Amobarbital
Aliases: Blues, Amytal, Blue birds, Blue velvet, Blue devils
Summary
Amobarbital (formerly sold as Amytal and as half of Tuinal) is an intermediate-acting barbiturate that potentiates and directly activates GABA-A receptors. The therapeutic index is narrow: doses above approximately 1.5 g have produced fatal respiratory depression. Because its elimination half-life averages 24 hours, next-day cognitive and motor impairment is common.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Oral | 50mg | 50-75mg | 75-150mg | 150mg+ |
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Oral | 15-30 min | 30-60 min | 1-4 hrs | 3-5 hrs | 4.8-10.5 hrs |
| Intravenous | 1-2 min | 5-10 min | 1-4 hrs | 3-5 hrs | 4.1-9.2 hrs |
| Intramuscular | 5-15 min | 15-30 min | 1-4 hrs | 3-5 hrs | 4.3-9.8 hrs |
Tolerance
Build-up
varies by mechanism; therapeutic tolerance may develop over weeks of regular use
Reset
typically days to weeks after discontinuation
Tolerance Decay
Full tolerance
7d
Half tolerance
14d
Baseline
~28d
Tolerance to sedative/hypnotic effects rises quickly with continuous daily use and decays slowly; risk of dose escalation is high because lethal dose does not increase proportionally. Cross‑tolerance with benzodiazepines/Z‑drugs is partial and unreliable for withdrawal management without medical oversight.
Cross-Tolerances
Effects
Positive
- Anxiolysis
- Muscle relaxation
- Anxiolytic
- Muscle Relaxant
Negative
- Ataxia
- Nystagmus
- Respiratory depression
- Sedation
- Slurred speech
- Sedative
- Dystaxia
- Hypnotic
Positive
- Euphoria
- Reduced anxiety
- Cognitive Euphoria
Negative
- Dizziness
- Cognitive suppression
- Anterograde amnesia
- Dream suppression
- Delusions of sobriety
- Amnesia
- Emotional dampening
Positive
- Tactile Enhancement
- Increased Music Appreciation
- Color enhancement
Negative
- Disinhibition
- Decreased Libido
- Acuity Suppression
- Dehydration
- Light sensitivity
- Acuity suppression
- Dulled perception
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