Hydroxyzine
Aliases: Atarax, Hyzine, Rezine, Vistaril, Vistaject
Categories
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. QT prolongation is a rare but serious concern—avoid in patients with baseline QT risk or family history. Alcohol should be strictly avoided, especially in significant amounts.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral | - | 25-100mg | - | - |
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | After Effects | Total |
|---|---|---|---|---|---|---|
| Oral | 15-30 min | 30-45 min | 2 hrs | 2-3 hrs | 60-0 min | 180-0 min |
| Intramuscular | 15-30 min | 15-30 min | 1-2 hrs | 2-3 hrs | 60-0 min | 180-0 min |
Tolerance
Build-up
sedative effects diminish within 1–2 weeks of daily use
Reset
a few days of abstinence
Cross-tolerance
Effects
Positive
- Muscle relaxation
Negative
- Dry mouth
- Motor impairment
- Increased heart rate
- Muscle cramps
- Nausea
- Tremors
- Sedation
- Antipruritic effect
- Difficulty urinating
Positive
- Anxiety reduction
- Relaxation
Negative
- Drowsiness
- Dizziness
- Delirium
- Confusion
- Dysphoria
- Anxiety
- Mental cloudiness
- Time distortion
Positive
Negative
- Blurred vision
- Blurred Vision
- Dulled perception
- External hallucinations
- Internal hallucinations
- Visual and audio distortions
- Perception of Bodily Heaviness
- External Hallucination
- Auditory Hallucination
- External hallucination