Do we know enough about euthanasia drugs?

Alex Schadenberg
Executive Director, Euthanasia Prevention Coalition

Manuela Callari reported in an article published by Medscape on March 13, 2025 that we don't know enough about assisted dying drugs. Callari interviewed several physicians who are doing euthanasia and a doctor who does palliative care research.

Callari begins the article by stating:

The medical community is accustomed to rigorous standards for drug development and approval. But in the context of assisted dying, there is a surprising and persisting lack of robust scientific data.

Steven Pleiter

Callari interviews Steven Pleiter the former managing director of the Dutch Center of Expertise for Euthanasia (Euthanasia clinic) who states:

“It’s very hard to do scientific research with regard to the usage of drugs for euthanasia. If you apply euthanasia, you want to be successful, and you can’t use any other drugs than the drugs we know work,”

“But the evidence is based on years and years of experience.”

Claud Regnard, MD, a retired palliative medicine consultant in the United Kingdom told Callari that:

“The amount of evidence supporting the use of these drugs is astoundingly small,

 “The last study looking at efficacy and side effects was published 25 years ago, using data from 10 years earlier.”

Dr Claud Regnard

Callari reported that unlike other areas of medicine, assisted dying has largely escaped rigorous scientific evaluation. He reported Regnard as stating:

“You wouldn’t allow this in any way with any other sort of drugs,” Regnard said. In a 2022 study, he found that drugs used for assisted dying have not undergone the usual level of scrutiny.

The pharmacokinetics and pharmacodynamics of these drugs at high doses remain poorly understood. “We extrapolate from therapeutic doses, but we have no proper data on what happens at lethal doses,” Regnard said. "That's not science — that's guesswork.”

Collari explained that:

Euthanasia is when a doctor directly ends the life of a patient, while assisted dying is when a doctor provides the means for them to end their own life.

(Collari should use the term assisted suicide rather than assisted dying. Assisted dying is often used for both euthanasia and assisted suicide.)

Collari reported Regnard as stating:

He said most jurisdictions, like Switzerland, the Netherlands, Belgium, Canada, and Australia, do not systematically collect or publish data on assisted dying drug efficacy, mechanisms, and complications. “Oregon is the only jurisdiction providing some transparency, but even their data is severely incomplete,”

Collari continues:

The Netherlands, one of the first European countries to legalize euthanasia and assisted dying, has developed guidelines on their implementation, now in their third edition.

Pleiter explains how euthanasia is done in the Netherlands:

For euthanasia, the standard Dutch protocol involves an initial injection of thiopental or propofol at doses several times higher than those used in general anesthesia to induce a deep coma. This is followed by administering a neuromuscular blocking agent such as rocuronium, atracurium, or cisatracurium in doses sufficient to cause complete paralysis and eventual death. “Most people die after the coma-inducing drug because it’s such a high dose,”  

“The patient will die within seconds. It’s very rapid.”

We know that the patient does not die within seconds in Oregon, where the Oregon 2023 assisted suicide report indicates that the longest time of death in 2023 was 137 hours. Collari then explains how assisted suicide is done in Switzerland

In Switzerland, a commonly used drug is the fast-acting barbiturate sodium pentobarbital, according to documentation provided by Dignitas to Medscape Medical News. This is usually taken orally or, in some cases, via a gastric tube or intravenously. The documentation did not include specific data on this drug’s efficacy or complication rates. Dignitas declined a request for an interview.

None of these drugs are approved for euthanasia and there is no standardized protocol. Regnard explains:

There is no standardized global approach to drug selection and dosing for either euthanasia or assisted dying, and the process is mainly empirical. “There isn’t a single drug regulatory authority anywhere in the world that has assessed and approved assisted dying drugs [in the doses required for this purpose],”

Instead, these medications are approved for indications such as anesthesia or epilepsy, and their use in euthanasia or assisted dying falls under off-label prescribing. Physicians rely on guidelines established by medical associations, expert committees, and historical clinical practice for their use.

Since Oregon is the only jurisdiction that collects data on the use of assisted dying drug coctails, Regnard provides an analysis of the Oregon data:

In a 2023 report from the US state of Oregon, 74% of complication data were missing. Of the available data, 9%-11% of patients experienced complications, including vomiting, aspiration, agitation, and seizures. “In some cases, patients regained consciousness after ingesting a lethal dose,” he said.

The time to death also varies widely — from minutes to several hours. Factors such as the specific drugs used, the route of administration, and individual patient factors can all play a role. In some cases, death may occur rapidly, while in others it may take longer. This variability can be distressing for both the patient and their loved ones, particularly if they expect a swift and peaceful death, he argued.

Article: Death by assisted suicide is not what you think it is. (Link).

Pleiter agrees that the evidence concerning the safe use of these drugs and  evidence concerning complications is anecdotal. Pleiter's comments actually reinforce the research by Regnard. Regnard continues by pointing out that:

The lack of reliable data also raises concerns about informed consent. Patients are often reassured that their death will be peaceful, but without comprehensive studies, how can such promises be guaranteed?

Regnard asks:

“How can you get informed consent from a patient when the data isn’t there?”

“Until they produce the data, the data is purely anecdotal. We wouldn’t tolerate that level of uncertainty in palliative care, so why are we tolerating it here?”

Collari reports that Pleiter argued that, based on experience, the Dutch protocols work:

Pleiter noted that euthanasia has been practiced in the Netherlands for two decades, with consistent guidelines that have undergone only minor revisions. More than 100,000 patients have undergone the procedure using these established protocols. The core drug dosages have remained mostly unchanged. “When the correct drugs are administered at the right doses, there are no issues, and the outcome is always certain,” he said. Having overseen almost 5000 cases, Pleiter said he has never encountered complications.

But Mario Riccio, MD, a retired anesthetist, current advisor of the Luca Coscioni Association, an assisted dying group in Italy told Collari

“Even with precautions, the process is not always smooth. There can be moments of discomfort and unexpected reactions — things we simply cannot control. But for someone whose suffering is so excruciating that he is determined to die, minor complications are completely surmountable.”

There is no evidence concerning the use of euthanasia and assisted suicide poison coctails. 

Links to more articles on this topic:

• Death by assisted suicide is not what you think it is (Link). 
• Assisted suicide: Proceed with caution (Link). 
• Assisted suicide is the wrong prescription (Link). 
• Assisted suicide. It's not that simple (Link). 
• Assisted suicide deaths are not what you think they are (Link). 
• Assisted suicide is neither painless nor dignified (Link).