Alfentanil is a short-acting synthetic opioid analgesic approximately one-quarter to one-tenth the potency of fentanyl, with a rapid onset (1-2 minutes) and brief duration (30-60 minutes). Almost exclusively used in controlled medical anesthesia settings for surgical procedures requiring precise, short-term analgesia. Carries extreme risk of life-threatening respiratory depression, particularly when combined with other CNS depressants. Classified as Schedule II in the United States due to high abuse potential and risk of fatal overdose.
Alfentaniili molecular structure diagram from the DrugsPRO substance library.
Also known as: Alfenta, Rapifen, R-39209, Alfentanyl, Fanaxal
Classification
Chemical: Anilidopiperidine
Chemical: Opioid
Psychoactive: Depressant
Tag: Anilinopiperidine
Tag: Habit-Forming
Effects
Pain Relief
Sedation
Respiratory Depression
Nausea
Itching
Physical Euphoria
Euphoria
Cognitive Euphoria
Anxiety Suppression
Sadness
Compulsive Redosing
Dissociation
Dulled Perception
Open Eye Visuals
Sound Dampening
Routes of Administration
Intravenous
Dosage
Threshold: 2-4 ug/kg
Light: 4-8 ug/kg
Common: 8-20 ug/kg
Strong: 20-40 ug/kg
Heavy: 40+ µg/kg
Duration
Onset: 0.02-0.03 h
Comeup: 0.03-0.08 h
Peak: 0.08-0.25 h
Offset: 0.25-0.5 h
After Effects: 0-30 h
Total Duration: 30-60 h
Harm Reduction
Check interactions before mixing substances, pay attention to dose spacing and hydration, and treat all dosage guidance as approximate rather than guaranteed safe.
Sources
Substance data is aggregated from the following public harm-reduction and reference sources.
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Alfentanil - DrugsPRO aineopas
Alfentanil: Alfentanil is a short-acting synthetic opioid analgesic approximately one-quarter to one-tenth the potency of fentanyl, with a rapid onset (1-2 minutes) and brief duration (30-60 minutes). Almost exclusively used in controlled medical anesthesia settings for surgical procedures requiring