What are the difference in potency between Protonitazene and isotonitazene, etonitazene and metonitazene?. To order nitazenes. Contact: (Tellychemicals@protonmail.com) The potency of certain nitazene analogs (e.g., isotonitazene, protonitazene, and etonitazene) greatly exceeds that of fentany but butonitazene and flunitazene potency below fentanyl.