Lethal injection

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The lethal injection room at San Quentin State Prison, completed in 2010

Lethal injection involves injecting a person with a fatal dose of drugs to cause death. The main applications of lethal injections are euthanasia and capital punishment. As a method for capital punishment, lethal injection gained popularity in the twentieth century as a form of execution meant to supplant methods – such as electrocution, hanging, firing squad, gas chamber, or decapitation – that were considered to be less humane. It is now the most common form of execution in the United States; in 2005, every American execution was conducted by lethal injection.

However, the humaneness of lethal injection as a process of execution has been debated, with opponents citing reports of prolonged, apparently painful deaths. While proponents agree that a peaceful, painless death is the desired outcome, no satisfactory alternative has been proposed and adopted. Those who regard the death penalty per se as problematic argue that there is no acceptable way to kill another human being, and thus no acceptable method can be developed. Clearly, the most ideal situation is one in which the death penalty is not needed as all people live with respect for the lives of others and so do not commit capital crimes.

Lethal injection has also been used in euthanasia to facilitate death in patients with terminal or chronically painful conditions. In this case, the argument involves not so much whether the death is quick and painless, since the patients have already experienced prolonged suffering, but rather the ethical and legal issues involved in assisting the suicide of another. To date, lethal injection has been chosen as the most reliable method to accomplish such "mercy killings."


Did you know?
Lethal injection was first proposed as a cheaper and "more humane" method of execution than hanging
Usage of lethal injection for the death penalty by jurisdiction in the United States in 2021
Color key: ██ Jurisdiction uses only this method ██ Jurisdiction uses this method primarily but has other methods Without the death penalty ██ Jurisdiction once used this method, but no longer does ██ Jurisdiction once adopted this method, but never actually used it ██ Jurisdiction has never adopted or used this method

The concept of lethal injection was first proposed in 1888 by Julius Mount Bleyer, a New York doctor who praised it as being cheaper and more humane than hanging. The idea did not catch on and New York introduced the electric chair instead.[1] Bleyer's idea, however, was never used.

Nazi Germany's T-4 Euthanasia Program used lethal injection, with various drug combinations that differed from the modern method, as one of several methods to destroy "life unworthy of life."[2]

In 1977, Jay Chapman, Oklahoma's state medical examiner, proposed a new, "more humane" method of execution, known as Chapman's Protocol. He proposed that

An intravenous saline drip shall be started in the prisoner's arm, into which shall be introduced a lethal injection consisting of an ultra-short-acting barbiturate in combination with a chemical paralytic.[3]

Former gas chamber, converted to lethal injection chamber.

After being approved by anesthesiologist Stanley Deutsch, the method was adopted by Oklahoma under Title 22, Section 1014A. Since then, 37 of the 38 states using capital punishment have introduced lethal injection statutes, in nineteen of which lethal injection is the only method of execution allowed.[3] The sole exception is Nebraska, which continues to electrocute the condemned. On December 7, 1982, Texas became the first state to use lethal injection as a capital punishment for the execution of Charles Brooks, Jr.[4] It is now the most common form of execution in the United States; in 2005, every American execution was conducted by lethal injection.[3]

The People's Republic of China began using this method in 1997, Guatemala in 1998, and the Philippines in 1999; multiple other countries have also legally, though not practically adopted the method.

Lethal injection has also been used in euthanasia to facilitate death in patients with terminal or chronically painful conditions. Both applications use similar drug combinations.

Procedure in US executions

Execution by lethal injection follows a strict procedure, as do all occasions in which the death penalty is carried out. The condemned is fastened on the execution table, and two intravenous cannulae or "drips" are inserted into each of the prisoner’s arms. Though only one is used for the execution, the other is reserved as a backup in case the primary line fails. The intravenous injection is usually a sequence of compounds, designed to induce rapid unconsciousness followed by death through paralysis of respiratory muscles and/or by inducing cardiac arrest through the depolarization of cardiac muscle cells.

The execution of the condemned in most states involves three separate injections. The first injection, sodium thiopental, is done to render the offender unconscious. The next injection consists of pancuronium or Tubocurarine to stop all muscle movement except the heart. This causes muscle paralysis, collapse of the diaphragm, and would eventually cause death by asphyxiation. The final injection of Potassium chloride is used to stop the heart from beating, and thus cause death through cardiac arrest. The drugs are not mixed externally as that can cause them to precipitate.

The intravenous tubing leads to a room next to the execution chamber, usually separated from the subject by a curtain or wall. Typically a technician trained in venipuncture inserts the cannulae, while a second technician, who is usually a member of the prison staff, orders, prepares, and loads the drugs into an infusion pump. After the curtain is opened to allow the witnesses to see inside the chamber, the condemned person will then be permitted to make a final statement. Following this, the warden will signal for the execution to commence, and the executioners, either prison staff or private citizens depending on the jurisdiction, will then activate the infusion pump which mechanically delivers the three drugs in sequence. During the execution, the subject's cardiac rhythm is monitored. Death is pronounced after cardiac activity stops. Death usually occurs within seven minutes, although the whole procedure can take up to two hours. According to state law, if participation in the execution is prohibited for physicians, the death ruling is made by the state's Medical Examiner's Office. After confirmation that death has occurred, a coroner signs the executed individual’s death certificate.

Chemical components

The following drugs are a representation of a typical lethal injection as practiced in the United States for capital punishment.

Sodium thiopental

  • Lethal Injection dosage: 5 grams

Sodium thiopental, or sodium pentothal, is an ultra-short acting barbiturate, often used for anesthesia induction and for medically induced comas. The typical anesthesia induction dose is 3-5 mg/kg; a person weighing 200 pounds, or 91 kilograms, would receive a dose of about 300 mg. Loss of consciousness is induced within 30-45 seconds at the typical dose, while a lethal injection dosage of 5 grams - 14 times the normal dose - is likely to induce unconsciousness within 10 seconds.

Thiopental reaches the brain within seconds and attains a peak brain concentration of about 60 percent of the total dose in about 30 seconds. At this level, the subject is unconscious. The half-life of this drug is about 11.5 hours, and the concentration in the brain remains at around 5-10 percent of the total dose during that time.[5]

Pancuronium bromide

  • Lethal Injection dosage: 100 milligrams

Pancuronium bromide, or pavulon, is a non-depolarizing muscle relaxant or paralytic agent that blocks the action of acetylcholine at the motor end-plate of the neuromuscular junction. With the lethal injection dosage for pancuronium bromide of 100 milligrams, the onset of paralysis occurs in around 15 to 30 seconds, and the duration of paralysis is around 4 to 8 hours. Paralysis of respiratory muscles will lead to death in a considerably shorter time.

Potassium chloride

  • Lethal Injection dosage: 100 mEq (milliequivalents)

Typically, doctors give patients potassium when there is insufficient potassium, called hypokalemia, in the blood. When used in lethal injection, at a dosage of 100 mEq, bolus potassium injection affects the electrical conduction of the heart muscle. Elevated potassium, or hyperkalemia, causes the resting electrical activity of the heart muscle to be higher than normal. The lethal dosage causes the heart to malfunction and stop, resulting in death.

Euthanasia protocol

A machine that can facilitate euthanasia through heavy doses of drugs. The laptop screen leads the user through a series of steps and questions to ensure they are fully prepared. The final injection is then done by motors controlled by the computer.

Euthanasia can be accomplished either through oral, intravenous, or intramuscular administration of drugs. In individuals who are incapable of swallowing lethal doses of medication, an intravenous route is preferred. The following is a Dutch protocol for intravenous administration to obtain euthanasia.

First a coma is induced by intravenous administration of 1 g thiopental sodium, if necessary, 1.5-2 g of the product in case of strong tolerance to barbiturates. 45 mg of alcuronium chloride or 18 mg of pancuronium bromide is then injected. In severe hepatitis or cirrhosis of the liver, alcuronium is the agent of first choice.



Opponents of lethal injection believe that the practice is not actually humane as performed in the United States. They argue that the thiopental is an ultra-short acting barbiturate that may wear off creating an anesthesia awareness which may lead to consciousness and an excruciatingly painful death wherein the inmate is unable to express their pain because they have been rendered paralyzed by the paralytic agent.

Opponents point to the fact that sodium thiopental is typically used as an induction agent and not used in the maintenance phase of surgery because of its short acting nature. They also argue that the agent pancuronium bromide, which follows the injection of thiopental, not only dilutes the thiopental, but may also prevent the inmate from expressing pain.

Additionally, opponents argue that the method of administration is also flawed. Many believe that since the personnel administering the lethal injection lack expertise in anesthesia, the risk of failing to induce unconsciousness is greatly increased. Also, they argue that the dose of sodium thiopental must be customized to each individual patient, not restricted to a set protocol. Finally, the remote administration results in an increased risk that insufficient amounts of the lethal injection drugs may enter the bloodstream.

In total, opponents argue that the effect of dilution or improper administration of thiopental is that the inmate dies an agonizing death through suffocation due to the paralytic effects of pancuronium bromide and the intense burning sensation caused by potassium chloride.

Opponents of lethal injection as currently practiced argue that the procedure employed is entirely unnecessary and is aimed more towards creating the appearance of serenity and a humane death than an actually humane death. More specifically, opponents object to the use of Pancuronium bromide. They argue that its use in lethal injection serves no purpose, since there is no need to keep the prisoner completely immobilized since they are physically restrained.


In 2005, University of Miami researchers, in cooperation with an attorney representing death row inmates, published a peer-reviewed research letter in the medical journal The Lancet. The article presented protocol information from Texas and Virginia which showed that executioners had no anaesthesia training, drugs were administered remotely with no monitoring for anaesthesia, data were not recorded, and no peer-review was done. Their analysis of toxicology reports from Arizona, Georgia, North Carolina, and South Carolina showed that post-mortem concentrations of thiopental in the blood were lower than that required for surgery in 43 of 49 executed inmates, or 88 percent, and 21 inmates, or 43 percent, had concentrations consistent with awareness.[6] This led the authors to conclude that there was a substantial probability that some of the inmates were aware and suffered extreme pain and distress during execution.

The authors attributed the risk of consciousness among inmates to the lack of training and monitoring in the process, but carefully make no recommendations on how to alter the protocol or how to improve the process. Indeed, the authors concluded, "because participation of doctors in protocol design or execution is ethically prohibited, adequate anaesthesia cannot be certain. Therefore, to prevent unnecessary cruelty and suffering, cessation and public review of lethal injections is warranted."

Paid expert consultants on both sides of the lethal injection debate have found opportunity to criticize the Lancet article. Subsequent to the initial publication in the Lancet, three letters to the editor and a response from the authors extended the analysis. The issue of contention is whether thiopental, like many lipid-soluble drugs, may be redistributed from blood into tissues after death, effectively lowering thiopental concentrations over time, or whether thiopental may distribute from tissues into the blood, effectively increasing post-mortem blood concentrations over time. Given the near-absence of scientific, peer-reviewed data on the topic of thiopental post-mortem pharmacokinetics, the controversy continues in the lethal injection community and in consequence, many legal challenges to lethal injection have not used the Lancet article.

Cruel and unusual

On occasion, there have also been difficulties inserting the intravenous needles, sometimes taking over half an hour to find a suitable vein. Typically, the difficulty is found in patients with a history of intravenous drug abuse. Opponents argue that the insertion of intravenous lines that take excessive amounts of time are tantamount to be cruel and unusual punishment. In addition, opponents point to instances where the intravenous line has failed, or where there have been adverse reactions to drugs, or unnecessary delays during the process of execution.

On December 13, 2006, Angel Nieves Diaz was unsuccessfully executed in Florida using a standard lethal injection dose. Diaz was 55 years old, and had been sentenced to death for murder. Diaz did not succumb to the lethal dose even after 35 minutes, but did after receiving a second dose of drugs. At first a prison spokesperson denied Diaz had suffered pain and claimed the second dose was needed because Diaz had some sort of liver disease. After performing an autopsy, the Medical Examiner, William Hamilton, stated that Diaz’s liver appeared normal, but that the needle had been pierced through Diaz’s vein into his flesh. The deadly chemicals had subsequently been injected into soft tissue, rather than into the vein. Two days after the execution, Governor Jeb Bush suspended all executions in the state and appointed a commission “to consider the humanity and constitutionality of lethal injections.”[7]

A study published in 2007 in the peer-reviewed journal PLoS Medicine suggested that "the conventional view of lethal injection leading to an invariably peaceful and painless death is questionable."[8]

Posed alternatives

Many opponents claim that because death can be painlessly accomplished, without risk of consciousness, by the injection of a single large dosage of barbiturate, the use of any other chemicals is entirely superfluous and only serves to unnecessarily increase the risk of torture during the execution. Another possibility would be the use of a fast-acting narcotic, such as fentanyl, which is widely used for inducing anesthesia for the entire duration of a short operation. To prevent the "patient" waking up too soon, the injection could be repeated before the blood-level falls.



Supporters of the death penalty cite that the combination of a barbiturate induction agent and a nondepolarizing paralytic agent is used in thousands of anaesthetics every day. Many argue that unless anesthesiologists have been wrong for the last 40 years, the use of pentothal and pancuronium is safe and effective. The agent potassium is even given in heart bypass surgery to induce cardioplegia. Therefore, the combination of these three drugs to create a lethal injection is still in use today. Supporters of the death penalty speculate that the designers of the lethal injection protocols intentionally used the same drugs as used in every day surgery to avoid controversy. The only modification is that a massive coma-inducing dose of barbiturates is given.


Thiopental is a rapid and effective drug for inducing unconsciousness, since it causes loss of consciousness upon one circulation through the brain due to its high lipophilicity. Only a few other drugs, such as methohexital, etomidate, propofol, or fentanyl have the capability to induce anesthesia so rapidly. Supporters argue that since the thiopental is given at a much higher dose than for medically-induced coma protocols, it is effectively impossible for a patient to wake up.

The average time to death once a lethal injection protocol has been started is about 5-18 minutes.[9] Since it only takes about 30 seconds for the thiopental to induce anesthesia, 30-45 seconds for the pancuronium to cause paralysis, and about 30 seconds for the potassium to stop the heart, death can theoretically be attained in as little as 90 seconds. Given that it takes time to administer the drugs through an IV, time for the line to be flushed, time to change the drug being administered, and time to ensure that death has occurred, the whole procedure takes about 7-11 minutes. Procedural aspects in pronouncing death also contribute to delay and, therefore, the condemned is usually pronounced dead within 10 to 20 minutes of starting the drugs. Supporters of the death penalty say that a huge dose of thiopental, which is between 14-20 times the anesthetic induction dose and which has the potential to induce a medical coma lasting 60 hours, could never wear off in only 10 to 20 minutes.

Dilution effect

Death penalty supporters also refute the claim that the dose of pancuronium dilutes the pentothal dose. Instead, supporters argue that pancuronium and thiopental are commonly used together in surgery every day and if there were a dilution effect, it would be a known drug interaction.

Supporters of the death penalty argue that even if the 100 mg of pancuronium directly prevented 500 mg of thiopental from working, there would be sufficient thiopental to induce coma for 50 hours. In addition, if this interaction did occur, then the pancuronium would be incapable of causing paralysis.

Posed alternatives

Amnesty International, Human Rights Watch, the Death Penalty Information Center, and other anti-death penalty groups, have not proposed a lethal injection protocol which they believe is more humane. Supporters of the death penalty argue that the lack of an alternative proposed protocol is testament to the fact that the humaneness of the lethal injection protocol is not the issue.

Regardless of an alternative protocol, some death penalty opponents have claimed that execution can be more humane by the administration of a single lethal dose of barbiturate. Many supporters of the death penalty, however, state that the single drug theory is a flawed concept. Terminally ill patients in Oregon who have requested physician-assisted suicide have received lethal doses of barbiturates. The protocol has been highly effective in producing a humane death, but the time to cause death can be prolonged. Some patients have taken days to die, and a few patients have actually survived the process and have regained consciousness up to three days after taking the lethal dose. In a Californian legal proceeding addressing the issue of the lethal injection cocktail being "cruel and unusual," state authorities said that the time to death following a single injection of barbiturate is approximately 45 minutes.[9] The position of death penalty supporters is that death should be obtained in a reasonable amount of time.


In Hill v. Crosby, decided June 12, 2006, the U.S. Supreme Court ruled that death-row inmates in the United States may challenge protocols used in the lethal injection process as potentially violating the Eighth Amendment's "cruel and unusual" punishment clause outside of a petition for a writ of habeas corpus. Clarence Hill had already exhausted all of his legal appeals through habeas corpus and filed a lawsuit claiming that lethal injection was a civil rights issue. The Supreme Court, in this ruling, did not decide whether lethal injection as currently practiced in the United States constitutes cruel and unusual punishment.[10][11]

The American Medical Association believes that a physician's opinion on capital punishment is a personal decision. Since the AMA is founded on preserving life, they argue that a doctor "should not be a participant" in executions in any form with the exception of "certifying death, provided that the condemned has been declared dead by another person."[12] The AMA, though, does not have the authority to prohibit doctors from participation in lethal injection, nor does it have the authority to revoke medical licenses, since this is the responsibility of the individual states. Typically, most states do not require that physicians administer the drugs for lethal injection, but many states do require that physicians be present to pronounce or certify death.


  1. Lethal injection in the USA Capital Punishment U.K. Retrieved April 16, 2023.
  2. Gitta Sereny, Into That Darkness: from Mercy Killing to Mass Murder, a study of Franz Stangl, the commandant of Treblinka (McGraw-Hill, 1974, ISBN 978-0070562905).
  3. 3.0 3.1 3.2 "I. Development of Lethal Injection Protocols So Long as They Die: Lethal Injections in the United States (Human Rights Watch, 2006). Retrieved April 16, 2023.
  4. Jonathan I. Groner, Lethal injection: a stain on the face of medicine British Medical Journal 325 (2002):1026–1028. Retrieved April 16, 2023.
  5. D.J. Morgan, G.L. Blackman, J.D. Paull, and L.J. Wolf, Pharmacokinetics and plasma binding of thiopental. I: Studies in surgical patients Anesthesiology 54(6)(Jun 1981): 468-473. Retrieved April 16, 2023.
  6. Leonidas G. Koniaris, et al., Inadequate anaesthesia in lethal injection for execution The Lancet 365(9468) (2005): 1412–1414. Retrieved April 16, 2023.
  7. Karen Voyles, AGov. Bush suspends executions The Gainesville Sun, December 15, 2006. Retrieved April 16, 2023.
  8. Anne Harding, Some executed US prisoners may have suffocated BMJ 334(7600) (2007}: 920. Retrieved April 16, 2023.
  9. 9.0 9.1 Kevin Bonsor, How Lethal Injection Works Howstuffworks. Retrieved April 16, 2023.
  10. U.S.: Supreme Court Allows Challenges to Lethal Injections HumanRightsWatch, June 11, 2006. Retrieved April 16, 2023.
  11. Hill v. McDonough Retrieved April 16, 2023.
  12. 9.7.3 Capital Punishment AMA Retrieved April 16, 2023.

ISBN links support NWE through referral fees

  • Battin, Margaret Pabst, and Arthur G. Lipman. Drug Use in Assisted Suicide and Euthanasia. Haworth Press, 1996. ISBN 1560248432
  • Kaufman-Osborn, Timothy V. From Noose to Needle: Capital Punishment and the Late Liberal State. Ann Arbor, MI: University of Michigan Press, 2002. ISBN 0472112910
  • Sarat, Austin. Lethal Injection and the False Promise of Humane Execution. Stanford University Press, 2022. ISBN 978-1503633537
  • Sereny, Gitta. Into That Darkness: from Mercy Killing to Mass Murder, a study of Franz Stangl, the commandant of Treblinka. McGraw-Hill, 1974. ISBN 978-0070562905

External links

All links retrieved April 16, 2023.


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