Independent report

Cover letter: ACMD review of the evidence on the use and harms of etomidate

Published 21 October 2025

ACMD Chair: Prof Owen Bowden-Jones NPS Committee Secretary: Yetunde Animashawun

1 st Floor (NE)
Peel Building
2 Marsham Street
London
SW1P 4DF

ACMD@homeoffice.gov.uk

Rt Hon Sarah Jones MP Minister of State (Minister for Crime and Policing)

2 Marsham Street
London
SW1P 4DF

22 October 2025

Dear Minister,

1. Re: ACMD report – A review of the evidence on the use and harms of etomidate and related compounds

In recent years, there has been a growing number of reports highlighting the non-medical use of etomidate internationally, particularly in the Far East.

Etomidate is a centrally acting drug known for its sedative properties and is primarily used as an intravenous anaesthetic in clinical settings.

The Advisory Council on the Misuse of Drugs (ACMD) is pleased to enclose the attached report describing the use and harms of etomidate and other structurally related compounds.

In Asia and New Zealand, etomidate has been identified in e-cigarettes and vaping devices with smoking products colloquially referred to as ‘space oil’ or ‘kpods’. Whilst prevalence data in the UK is currently limited, this emerging trend of use elsewhere presents the potential for a significant future public health issue for the UK.

Following a comprehensive review of the available evidence, the report presents recommendations regarding the classification and scheduling of etomidate and structurally related compounds. The ACMD is grateful to both national and international experts who contributed their insights to this review.

Based on the evidence obtained and reviewed on the uses and harms of etomidate, the ACMD has recommended that it should be controlled under the Misuse of Drugs Act 1971 (MDA) under Class C and placed in Schedule 4 (Part 1) of the Misuse of Drugs Regulations 2001 (MDR). Additionally, the

ACMD recommends that due to the absence of any legitimate uses for compounds structurally related to etomidate, a UK generic definition be drafted and consulted on prior to its inclusion in the MDA. The ACMD also recommends that those compounds covered by the generic control should be listed under Schedule 1 of the Misuse of Drugs Regulations.

The ACMD have drawn the following conclusions, options for control and recommendations from the evidence presented in this report:

1.1. Etomidate is a modulator of the GABA-A receptor that is licensed for use in humans as an ultra-short-acting (rapid onset and rapid offset) intravenous drug for the induction of anaesthesia, although its use in clinical practice is limited by its dose-dependent inhibition of adrenal steroid synthesis. Currently, it is usually only used in patients with unstable or high-risk aortic stenosis or mitral stenosis surgery.

1.2. There are a number of related compounds that have structural similarities to etomidate and also have similar clinical effects, but some potentially do now have the unwanted effects reported with etomidate on adrenal steroid synthesis.

1.3. Since 2011 there have been reports of non-medical (recreational) use of etomidate, particularly from countries in Asia such as China, Hong Kong, Taiwan and the Republic of Korea, and New Zealand. This use is largely due to the “rapid onset/offset” of desired effects with no ongoing hangover effects after use, and because of this it is often known as “Space Oil”. These reports have increased significantly over the last 2 to 3 years.

1.4. Information on the acute toxicity of these compounds from case reports and series of non-medical use from Asia demonstrates that etomidate is associated with sedation, which can be clinically significant. In addition, both short and long-term non-medical use has been reported to be associated with clinical and biochemical features consistent with inhibition of adrenal steroid synthesis.

1.5. There have been only two published reports to date of dependency and associated withdrawal related to the long-term use of etomidate; both required hospital admission to manage the clinical effects of the withdrawal.

1.6. Due to their sedative effects individuals who themselves use etomidate or related compounds or are exposed intentionally to these compounds by other individuals with the intent of causing sedation to facilitate crimes, may be the victim of crimes such as robbery, assault and sexual assault. There is the potential that etomidate and related compounds may increase the risk to the individual and the public when an individual is driving under the influence of these compounds.

1.7. Where countries have tried to implement mechanisms to control etomidate due to its increased availability and use, there has subsequently been an increase in the detection of related, but uncontrolled, compounds such as metomidate, propoxate and isopropoxate.

1.8. Currently there is limited evidence of detection and/or use of etomidate and related compounds in the UK; however, this may in part be due to the lack of routine testing of e-liquids and other vaping related products, and so the true availability and use in the UK is likely to be significantly underestimated.

1.9. Given the reported harms of these products in other countries, and the potential risk that the availability and use of these etomidate and related compounds will increase in the UK, the ACMD advises that control of etomidate and related compounds via the Misuse of Drugs Act 1971 is required at this time, rather than waiting until there is an increase in reported harms related their use in the UK.

1.10. The ACMD review shows that the harms could be considered to be broadly equivalent to those of other sedatives such as benzodiazepines, zopiclone or pregabalin, so listing in Class C is recommended.

1.11. Etomidate is licenced for clinical use in areas, although the actual therapeutic use of etomidate for the induction of anaesthesia is relatively low. Therefore, the ACMD would recommend that etomidate is listed in Schedule 4 (Part 1) of the Misuse of Drugs Regulations 2001. As the other related compounds covered by the recommended generic control currently have no legitimate medical or other uses, the ACMD would recommend that these are listed in Schedule 1 of the Misuse of Drugs Regulations 2001.

2. Recommendation 1

Whilst there is currently limited evidence of detection and/or use of etomidate and related compounds in the UK, due to the potential risk that the availability and use of these etomidate and related compounds will increase in the UK, the ACMD advises that control of etomidate and related compounds via the Misuse of Drugs Act 1971 is required. The harms are broadly equivalent to those of other sedatives such as benzodiazepines, zopiclone or pregabalin, so listing in Class C is recommended.

As etomidate is licensed for use in medical practice, it should be listed in Schedule 4 (Part 1) of the Misuse of Drugs Regulations 2001. As there are a range of simple variants of etomidate which could be or have already been encountered, a small generic control, similar to that used in Hong Kong legislation, should be drafted and consulted on to cover these compounds.

Since those compounds, apart from etomidate, have no legitimate medical or other use, those covered by the generic control should be listed in Schedule 1 of the Misuse of Drugs Regulations 2001. They should also be designated as controlled drugs to which section 7(4) of the 1971 Act applies.

Lead: Home Office.

Measure of outcome: The inclusion of the etomidate and related compounds in Class C of the Misuse of Drugs Act 1971, with etomidate in Schedule 4 (Part 1) and the other related compounds in Schedule 1 of the Misuse of Drugs Regulations 2001.

3. Recommendation 2

Due to limited testing of e-liquids seized at the border or by police, the true availability and use of etomidate and related drugs, which are widely reported in Asia and New Zealand to occur through vaping of e-liquids, is likely to be significantly underestimated at this time.

The ACMD would recommend that law enforcement bodies and Trading Standards should be encouraged to submit samples of seized vaping products for analysis in order to allow monitoring of this new route for drug administration. This should be coupled with an increase in the availability and capability of UK-based analytical services to enable wider testing of e-liquids in order to be able to determine the true threat to the UK public from drugs such as etomidate which can be consumed through vaping of e-liquids containing them.

Forensic science providers and others need to ensure that they have the ability and capacity to analyse e-liquids and other products designed for vaping, as well as the ability to detect etomidate and related compounds.

Leads: OHID, Home Office, Forensic Science Providers

Measure of outcome: Increased sampling and availability of testing of e- liquids and reporting of findings; in addition, forensic science providers need to ensure that there is testing of clinical, post-mortem and other samples for etomidate and related compounds that may be used by vaping.

4. Recommendation 3

Emerging evidence from Asia and Oceania indicates increasing use of etomidate and related analogues in vaping products, with limited current visibility in UK data. Given the rapid global spread of NPS, including those delivered via e-liquids, the ACMD recommends strengthening international collaboration and data sharing with key partners.

The ACMD recommends that there should be enhanced engagement with international drug monitoring systems (e.g. UNODC, EUDA), regional early warning networks, and forensic laboratories will support earlier detection and improved risk assessment of substances such as etomidate analogues entering the UK.

There needs to be monitoring of the impact of any national and/or international control of etomidate and related compounds on the emergence of other drugs to replace those that have been controlled.

Leads: OHID, Home Office, and UK Focal Point on Drugs

Measure of outcome: Increased participation in international NPS data exchanges; evidence of timely UK reporting and response to emerging etomidate-related threats identified abroad.

5. Recommendation 4

Currently there is no information for potential users of etomidate and related compounds, as well as healthcare professionals, on the acute health risks associated with the non-medical use of these compounds. In addition, due to the risk of inadvertent overdose this potentially puts individuals at risk of acquisitive crime due to their sedative effects.

The ACMD recommends that information on acute health risks of etomidate and related compounds, and on the risks of exposure to psychoactive materials in vaping products should be made available to the public and healthcare professionals.

Leads: Department for Education, Office for Health Improvement and Disparities, Local Government Association, FRANK, DAN 24/7 (Betsi Cadwaladr University Health Board), Know the Score (Scotland), National Poisons Information Service, Scottish Government Population Health Directorate, Welsh Government – Department for Education and Welsh Language, Department of Education (Northern Ireland).

Measure of outcome: Availability of information to the general public and healthcare professionals on the harms and risks of using etomidate and related compounds.

We welcome the opportunity to discuss this report in due course.

Yours sincerely,

Professor Owen Bowden-Jones Chair of the ACMD

Professor David Wood Chair of the ACMD Etomidate Working Group