Index > Factsheets > Fentanyl


SummaryFentanyl is a synthetic opiate analgesic with a rapid onset and short duration of action. It is a strong agonist at the μ-opioid receptors and is historically used to treat breakthrough pain. Fentanyl is approximately 100 times more potent than Morphine, and is commonly used as a patch. Sometimes used as an adulterant for heroin, which has led to many overdose deaths.
DoseIntranasal Light: 10-25ug Common: 25-50ug Strong: 50-75ug+
Transdermal Light: 12.5ug/hr Common: 25-50ug/hr Strong: 50-100ug/hr
NOTE: Due to Fentanyl's high potency, it is incredibly difficult to measure safely, and so can easily lead to overdose.
OnsetTransdermal: 90-180 minutes.
Buccal: 15-30 ninutes
Insufflated: 5-15 minutes.
DurationTransdermal: 48-72 hours. | Buccal: 1-4 hours. | Insufflated: 1-4 hours.
EffectsAnalgesia, euphoria, feelings of relaxation, sedative effects, changes in focus, attention, respiratory depression, nausea, constipation, dry mouth, somnolence, confusion, weakness, sweating, fatigue, dizziness, anxiety
BioavailabilitySublingual/Buccal 50% | Insufflated 70% | Transdermal 92%
WarningRisk of post-acute withdrawal effects, including depression, anxiety disorder, psychosis, suicidal ideation in extreme cases.