Metonitazene Explained

Metonitazene is an analgesic compound related to etonitazene,^{[1] [2]} which was first reported in 1957,^[3] and has been shown to have approximately 1000 times the potency of morphine by central routes of administration,^[4] but if used orally it has been shown to have approximately 10 times the potency of morphine.^[5]

Its effects are similar to other opioids such as fentanyl and heroin, including analgesia, euphoria, and sleepiness.^[6] Adverse effects include vomiting, and respiratory depression that can potentially be fatal.^[7] Because of high dependency potential and dangerous adverse effects it has never been introduced into pharmacotherapy. It is instead commonly used in the illicit manufacture of counterfeit oxycodone opioid pills.^[8]

Legal status

In the United States, metonitazene is a Schedule I controlled substance under the Controlled Substances Act.

Metonitazene is not controlled under the 1971 Convention on Psychotropic Substances; however, in many countries possession or intent to sell for human consumption might be prosecuted under several analog acts.

Metonitazene became a Class A drug in the UK on 20th March 2024.

See also

• AH-7921
• Etonitazepyne
• Isotonitazene
• MT-45
• Piperidylthiambutene
• U-47700

Notes and References

1. Vandeputte MM, Van Uytfanghe K, Layle NK, St Germaine DM, Iula DM, Stove CP . Synthesis, Chemical Characterization, and μ-Opioid Receptor Activity Assessment of the Emerging Group of "Nitazene" 2-Benzylbenzimidazole Synthetic Opioids . ACS Chemical Neuroscience . 12 . 7 . 1241–1251 . April 2021 . 33759494 . 10.1021/acschemneuro.1c00064 . free . 232337929 . 1854/LU-8714061 .
2. Ujváry I, Christie R, Evans-Brown M, Gallegos A, Jorge R, de Morais J, Sedefov R . DARK Classics in Chemical Neuroscience: Etonitazene and Related Benzimidazoles . ACS Chemical Neuroscience . 12 . 7 . 1072–1092 . April 2021 . 33760580 . 10.1021/acschemneuro.1c00037 . 232356192 .
3. Hunger A, Kebrle J, Rossi A, Hoffmann K . [Synthesis of analgesically active benzimidazole derivatives with basic substitutions] . Experientia . 13 . 10 . 400–401 . October 1957 . 13473817 . 10.1007/bf02161116 . 32179439 .
4. Hunger VA, Kebrle J, Rossi A, Hoffmann K . 1960. Benzimidazol-Derivate und verwandte Heterocyclen III. Synthese von 1-Aminoalkyl-2-nenzyl-nitro-benzimidazolen. Helvetica Chimica Acta. en. 43. 4. 1032–1046. 10.1002/hlca.19600430412 .
5. Bromig G . [New powerful analgetics and their clinical testing] . Klinische Wochenschrift . 36 . 20 . 960–963 . October 1958 . 13612082 . 10.1007/bf01486702 . 1023209 .
6. Krotulski AJ, Papsun DM, Walton SE, Logan BK . Metonitazene in the United States-Forensic toxicology assessment of a potent new synthetic opioid using liquid chromatography mass spectrometry . Drug Testing and Analysis . 13 . 10 . 1697–1711 . October 2021 . 34137194 . 10.1002/dta.3115 . 235460764 .
7. Montanari E, Madeo G, Pichini S, Busardò FP, Carlier J . Acute Intoxications and Fatalities Associated With Benzimidazole Opioid (Nitazene Analog) Use: A Systematic Review . Therapeutic Drug Monitoring . 44 . 4 . 494–510 . August 2022 . 35149665 . 10.1097/FTD.0000000000000970 . 246776288 .
8. Web site: A synthetic opioid stronger than fentanyl and hundreds of times more potent than heroin is emerging in Australia . ABC News . 25 June 2024 . en-AU . 24 June 2024.