TABLE 1.

Current list of specifically scheduled fentanyl‐related substances (DEA “Orange Book” https://www.deadiversion.usdoj.gov/schedules/orangebook/orangebook.pdf (accessed February 2, 2021)

Listed as schedule I	Listed as schedule I	Listed as schedule II
acetyl fentanyl	β‐hydroxyfentanyl	alfentanyl
acetyl‐α‐methylfentanyl	β‐hydroxy−3‐methylfentanyl	carfentanil
acryl fentanyl	β‐hydroxythiofentanyl	fentanyl
butyryl fentanyl	isobutyryl fentanyl	norfentanyl
ρ‐chlororisobutyryl fentanyl	methoxyacetyl fentanyl	remifentanil
crotonyl fentanyl	ρ‐methoxybutyryl fentanyl	sufentanil
cyclopentyl fentanyl	α‐methylfentanyl	thiafentanil
cyclopropyl fentanyl	3‐methylfentanyl
ρ‐fluorobutyryl fentanyl	α‐methylthiofentanyl
2‐fluorofentanyl	3‐methylthiofentanyl
ρ‐fluorofentanyl	ocfentanil
4‐fluoroisobutyryl fentanyl	tetrahydrofuranyl fentanyl
furanyl fentanyl	thiofentanyl
	valeryl fentanyl