Remifentanil
Aliases: Ultiva
Summary
Standard anesthetic practice uses continuous infusions of 0.05-0.25 ug/kg/min; analgesia ceases within approximately 5 minutes of pump stoppage due to ester hydrolysis. Context-sensitive half-life is 2-4 minutes regardless of infusion length. Bolus dosing outside monitored settings is strongly discouraged because apnea can occur before the syringe is empty.
Dose Information
| ROA | Light | Common | Strong | Heavy |
|---|---|---|---|---|
| Intravenous | 10-20ug | - | - | 100+ug(dangerous)+ |
Onset, Duration & After-effects
| ROA | Onset | Peak | Offset |
|---|---|---|---|
| Intravenous | 1-1 min | 1-2 min | 3-5 min |
Effect Profile
Scores (1–10) curated from multiple sources:
- Effect keyword matching from PsychonautWiki catalog
- Weighted by importance: core (×3), major (×2), minor (×1)
Strong euphoria and pain relief with moderate itching/nausea, low sedation
Tolerance
Tolerance Decay
Clinically, meaningful tolerance to remifentanil’s analgesia can develop within hours of infusion; tolerance decays over days to weeks after cessation. Values are approximate and based on clinical observations of acute tolerance rather than long-term dependence.
Cross-Tolerances
Effects
- Physical euphoria
- Pain relief
- Analgesia
- Respiratory depression
- Bodily control impairment
- Nausea
- Sedation
- Itchiness
- Pupil constriction
- Muscle rigidity
- Cognitive euphoria
- Reduced anxiety
- Euphoria
- Anxiety suppression
- Mood lift
- Constipation
- Compulsive redosing
- Dizziness
- Motor control loss
- Physical autonomy
- Warmth
- Color enhancement
- Increased music appreciation
- Brightened colour
- Light sensitivity
- Appetite suppression
- Disinhibition
- Dehydration
- Dulled perception
- Drifting