What is Carfentanil? Carfentanil (or carfentanyl) is an analogue of the synthetic opioid analgesic fentanyl. It is one of the most potent opioids known. Its potency is approximately 10,000 times stronger than morphine and 100 times stronger than fentanyl. It is a general anesthetic designed for large animals.
Carfentanil was sold starting in 1986 under the brand name “Wildnil” for use in tranquilizer darts in combination with an α2-adrenoreceptor agonist for large mammals including elk and elephants. It was chosen for its high therapeutic index. Commercial production of Wildnil ceased in 2003, and the drug is available only as a compounded dosage form.
What does carfentanil look like?
Carfentanil is a white powdery substance resembling heroin.
How is carfentanil abused?
Carfentanil is added to street heroin or is sold as heroin without the user’s knowledge. It can be snorted, smoked or injected. It can also be absorbed through the skin.
Carfentanil is a lipophilic chemical, and can easily cross the blood-brain barrier. It has very rapid onset of effects, but is also shorter acting than fentanyl. For pain relief, a unit of carfentanil is 100 times as potent as the same amount of fentanyl, 5,000 times as potent as a unit of heroin and 10,000 times as potent as a unit of morphine. This is despite only having 14-135 times higher affinity for the μ receptor.