2018 WHO Executive Summary:
Receptor binding data show that orthofluorofentanyl binds selectively to the u subtype of opioid receptors with subnanomolar affinity relative to 8 and k opioid receptors (DEA-VA, 2017). No pharmacokinetic or pharmacodynamic studies of orthofluorofentanyl are reportedin the preclinical or clinical scientific literature. It first appeared in toxicological assaysin the U.S. in 2016. Based primarily on reports of overdoses attributed to orthofluorofentanyl describing naloxone-reversible loss of consciousness, depressed respiration, and miosis, it appears to be a potent mu opioid receptor agonist. As such, its pharmacology and toxic effects are likely to be similar to fentanyl. It currently has no legitimate medical or veterinary uses. Orthofluorofentanyl is being sold as heroin or an adulterant in heroin. Starting in 2016,a number of fatalities have been associated with this substance (1 in Europe and 16 in the U.S.) and it was placed in Schedule 1 by the U.S. on a temporary basis. Because orthofluorofentanyl cross-reacts with standard fentanyl immunoassays, it is possible that the number of deaths associated with it are underreported. The totality of data currently available on orthofluorofentanyl suggests that it has high abuse potential and poses a serious public health threat.

Critical Review Report: ORTHOFLUOROFENTANYL (PDF 12 pages):
https://www.who.int/medicines/access/controlled-substances/Orthofluorofentanyl.pdf?ua=1

Ortho-Fluorofentanyl Monograph (PDF 5 pages):
https://www.swgdrug.org/Monographs/ortho-Fluorofentanyl.pdf

Ortho-Fluorofentanyl (Hydrochloride) Safety Data Sheet (PDF 5 pages):
https://www.caymanchem.com/msdss/19425m.pdf

An opioid analgesic that is an analog of fentanyl and has been sold online as a designer drug. While the structural isomer p-fluorofentanyl was one of the first illicit fentanyl analogues identified in 1981, Orthofluorofentanyl did not appear on the illicit market until August 2016. Orthofluorofentanyl was placed into Schedule I in the US in October 2017.