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Research and analysis

ACMD advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids

A review of the evidence on the use and harms of 2-benzyl benzimidazole (nitazene) and piperidine benzimidazolone (brorphine-like) opioids.

Updates to this page

From:
Advisory Council on the Misuse of Drugs
Published:
18 July 2022
Last updated:
10 June 2026
Show all updates

  1. Added government response to seventh addendum.

  2. Document added: Seventh addendum to the ACMD report on the use and harms of 2-benzyl-benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids.

  3. Added government response to the ACMD's sixth addendum advice on nitazenes.

  4. Published the sixth addendum to the ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids.

  5. Added the government response to the ACMD's fifth addendum on nitazenes and related opioids.

  6. A fifth addendum has been added, recommending the proposed generic definition be further updated to capture the newly identified compound aminoisotonitazene and any structurally related compounds to it that may appear in future. This generic definition has also been expanded to capture carbamoyl derivatives of 2-benzyl benzimidazole (nitazene) opioids.

  7. Added the government response to the ACMD's fourth addendum on nitazenes.

  8. A fourth addendum has been added, recommending the proposed generic definition be further updated to capture the suspected newly identified compound methylenedioxynitazene and any structurally related compounds to it that may appear in future. The response to the third addendum (originally published on 21 March 2024) has also been moved to this page.

  9. Updated to include recommendation that the proposed generic definition be updated to address other structurally related compounds similar to ethyleneoxynitazene that might appear in the future.

  10. Government response to the addendum advice of 6 October published.

  11. Updated to include consideration of a further 4 newly detected 2-benzyl benzimidazole (nitazene) opioids.

  12. Added government response to the ACMD’s advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids.

  13. Updated to include consideration of a new synthetic opioid.

  14. First published.

Documents

ACMD advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids (accessible version)

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ACMD advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids

PDF, 385 KB, 48 pages

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Cover letter from ACMD with advice on benzyl benzimidazole and piperidine benzimidazolone opioids (accessible version)

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Cover letter from ACMD with advice on benzyl benzimidazole and piperidine benzimidazolone opioids

PDF, 148 KB, 9 pages

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First addendum to ACMD’s report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids (accessible version), 19 December 2022

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First addendum to ACMD’s report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 19 December 2022

PDF, 136 KB, 2 pages

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Government response to the ACMD’s advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids (accessible version)

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Government response to the ACMD’s advice on 2-benzyl benzimidazole and piperidine benzimidazolone opioids

PDF, 351 KB, 4 pages

Second addendum to ACMD’s report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 6 October 2023 (accessible version)

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Second addendum to ACMD’s report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 6 October 2023

PDF, 133 KB, 3 pages

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Government response to the second ACMD addendum advice on nitazenes (accessible), 18 October 2023

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Government response to the second ACMD addendum advice on nitazenes, 18 October 2023

PDF, 104 KB, 2 pages

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Third addendum to ACMD's report on the use and harms of 2-benzyl benzimidazole ('nitazenes') and piperidine benzimidazolone ('brorphine-like') opioids, 15 December 2023 (accessible)

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Third addendum to ACMD's report on the use and harms of 2-benzyl benzimidazole ('nitazenes') and piperidine benzimidazolone ('brorphine-like') opioids, 15 December 2023

PDF, 221 KB, 2 pages

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Government response to the third addendum to the ACMD's report on 2-benzyl benzimidazole and piperidine benzimidazolone opioids, 21 March 2024

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Fourth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine- like’) opioids, 5 April 2024 (accessible version)

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Fourth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine- like’) opioids, 5 April 2024

PDF, 114 KB, 2 pages

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Government response to the ACMD's fourth addendum on nitazenes (accessible)

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Government response to the ACMD's fourth addendum on nitazenes

PDF, 138 KB, 2 pages

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Fifth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 8 November 2024 (accessible version)

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Fifth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 8 November 2024

PDF, 127 KB, 2 pages

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Government response to the ACMD on fifth addendum on nitazenes and related opioids (accessible version)

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Government response to the ACMD on fifth addendum on nitazenes and related opioids

PDF, 284 KB, 2 pages

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Sixth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 21 October 2025 (accessible)

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Sixth addendum to ACMD report on the use and harms of 2-benzyl benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 21 October 2025

PDF, 95.2 KB, 2 pages

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Government response to the ACMD's sixth addendum advice on nitazenes (accessible)

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Government response to the ACMD's sixth addendum advice on nitazenes

PDF, 185 KB, 3 pages

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Seventh addendum to the ACMD report on the use and harms of 2-benzyl-benzimidazole (‘nitazene’) and piperidine benzimidazolone (‘brorphine-like’) opioids, 30 April 2026

PDF, 335 KB, 10 pages

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Government response to the ACMD's seventh addendum on orphines (accessible)

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Government response to the ACMD's seventh addendum on orphines

PDF, 320 KB, 4 pages

Details

This report from the Advisory Council on the Misuse of Drugs (ACMD) describes the use and harms of 2-benzyl benzimidazole (nitazene) opioids (including isotonitazene) and piperidine benzimidazolone opioids (including brorphine).

The report contains recommendations on the classification and scheduling of isotonitazene, brorphine and related substances, following a thorough review of the evidence available and consideration by the ACMD’s Novel Psychoactive Substances Committee.

Since its publication in July 2022, the ACMD has published addenda recommending control of newly identified 2-benzyl benzimidazole compounds by name, following detections in drug seizures and a review of their potential harms.

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