In urine, O-dealkyl and N-deethyl-O-dealkyl metabolites and glucuronides were predominant. Isotonitazene and metonitazene O-dealkyl metabolites have been exactly the same molecules and are also most likely made from the metabolization of structural analogues like etonitazene, protonitazene, or butonitazene, whose only variation from isotonitazene a