Hydroxyzine
Aliases: Atarax, Hyzine, Rezine, Vistaril, Vistaject
Summary
Hydroxyzine is an FDA-approved first-generation antihistamine commonly used short-term for anxiety, pruritus, and premedication. At normal therapeutic oral doses (25-50 mg), hydroxyzine has no significant respiratory depressant effects on its own. Tolerance to CNS effects develops rapidly (3-7 days), limiting long-term anxiolytic efficacy; maximum recommended duration is 4 months for anxiety.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral | - | 25-100mg | - | - |
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 15-30 min | 30-45 min | 2-2 hrs | 2-3 hrs | 4.8-6.2 hrs |
| Intramuscular | 15-30 min | 15-30 min | 1-2 hrs | 2-3 hrs | 3.5-6 hrs |
Tolerance
Build-up
sedative effects diminish within 1–2 weeks of daily use
Reset
a few days of abstinence
Tolerance Decay
Full tolerance
3d
Half tolerance
4d
Baseline
~5d
Cross-Tolerances
Diphenhydramine
30%
Doxylamine
30%
Effects
Aggregated from 15 Erowid experience reports
Positive Effects 5
Anxiety Suppression
73.3%
70%
Sedation
60.0%
70%
Euphoria
33.3%
70%
Focus Enhancement
20.0%
70%
Stimulation
20.0%
70%
Adverse Effects 0
Combinations
Pill Identifiers
41
known pill identifiers on record — view imprints, colors, shapes, and images
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Hydroxyzine's nerd page
Pharmacology, chemical data, effect profiles, and more
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