N-Desethyl Protonitazene

The following information was compiled in June 2025 and is subject to change as new research is conducted and as new information becomes available:

Description: N-Desethyl protonitazene is a novel synthetic opioid bearing structural similarity to other N-dealkylated nitazene analogues (e.g., N-desethyl isotonitazene, N-desethyl etonitazene). N-Desethyl protonitazene is a primary metabolite of protonitazene; however, it has been discovered as a drug in its own right similarly to the emergence of N-desethyl isotonitazene. N-Desethyl protonitazene was first identified and confirmed in November 2024 by our laboratory.

Sample Source: Chicago Recovery Alliance (Chicago, IL)

Sample Appearance: Yellow powder

Pharmacology: N-Desethyl protonitazene is a mu-opioid receptor agonist and demonstrated in vitro potency greater than fentanyl but less than that of protonitazene and N-desethyl isotonitazene with an EC₅₀ of 10.1 nM (fentanyl: 25.7 nM, protonitazene: 1.57 nM, N-desethyl isotonitazene: 0.317 nM).¹

Toxicology: N-Desethyl protonitazene has not been detected in the absence of protonitazene in toxicology cases to date at the CFSRE.

Drug Materials: N-Desethyl protonitazene has been detected in one drug material to date at the CFSRE.

Demographics / Geographics: The drug material originated from Chicago, IL, and N-desethyl protonitazene was found alongside fentanyl and adulterants (e.g., diphenhydramine, quinine).

Legal Status: N-Desethyl protonitazene is not currently scheduled in the United States.

Class:

Opioid

Appearance:

Yellow powder

Formula:

C21H26N4O3

MW:

382.5

[M+]:

382

[M+H]+:

383.2078

IUPAC:

N-ethyl-2-[5-nitro-2-[(4-propoxyphenyl)methyl]benzimidazol-1-yl]ethanamine

Report Date:

June 16, 2025