINE PAMOATE CAPSULE [COUPLER LLC].
    Official U.S. product labeling used for formulation and labeled pharmacokinetic context; its statements apply to the described product.
  2. Identity record PubChem Compound Summary: Hydroxyzine.
    Compound identity and naming record. It supplies chemistry context, not independent numerical support for the model.
  3. Research abstract PubMed: Pharmacokinetics of hydroxyzine and cetirizine following oral administration of hydroxyzine to exercised Thoroughbred horses.
    Veterinary pharmacokinetic study; supplemental only and not a direct human half-life estimate.
BoundariesWhat this page cannot answer and where to continue

What this page does not answer

  • It does not estimate impairment, intoxication, or fitness to drive.
  • It does not predict urine, blood, saliva, or hair test results.
  • It does not model repeated exposure, tolerance, withdrawal, or interactions.
  • It does not replace clinician, pharmacist, toxicologist, or emergency guidance.

Continue with context

Read the medical disclaimer, methodology, and research standards before using the model for comparison.