|Suicide method ratings|
|Preparation and administration (5)||5|
|Speed of effect (5)||4|
|Safety to others (5)||5|
|Total score (50)||44|
Pentobarbital (trade name: Nembutal) is a drug from the barbiturate class. It was widely used during the 1940s and 1950s as a sleeping pill (i.e. hypnotic) or anti-anxiety drug (i.e. sedative). Unlike modern sleeping pills, Nembutal is highly lethal in overdose. Because it is very reliable and brings about peaceful death, it is one of drugs of choice for assisted suicide and capital punishment. Nembutal is used by euthanasia organizations in the United States (Oregon Death With Dignity Act), Switzerland (Dignitas) and The Netherlands.
Since it was so easy to overdose on Nembutal (whether accidentally or intentionally), it was almost universally taken off the market and replaced by safer sleeping pills, primarily benzodiazepines. For instance, Nembutal was removed from the Australian prescribing schedule in 1998. However, Nembutal remains in use by veterinary surgeons in order to euthanase bigger animals in most countries. Many people were successful in obtaining veterinary Nembutal for their suicide. The famous American actress Marilyn Monroe supposedly used Nembutal to end her life.
The brand name "Nembutal" was coined by Dr. John S. Lundy, who started using it in 1930, from the structural formula of the sodium salt—Na (sodium) + ethyl + methyl + butyl + al (common suffix for barbiturates). Nembutal is trademarked and manufactured by the Danish pharmaceutical company Lundbeck, and is the only injectable form of pentobarbital approved for sale in the United States.
Comparison to other methods
Nembutal is a proven, reliable drug that brings about a peaceful death. Almost no failures are known, despite large statistics (for example, the Swiss euthanasia organisation Dignitas reported 840 exits with no single failure). There are however reports on seemingly slow or painful deaths with Nembutal in capital punishment, although this may be due to poor quality of the drug from compounding pharmacies given intravenously rather than orally.
Nembutal is supposedly very difficult to obtain, as its sole remaining human use in most of the world is in liquid form for use as a sedative and anesthetic in hospitals. In Europe it is even more scarce than in the US. Because of this, no brick-and-mortar or mail-order pharmacy sells Nembutal; any such site that claims to do so is likely fake. Also, veterinary Nembutal is a liquid and not in pill-form, which means that it has a shorter shelf life. On the other hand, Seconal (secobarbital), a short acting barbiturate that is as powerful as Nembutal if not more powerful, is still available in capsule form in the USA and probably the UK. However, it is very rarely, if ever, prescribed. Nembutal has a bitter taste that require the use of anti-emetics to prevent vomiting when given orally at high dosages.
As a practical matter, Nembutal can still be obtained by those who have a few (or several) hundred dollars and knowledge of what supplier to ask. Specifically, the Peaceful Pill Handbook has a chapter, Obtaining Nembutal, with lists of trusted suppliers; updates to this list are made available to those who subscribe to the digital edition of the book. Availability changes rapidly though, and it is easy to be scammed.
There are a few views available on the lethal dose, all held by medical professionals. They are illustrated below.
- Dr. Nitschke in his The Peaceful Pill Handbook states, "Administration is a matter of dissolving ~10 gm of the powder in ~50 ml of water and drinking. . . . . If the powder is analyzed to be pure, and if ingested in the recommended amounts, Chinese Nembutal powder will (not might) lead to a reliable and peaceful death. . . . . The minimum lethal dose is 6 gms. If the substance is pure, a purchase of 25 gm of 95% pure soldium pentobarbital is more than enough for two adults."
- In The Netherlands, doctors who offer to help with hastening death, provide a drink with 9 grams of pentobarbital or secobarbital.
- The research committee of Dr. Admiraal, belonging to a Dutch euthanasia group, deemed that nobody has ever woken up after ingestion of 6 grams of a barbiturate if not tolerant to the drug, provided no vomiting occurred.
- In the book Departing Drugs by Chris Docker and Cheryl Smith, it is suggested on page 64 that 3.5 grams are the lethal dose of secobarbital. Dr. Admiraal deems that 3.5 grams can not be considered as sufficient to be reliably lethal, but that 6 grams would definitely be the sufficient amount.
- There are reports that Dignitas uses a liquid solution with 15 grams of Nembutal, probably as crushed tablets, dissolved in ~50 ml tap water.
Nembutal Sodium Solution and Powder
The most easily obtainable form today is vials of Nembutal Sodium Solution (pentobarbital sodium injection), a sterile solution for intravenous or intramuscular injection, typically used for animal anaesthesia or euthanasia. Each mL contains pentobarbital sodium 50 mg or 100 mg, in a vehicle of approximately propylene glycol, 40%, alcohol, 10% and water for injection, to volume. The pH is adjusted to approximately 9.5 with hydrochloric acid and/or sodium hydroxide. The range of actual pentobarbital sodium in a vial may vary between 3 g to 15 g, although 6 g seems common. The containers come in a clear vial typical for sterile solutions, and should have an untouched protective metal cap if unopened, and be labelled clearly with due date. Dignitas also use some sort of solution, albeit with a higher concentration. The solution may be taken intravenously, for very quick effect as in capital punishment, or orally, see below.
Nembutal Sodium is a short-acting barbiturate, chemically designated as sodium 5-ethyl-5-(1-methylbutyl) barbiturate. This is one of the reasons for being more suitable for suicide than longer-acting barbiturates such as phenobarbital.
Nembutal has also been reported to be available on the black market, particularly from China, in powder form. The purity of this powder is debated, see The Peaceful Pill Handbook. In Australia, a group of seniors have reportedly synthesised Nembutal on their own, using layman knowledge only, details of which can be found on YouTube. Site says that the video has been removed and the client's account closed.
As far as the authors of this wiki are aware, there were a few reports from alt.suicide.methods members, who said to have purchased liquid pentobarbital sodium in Mexico. This is also backed by the book of Dr. Nitschke, The Peaceful Pill Handbook, which features an extensive part about how to make a successful journey to Mexican cities in order to buy Nembutal. We will do our best to bring this section and post parts of it in this page along with people's reports from there.
- See a video report of one travel published on YouTube: here. Video no longer available 5/2/18
- There are possible plans to close a Mexican source. URL not found 5/2/18
- A report by someone who went to Mexico: it may be not that easy! Read it here.
- Some more information from the New York times.
There are also reports of black market Nembutal powder available by mail from China. Virtually all exposed sellers of Nembutal online are scams however! Beware! There are numerous reports in literature and on the internet from people being scammed substantial amounts from these so-called resellers, which often claim affiliation with Dr Nitschke or other authorities. These channels should not be sought. The state of availability of Nembutal from Darknet vendors has not really been reported anywhere yet, although it may be a possibility.
Barbiturates in general
The barbiturates are non-selective CNS depressants which are primarily used as sedative hypnotics and also as anticonvulsants in subhypnotic doses. The barbiturates and their sodium salts are subject to control under the Federal Controlled Substances Act in the US. Specifically, pentobarbital is a Schedule II controlled substance in the US whose illegal possession is punishable by one year in prison for a first-time drug offender, pursuant to Template:Usc. Most other countries have similar legislation for importing or possessing Nembutal.
Barbiturates are substituted pyrimidine derivatives in which the basic structure common to these drugs is barbituric acid, a substance which has no CNS activity (thus, barbituric acid alone would not be lethal). CNS activity is obtained by substituting alkyl, alkenyl, or aryl groups on the pyrimidine ring.
Mechanism of action
Barbiturates have direct effects on the benzodiazepine-GABA-a-chloride receptor complex in enhancing chloride flux, hyperpolarisation of the membrane, and neural inhibitory effects. As opposed to benzodiazepines, barbiturates do not only exert their inhibitory effect through the GABA receptors, but they also open independently more ion channels for chloride influx through the cell's membrane. That is why their inhibitory impact on the CNS is so severe. Barbiturates shut down the reticular formation in the brain, i.e. the neural pathways in the brain.
Tolerance and withdrawal
The prolonged use of barbiturates leads to tolerance. Also, cross-tolerance between barbiturates and benzodiazepines can be presented, since both drugs act through the GABA receptors. Hence, it is suggested that a period of 3–4 weeks of withdrawal can reverse the tolerance and this process is indeed needed for having one's attempt be a reliable one. As with all intoxication procedures, it is recommended that all consumption of medications that do not affect judgement be stopped some time in advance to drug ingestion, as well as consumption of alcohol and narcotics. Anti-psychotics have been mentioned as one confounding factor in failed or prolonged attempts, according to The Peaceful Pill Handbook.
Ingestion of the Nembutal Cocktail
Nembutal, unlike other lethal drugs, may not require any additional drugs. Only anti-emetic drugs must be taken in advance, in order to prevent any vomiting from occurring. This has been partially endorsed by experts in administration of the death penalty, whereby a pure barbiturate method has been deemed less painful and more successful than prior 3-drug approaches and newer concoctions involving e.g. Midazolam (in the traditional 3-drug approach, a barbiturate was one of the components). There have, however, been reports of less successful attempts, the cause of which have been debated. The use of pentobarbital-only has also been called into question by some experts on capital punishment.
Caveats and comparisons with animal euthanasia
However, experts in human anaesthesia have pointed out that pentobarbital, while an anaesthetic, is not a full analgesic. As such, coadministration of an appropriate analgesic may be advisable to completely eliminate risk of perceived pain, although reports of adverse events have been sparse. Suggestions for analgesics seem unclear at this time, perhaps a low-moderate dose opioid could be an option. The US Death with Dignity homepage mentions a mix of phenobarbital, choral hydrate, morphine sulfate and ethanol as a less expensive option to secobarbital. These additions are possibly due to phenobarbital being slower acting. In veterinary euthanasia, a two step approach is favoured, whereby a sedative such as propofol is given prior to an IV pentobarbital dose. Oral administration is recommended only as a fallback. This method may differ slightly in effect from oral human consumption in that death occurs almost immediately, and perhaps by cardiac effects rather than respiratory depression. In the recorded events of adverse events where IV pentobarbital was used for capital punishment, the likely cause was contaminated pentobarbital from a compounding pharmacy, something which should pose a small risk when taken orally. The fact that capital punishment experts have pointed out possible weaknesses in a pentobarbital-only ingestion warrants further investigation. Reports from Dignitas, which rely on Nembutal only, are encouraging however.
Some people with neurodegenerative disorders (MS, ALS) or inborn/acquired disabilities of the nervous system (autism, schizophrenia, Down's syndrome) have alterations to the functioning of the GABA system. It is not known how they respond to Nembutal, although, again, Dignitas reports are encouraging.
|Antiemetic drugs must be taken beforehand||See wiki book on antiemetics.|
|Liquid pentobarbital (Nembutal), either pure sterile solution or powder dissolved in small amount of water/applesauce.||6-12 grams (see discussion on lethality)|
|Analgesic (optional, possibly opioid, not discussed much in literature)||Low-moderate dose (Nembutal should have main CNS effect).|
Potentiating the cocktail and masking the taste
- 1-2 grams of Phenytoin (Dilantin) will potentiate the cocktail according to Dr Nitschke and veterinary sources. However, veterinarians have raised warnings that phenytoin cardiotoxic effects may come into play prior to the barbiturates full anaesthetic effect, and may therefore cause unwanted pain.
- It is usually recommended to drink some alcohol immediately after (not prior) to the Nembutal ingestion to potentiate its effect and mask the very bitter taste.
- Eating a big meal prior to or after the drug ingestion is not recommended to reduce chances of slow drug absorption or vomiting. Dignitas offers clients chocolates to deal with the bitter taste of the drug.
Time To Death
Experience in The Netherlands has learned that after ingesting 9 grams of either pentobarbital or secobarbital, death generally occurs within two hours (see the tables below).
- Time to death after oral ingestion of 9 grams pentobarbital (102 cases) or secobarbital (21 cases)
Time to death data in the Dutch euthanasia group: 123 cases from A. Horikx, staff member of the Royal Dutch Pharmaceutical Society.
|Time To Death||Number of
|0–15 minutes||39 people (32%)|
|16–30 minutes||40 (33%)|
|30–60 minutes||21 (17%)|
|1–2 hours||9 (7%)|
|Euthanasia by doctor after > 2 hours waiting||9 (7%)|
|Unknown time||5 (4%)|
- Time to death after oral ingestion of 10-12 grams pentobarbital (261 cases)
Similarly to the table displayed above, the following table (mentioned in Guide to a Humane Self-Chosen Death) provides the time to death as reported by the right-to-die organization "Exit deutsche Schweiz" (which literally translates as Exit German Switzerland).
|Time To Death||Number of
|0–15 minutes||70 people (27%)|
|16–30 minutes||115 (44%)|
|30–60 minutes||44 (17%)|
|1–2 hours||11 (4%)|
|2–12 hours||20 (8%)|
|> 12 hours||1 (0.4%)|
A pentobarbital overdose is an amount taken in excess of that which is medically recommended. Two to ten grams can cause death. CNS and respiratory depression which may progress to Cheyne-Stokes respiration, areflexia, constriction of the pupils to a slight degree (though in severe poisoning they may show paralytic dilation), oliguria, tachycardia, hypotension, lowered body temperature, and coma. Typical shock syndrome (apnea, circulatory collapse, respiratory arrest, and death) may occur.
In extreme overdose, all electrical activity in the brain may cease, in which case a "flat" EEG normally equated with clinical death cannot be accepted. This effect is fully reversible unless hypoxic damage occurs. Consideration should be given to the possibility of barbiturate intoxication even in situations that appear to involve trauma.
Complications such as pneumonia, pulmonary edema, cardiac arrhythmias, congestive heart failure, and renal failure may occur. Uremia may increase CNS sensitivity to barbiturates. Differential diagnosis should include hypoglycemia, head trauma, cerebrovascular accidents, convulsive states, and diabetic coma.