“Space Oil” and Etomidate in the Drug Supply: Hidden Sedation and Adrenal Crisis

Summary

“Space oil” is a street term for vape cartridges containing the anaesthetic etomidate or its analogues mixed with fentanyl and other drugs. Since 2023, space‑oil vaping has become a crisis in Hong Kong and is now spreading to North America and Europe. Teenagers think they are just inhaling a harmless oil, but they are actually consuming an intravenous anaesthetic designed to put adults to sleep during surgery. Etomidate’s side effects include profound sedation, respiratory depression when combined with opioids, and adrenal suppression that can lead to hypotension, hyponatraemia, and shock. This blog summarises the latest research, case reports, and public health alerts on the misuse of etomidate via e‑cigarettes. It explains how healthcare providers and the public can recognise and respond to this hidden threat.

What is Space Oil?

Space oil describes e‑liquids (vapes) containing etomidate or similar compounds (isopropoxate, propoxate, metomidate) mixed with fentanyl or other drugs. The term comes from the oil's glassy appearance and the sense of detachment it produces. Etomidate is a short‑acting sedative‑hypnotic used in anaesthesia; it binds to the GABA‑A receptor, induces unconsciousness within one minute, and lasts about 3–5 minutes. Clinically, etomidate has little effect on blood pressure and heart rate, making it a favoured choice for patients with cardiovascular instability. However, even a single dose can suppress the adrenal cortex, reducing cortisol and aldosterone production for 6–8 hours. Combining etomidate with fentanyl or medetomidine increases the risk of profound respiratory depression.

Origins and Spread

• Hong Kong (2023–2024). In late 2023, Hong Kong authorities began detecting etomidate in “space‑oil” vapes sold through social‑media dealers. Adolescents purchased capsules via WhatsApp or other apps and inhaled them through e‑cigarettes. The Hong Kong Poison Control Centre recorded 45 cases of space‑oil misuse between May and December 2024, and public hospitals treated more than 130 suspected users in 2024, with three deaths. About a quarter of the patients were under 18. Etomidate and its analogues were added to the city’s Dangerous Drugs Ordinance in February 2025.

• Spread to the United States and Canada (2024). The UN Office on Drugs and Crime reported in March 2025 that Philadelphia detected etomidate in the illicit drug supply in August 2024, where it was co‑detected with fentanyl and medetomidine. The Philadelphia Department of Public Health’s surveillance program noted that this may have been the first detection of etomidate in U.S. street drugs. The UN ODC also noted detections in Canada and Europe.

• “Space Oil” goes global. Drug‑checking services in the UK found etomidate in at least nine samples, often combined with potent opioids such as protonitazene and diazepam. Singapore, New Zealand, and other regions have also seized vape cartridges containing etomidate. These detections suggest that clandestine networks are marketing etomidate‑laced vapes as exotic highs, especially to teens and young adults, and the phenomenon is no longer confined to Asia.

Etomidate Pharmacology and Adrenal Suppression

Etomidate’s anaesthetic effect comes from enhancing GABA‑A receptor activity. It is metabolised in the liver and excreted via urine. However, etomidate is unique among anaesthetics because it inhibits 11‑β‑hydroxylase, the enzyme required for cortisol and aldosterone synthesis. After even a single bolus, adrenal suppression may last 6–8 hours, and with continuous infusion, it can persist 24–48 hours. Adrenal suppression causes decreased cortisol and aldosterone and accumulation of precursors like 11‑deoxycorticosterone, which may lead to:

• Hypotension and shock (due to decreased vascular tone and volume)

• Hyponatraemia and hyperkalaemia (due to loss of aldosterone)

• Weakness, confusion, and seizures

• In severe cases, adrenal crisis and death.

In anaesthesiology, this risk is mitigated by avoiding repeated doses and by monitoring adrenal function. When etomidate is inhaled via e‑cigarettes, users may take repeated hits over hours or days, leading to chronic suppression with no clinical oversight.

Evidence from Case Reports

Hong Kong case series. A 2024 case series in the Hong Kong Medical Journal described three local teenagers (ages 15–17) who developed adrenal insufficiency after inhaling space‑oil e‑cigarettes. All three presented with weakness, dizziness, and low sodium, and two required hydrocortisone replacement therapy. The study highlighted that these were the first paediatric cases of adrenal insufficiency linked to etomidate misuse and noted an upward trend in teen presentations since 2023. The report emphasised that long‑term inhalation can deliver variable and unknown doses of etomidate

Philadelphia detection. The Philadelphia Department of Public Health issued a health alert in August 2024 after finding etomidate in the drug supply alongside fentanyl and medetomidine. The alert underscored that etomidate produces sedation by binding to GABA receptors, with an onset of 1 minute and a duration of action of 3–5 minutes. Still, its most significant adverse effect is transient adrenal suppression. The alert advised clinicians and first responders to be aware that naloxone may reverse the opioid component of an overdose, but sedation may persist due to etomidate or other sedatives.

South China Morning Post report. A news article summarising a case report noted that three boys aged 15–17 suffered adrenal insufficiency after using space oils. The article highlighted that etomidate is the main ingredient and has become popular among youth since 2023. Lawmakers sought to rename the drug to avoid glamorising it.

Health Effects and Clinical Presentation

People who inhale space‑oil vapes may experience:

Public health and harm-reduction implications

People underestimate the risk

Many users do not think space oil is dangerous. Also, Many teenagers buy space oil capsules through messaging apps. They think they are just vaping. The Straits Times reported that, in Hong Kong in 2024, space oil was the third most abused drug among youth. It came after cannabis and cocaine. The same report listed possible harms. These include addiction, tremors, dizziness, memory loss, seizures, blackouts, and death.

Space oil is sold like a normal vape product. So parents and teens may not realize what it is. They may not know they are inhaling an anesthetic.

Law enforcement responses

Hong Kong outlawed the use of etomidate and related substances in February 2025. Dealers who were found selling space oil online were arrested. Police have confiscated many cartridges. The police also report that the majority of users are juveniles. There are fears this could spread to other countries via social media. When assessing a patient for unexplained sedation or unknown low blood pressure, clinicians should inquire if the patient is using e-cigarettes and/or "space oil". In cases of suspected adrenal insufficiency, this will also be important.

Naloxone is not enough

In most instances of overdosing on "space oil", naloxone treats only the opioid aspect of the overdose. Naloxone does not reverse the effects of etomidate sedation on a patient who has overdosed on space oil. As a result, after treatment with naloxone, a patient may still be in a state of sedation and, therefore, will require additional support to assist with their breathing. In addition to naloxone, responders should also consider administering additional sedative medications such as etomidate, xylazine, or benzodiazepines. Etomidate, especially, has been known to impact the adrenal glands of an overdose victim for several hours, and therefore, even if a patient appears to have recovered somewhat from an overdose, they may still be at risk for developing hypotension (low blood pressure) and electrolyte abnormalities within a few hours post-overdose. Patients who have taken etomidate require close observation following an overdose, regardless of how well they appear to have recovered from the initial effects of the overdose.

Clinical Recommendations

• If an individual becomes lethargic and depressed on the respiratory system after using an unknown drug or electronic cigarette, particularly if they remain unresponsive after receiving naloxone, they should be suspected of having suffered from a space oil exposure.

• For those individuals who demonstrate symptoms of continued hypotension, continued hyponatremia, or an unexplained shock, if cortisol and ACTH levels remain high, hydrocortisone may be of benefit in the management of this syndrome.

• Following suspected etomidate exposure, keep a close watch on these patients for at least 6-8 hours after their suspected overdose, as not only sedation but also endocrine symptoms may continue for an extended period after overdose.

• Patients should be educated about the risks associated with vapour products, as not all are safe. Some may contain very strong sedatives and/or opioids.

• Contact your local Poison Control Centre and/or state Public Health Agency to report any suspected cases of exposure to space oil so these agencies can help track emerging trends in sedative use.

Conclusion

The evolution of illegal drug markets is evident in the emergence of space oil and how quickly dealers are converting how and what they sell from prescription medications into recreational products. The use of etomidate has transitioned from emergency intubation to being inhaled by teenagers under the assumption that it's a harmless vape. Clinicians will identify the signs associated with potential effects of hidden sedation and, likewise, need to recognize the signs of adrenal suppression as they relate to the use of etomidate, particularly when naloxone does not return the patient to consciousness. Public health agencies must have better monitoring systems and education campaigns to adequately inform the public about space oil and other similar substances. In addition, providers must understand how etomidate works and its potential benefits to the patient.