4-MeO-Butyrfentanyl is a rare synthetic opioid and analogue of fentanyl, distinct from the related compound butyrfentanyl. It is classified as a research chemical with habit-forming properties. Extremely limited information exists regarding its pharmacology, safety profile, and appropriate dosing parameters. As with other fentanyl analogues, overdose carries a significant risk of respiratory depression. Extreme caution is strongly advised, and it should not be combined with other stimulants or depressants.
Also known as: 4-meo-bf, Para-Methoxybutyrylfentanyl, P-MeO-butyrylfentanyl, 4-Methoxy-butyrylfentanyl, 4-Methoxybutyrfentanyl
Classification
Chemical: Anilidopiperidine
Chemical: Opioid
Psychoactive: Depressant
Tag: Habit-Forming
Tag: Research-Chemical
Tag: Sedative
Tag: Synthetic opioid
Tag: Tentative
Effects
Pain Relief
Sedation
Itching
Miosis
Nausea
Vomiting
Euphoria
Anxiety Suppression
Dissociation
Sadness
Reduced Anxiety
Mood Lift
Dulled Perception
Double Vision
Dehydration
Appetite Suppression
Decreased Libido
Routes of Administration
Oral
Dosage
Heavy: >600 µg
Light: 50–100 µg
Common: 100–300 µg
Strong: 300–600 µg
Threshold: <50 µg (unverified)
Duration
After Effects: 1-2 h
Onset: 5-15 h
Peak: 15-45 h
Offset: 45-90 h
Total Duration: 0.5-2 h
Insufflated
Dosage
Heavy: >400 µg
Light: 25–75 µg
Common: 75–200 µg
Strong: 200–400 µg
Threshold: <25 µg (unverified)
Duration
Onset: 1-2 h
Peak: 10-30 h
Offset: 30-60 h
After Effects: 0.5-2 h
Total Duration: 0.5-1.5 h
Intravenous
Dosage
Heavy: >150 µg
Light: 10–25 µg
Common: 25–75 µg
Strong: 75–150 µg
Threshold: <10 µg (allergy test)
Duration
Onset: 0.5-1 h
Peak: 5-20 h
Offset: 20-40 h
After Effects: 0.5-2 h
Total Duration: 0.33-1 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.
This static page is intended as a readable non-JS and prerender-friendly library export.
Get the full DrugsPRO experience
Open the interactive DrugsPRO app for search, saved items, interactions, and deeper harm reduction tools.
Get the PRO test kit. The simple, quick and reliable drug checking test kit. Visit https://protestkit.eu
4-MeO-Butyrfentanyl - DrugsPRO gwida tal-sustanza
4-MeO-Butyrfentanyl: 4-MeO-Butyrfentanyl is a rare synthetic opioid and analogue of fentanyl, distinct from the related compound butyrfentanyl. It is classified as a research chemical with habit-forming properties. Extremely limited information exists regarding its pharmacology, safety profile, and
