Summary
Etonitazene is an extremely potent synthetic opioid discovered in 1957, approximately 1,000-1,500 times stronger than morphine in animal studies but likely 60 times stronger in humans. It was never approved for medical use due to severe dependency potential and respiratory depression. Etonitazene has an unpredictably steep dose-response curve and erratic pharmacokinetics, especially when injected, making it more hazardous than fentanyl. It has sporadically appeared in illicit drug supplies since the 1960s. Multiple doses of naloxone may be required to reverse an overdose, and renarcotization can occur as naloxone wears off.
Dose Information
Light
Common
Strong
Heavy
Onset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | After Effects |
|---|---|---|---|---|---|
| Oral | 5-15 min | 15-30 min | 1-3 hrs | 2-4 hrs | 2-6 hrs |
| Insufflated | 2-10 min | 10-20 min | 1-2 hrs | 1-3 hrs | 2-4 hrs |
| Intravenous | 1 min | 2-5 min | 30 min | 1-2 hrs | 1-4 hrs |
| Smoked | 1-3 min | 5-15 min | 30 min | 1-2 hrs | 1-4 hrs |
Tolerance
Build-up
develops within days of regular use; analgesic tolerance faster than respiratory depression tolerance
Reset
7–14 days for partial reset; full reset may take weeks — tolerance loss greatly increases overdose risk
Effects
Positive
- Physical euphoria
- Pain relief
- Muscle relaxation
- Analgesia
Negative
- Respiratory depression
- Nausea
- Sedation
- Difficulty urinating
- Itchiness
- Pupil constriction
Positive
- Cognitive euphoria
- Anxiety suppression
- Reduced anxiety
- Wakefulness
- Motivation enhancement
- Euphoria
Negative
- Compulsive redosing
- Constipation
- Motivation suppression
- Anxiety
Positive
- Warmth
- Increased music appreciation
- Increased libido
Negative
- Appetite suppression
- Light sensitivity
- Disinhibition
- Dehydration
- Dulled perception
- Internal hallucination
- Warm flush