Review of Protocols and Substances for Euthanasia and Assisted Suicide

The practice of assisted suicide, also referred to as euthanasia and assisted suicide (EAS) or medical assistance in dying (MAiD), is based on a sophisticated pharmacological rationale aimed at transforming the act of causing death into a standardized medical procedure. Although the legal framework varies from one country to another, their protocols for PAS use similar methods and substances designed to ensure a rapid progression toward unconsciousness followed by death.

By Agnès Certain and members of the Association of Conscious Pharmacists (l’Association Pharmaciens en Conscience),[i] in collaboration with Yeram Jeon of the European Centre for Law and Justice (ECLJ).

I. A pharmacological triad of substances, methods, and effects

Modern EAS protocols are structured around three major categories of substances, each fulfilling a distinct pharmacological role to ensure the effectiveness of the procedure.

1. Barbiturates and sedative-hypnotic drugs: inducing coma

The first step consists of inducing a deep and irreversible loss of consciousness (a coma) and slowing respiration.

• Substances used: Physicians favor barbiturates such as pentobarbital, secobarbital, and thiopental, or general anesthetics such as doses of propofol far higher than those ordinarily used for medical purposes.
• Effects: These substances inhibit neuronal activity and depress the respiratory center located in the medulla and brainstem.
• Dosage and administration: In assisted suicide, the patient generally ingests a liquid solution containing between 9,000 and 15,000 milligrams of pentobarbital or secobarbital. For euthanasia, the physician directly injects a high dose of thiopental or propofol (1,000 mg) intravenously (IV), producing an almost immediate coma.

2. Neuromuscular blockers (paralytic agents): respiratory arrest

Once the patient has been placed in a deep coma, a paralytic agent will be administered to ensure the cessation of vital functions through oxygen deprivation. Without prior sedation, death would occur through suffocation while the person remained conscious.

• Substances used: The most common agents used are rocuronium, pancuronium, and cisatracurium.
• Effects: These substances block nerve transmission to the muscles, including the diaphragm, thereby stopping any attempt to breathe; the heart eventually stops from lack of oxygen.

3. Adjuvants: other drugs for “comfort and optimization”

To facilitate the procedure and prevent complications, additional medications may be administered beforehand.

• Antiemetics: Drugs such as metoclopramide or ondansetron are administered about thirty minutes beforehand to prevent vomiting, especially in cases involving oral ingestion of massive doses, thereby avoiding expulsion of the substances and enhancing their lethal effect.
• Benzodiazepines: Midazolam or diazepam are often used before the lethal procedure begins in order to reduce patient anxiety.
• Local anesthetics: Lidocaine may be administered to reduce local pain during injection of the lethal agents.

II. Protocols in countries that have decriminalized euthanasia and/or assisted suicide

Although all protocols are based on a combination of anesthetic/paralytic/adjuvant agents, they vary from country to country.

Netherlands and Belgium

In the Netherlands and Belgium, euthanasia by physician-administered injection is the most common practice. Assisted-suicide protocols are also available, including ingestion of a lethal drink by a person capable of doing so independently.

• Typical protocol: After administering midazolam and lidocaine to reduce anxiety and pain respectively, the physician injects 2,000 mg of thiopental or 1,000 mg of propofol to induce coma. Once coma is confirmed, a massive dose of paralytic agent (100–200 mg of rocuronium) is administered.
• Statistics: More than 99% of cases reported in the Netherlands use this combined barbiturate-paralytic method.

Canada (MAiD) — and potentially Australia (Victoria and Western Australia) if the patient cannot ingest a drink

Canada has developed a highly standardized approach to MAiD.

• The standard “kit:” In nearly 98% of cases, the standard IV protocol includes midazolam (10 mg), propofol (1,000 mg), and rocuronium (200 mg); lidocaine may also be added as a local anesthetic.
• Effectiveness: With this combination, death generally occurs within a median time of nine minutes.

United States (Oregon, Washington), Switzerland, Australia (Victoria, Western Australia) (Assisted Suicide)

In these jurisdictions, the legal framework often requires the patient to perform the final act personally.

• Oral ingestion: After taking an antiemetic thirty minutes beforehand, the patient drinks a mixture of barbiturates (9,000 to 15,000 mg of secobarbital or pentobarbital) and a sweet juice. Coma occurs within a few minutes, followed by respiratory arrest approximately half an hour later.
• Limitations on physician assistance: In Oregon, the physician’s role ends after prescribing the drugs. In Switzerland, a physician must prescribe the substance, but the act is supervised by nonprofit organizations.

Compared with legal executions by lethal injection, which add a third substance to stop the heart (potassium chloride or bupivacaine), euthanasia and assisted suicide produce deep coma followed by respiratory arrest due to oxygen deprivation. Critics often note that the physiological processes are fairly similar.

III. Complications and risks

EAS is not always a simple or incident-free process. Investigations show significant variability in results:

• Failures of oral assisted suicide: Approximately 15% of patients experience complications such as vomiting, convulsions, or even regaining consciousness after drinking the mixture.
• Unpredictable delays: While injection is rapid, the oral route is uncertain. Around 33% of deaths by ingestion take more than one hour, and in 7.6% of cases the process may last more than six hours.
• Uncertainty regarding pain: The use of paralytic agents raises the issue of “accidental awareness.” If sedation is insufficient, the patient could feel the burning pain of certain substances or the sensation of suffocation without being able to show any sign of distress because of muscular paralysis.
• Ineffectiveness of opioids: Opioids alone (such as morphine) are not recommended for euthanasia because they do not guarantee a rapid or predictable death, sometimes leading to a prolonged process of dying lasting from one to six hours. 

IV. Conclusion: a standardized yet fallible practice

In summary, decriminalized euthanasia and assisted suicide rely on medical protocols using powerful anesthetic and paralytic agents. Although these protocols are intended to produce a rapid and painless death, evidence from jurisdictions where they are practiced reveals significant uncertainties: notable complication rates, unpredictable survival duration, and potentially long and distressful periods of agony linked to the physiological variability of induced death. EAS differs fundamentally from palliative care in its deliberate intention to bring vital functions to an immediate and reliable end.

References

• Chaar, B., & Isaac, S. (2017, October 20). Euthanasia drugs: What is needed from medications for assisted deaths? ABC News. https://www.abc.net.au/news/2017-10-20/assisted-dying-what-is-need-from-drugs-for-voluntary-euthanasia/9069896
• Dignitas (non-profit organisation). (2025, January). In Wikipedia. https://en.wikipedia.org/wiki/Dignitas_(non-profit_organisation)
• Human Rights Watch. (2006, April 23). So long as they die: U.S. states negligent in use of lethal injections. https://www.hrw.org/sites/default/files/reports/us0406webwcover.pdf
• Oregon Health Authority, Public Health Division. (2020, February 25). Oregon Death with Dignity Act: 2019 data summary (Year 22 report). https://www.oregon.gov/oha/PH/ProviderPartnerResources/EvaluationResearch/DeathwithDignityAct/Documents/year22.pdf
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• Riley, S. (2017). Navigating the new era of assisted suicide and execution drugs. Journal of Law and the Biosciences, 4(2), 424–434. https://doi.org/10.1093/jlb/lsx028
• Royal Dutch Medical Association (KNMG) & Royal Dutch Pharmacists Association (KNMP). (2012). KNMG/KNMP guidelines for the practice of euthanasia and physician-assisted suicide. https://derechoamorir.org/wp-content/uploads/2018/09/2012-guia-eutanasia-colegio-medicos-pbajos.pdf
• Stukalin, I., Olaiya, O. R., Naik, V., Wiebe, E., Kekewich, M., Kelly, M., Wilding, L., Halko, R., & Oczkowski, S. (2022). Medications and dosages used in medical assistance in dying: A cross-sectional study. CMAJ Open, 10(1), E19–E26. https://doi.org/10.9778/cmajo.20200268
• Worthington, A., Finlay, I., & Regnard, C. (2022). Efficacy and safety of drugs used for assisted dying. British Medical Bulletin, 142(1), 15–22. https://doi.org/10.1093/bmb/ldac009
• Jeon Y., Substances and Protocols in Euthanasia and Assisted Suicide, Legal Research Intern, ECLJ, submitted 5 feb 2026

[i] Association Pharmaciens en Conscience: website