How does lethal injection work?

- asks Jim from Ohio

November 12, 2007

The U.S. Supreme Court is now closely assessing the answer to this question as they consider the constitutionality of a method of execution that’s used in all but one of 38 death penalty states.

Execution by lethal injection has largely replaced other forms of capital punishment, such as electrocution and the cyanide gas chamber, because it is seen as a more humane way of ending a life. Constitutional law states that capital punishment is only acceptable if it doesn’t violate the Eighth Amendment’s ban on cruel and unusual punishment. A person shouldn’t be aware of or able to sense any pain during the procedure. Lethal injection is thought to adhere to this policy because an initial drug is used to induce a state of unconsciousness where pain can no longer be registered. For the person being executed, subsequent injections that rapidly stop their breathing and heartbeat should occur without their sensing it.

According to the Death Penalty Information Center in Washington D.C., the protocol for lethal injection in most states involves a sequence of three shots that are delivered via intravenous drips inserted in each arm.

The first of the three injections is an anesthetic, sodium thiopental, which is a fast-acting barbiturate that depresses the activity of the central nervous system. This initial shot doesn’t serve as an analgesic (pain killer) that numbs pain nerves, but instead rapidly puts a person into a state of unconsciousness that’s theoretically deep enough to make pain undetectable. The drug amplifies the effect of GABA, a neurotransmitter that depresses brain activity, while also blocking the actions of an excitatory brain receptor, AMPA, which acts in many parts of the brain. The state of unconsciousness can be reached in as little as 30 seconds. A single dose of this anesthetic is intended to last throughout the last two injections to prevent any pain during the moments leading up to death (pronounced after the heart stops beating for a certain amount of time).

After the initial injection, the intravenous line is quickly flushed with saline, a neutral substance commonly used to push a drug into the bloodstream more quickly. Subsequently, pancuronium bromide is administered. It acts as a neuromuscular blocker, preventing a nerve messenger, acetylcholine, from communicating with muscles. The result is a complete muscle paralysis, which causes respiratory arrest since the diaphragm—a muscle imperative to pulling air into the lungs—stops working.

Following another saline flush is the final injection, potassium chloride. This last dosage of chemical floods the heart with charged particles that interrupt its electrical signaling, stopping it from beating. According to a 2002 study in the Journal of Forensic Science, the average length of time from the first injection to death is 8.4 minutes.

The dosage of each drug administered in lethal injection is supposed to be redundant, which means that the amount of chemical contained in each shot is lethal. For example, during surgeries, patients are normally given 100 to 150 milligrams (mg) of sodium thiopental, the initial anesthetic used in capital punishment, over a period of 10 to 15 minutes – while up to 5,000 mg are provided during executions. For pancuronium bromide, 40 to 100 micrograms per kilogram of body weight is normally given pre-operatively (to aid intubation) while a thousand times that amount is used for execution. When all three injections are used in executions, the aim is to put the person into a state of total unconsciousness before they die from a mix of respiratory and cardiac arrest.

Not only that, to ensure that the first injection reliably maintains a sedated state during the entire execution, an effective amount must constantly be in the blood system to prevent any chance of regaining awareness and, in turn, suffering, according to a study published this year in Public Library of Science Medicine. This is especially important when a person being executed could potentially be in a state that incapacitates them from physically showing discomfort while still experiencing it nonetheless. (See an article concerning the controversy over one Florida case in the St. Petersburg Times.)

Improper delivery of the anesthetic, either because an insufficient amount is administered or the IV is misplaced in the arm, is one of many aspects of lethal injections that poses a challenge to its public acceptance.

Researchers also have debated lethal injection. According to a 2005 letter in The Lancet, which looked at post-mortem toxicology reports of executions carried out in Arizona, Georgia, North Carolina and South Carolina, the blood concentrations of thiopental were low enough that 21 out of 49 executions (43 percent) had concentrations that allowed for a regaining of awareness.

This finding was disputed in the same issue by Jonathan Groner, its also gets quickly absorbed into fat and muscle tissue—even after death. When considering this and the manner in which the anesthetic is delivered (a ‘bolus’ injection of a high quantity, all at once) post-mortem blood samples cannot be a reliable measure of the amount of sodium thiopental that was circulating in the blood.

Another controversial aspect of lethal drug administration is that health professionals are not present during the procedure. Currently, doctors and nurses in the United States are banned by their professional organizations from participating in executions.

The reliability of painless lethal injection procedures will come up when the Supreme Court hears the constitutional challenges specific to the three-chemical protocol. This case, which will be argued early next year and should be decided by early next summer, is in response to an appeal by two Kentucky death row inmates who challenged the execution process. Their argument is based on the belief that the injection of the three-chemical cocktail inflicts unnecessary pain and suffering that could be avoided.


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Martin Jones says:

How can any way of murder, by the state or person, be ‘humane’. To kill a person who is defenceless and no threat to you is murder. A persons life should only be taken when that person is a direct threat to you or others.

jeff johnson says:

why are elephants grey?

jeff johnson says:

why are people tall?

david osborne says:

why are the prisoners killed via injection? why dont the prison executioners just shoot them like they did in world war 2? Do you feel pain when shot in the head because i would rather that personally than a needle 6 inches long in my arm 3 times and dying in a matter of 8.4 minutes why not die instantly with a quick shot in the head.

Me in Tennessee says:

In response to Martin Jones. I read that you stated that to kill a person who is defenseless is murder. I must ask at this point, have you ever had a family member raped and killed? They didn’t have a choice to appeal the decision made by their attacker, there is no plea bargain available for them or their families. The person who committed the act of violence knew full well what they were doing and what the outcome would be if they were caught and convicted. I myself believe it is inhumae to let them chose the way they will die. The family membes of their victims should chose this fate!

Reuben says:

I agree with Me in Tennessee. Once you have a family member killed or raped it’s a whole different story.

stuart says:

Firstly I dont see how two wrongs make a right anyone who murders or rapes or inflicts any sort of evil on another human being should be punished
for example a cold blooded pre meditated murder carried out by a person is clearly wrong so it makes no sence to then do the exact same thing to that person only its worse because their murder is pre meditated for several years and know exactly how they will die but becausae the state is carrying the process its deemed ok. the person they murdered would have had no idea until maybe they turned round to see a gun pointing at their head and then a split second later a bullet through the head. If capital punishment has to stay I dont see how they seem to find it difficult to find a humane method to murder the inmate. what the hell is wrong with putting the inmate out as though having an operation and then stop the body functions I personally think they want to make them suffer during the excution its bizarr that its legal to violently murder someone then be allowed home and get payed for it. ELECTROCUTION, POISON GAS, INJECTIONS, HANGING are all as wrong as the crime they are susposed to be punishing. thanks for reading

Stephanie says:

I think that lethal injection is too good for any murder. To kill a murder, first find out how they killed their victims, then kill them that way. if wanted to the family of the victim can even help kill them.

Stacey says:

THANK YOU! i have been looking for this information everywhere and wasn’t able to find it anywhere! you are a lifesaver!

Scott says:

Ok, first (Martin Jones) the reason he is no threat and “defenseless” is because they have restrained him… why? Because he is a dangerous KILLER! Duuh! Next, two wrongs don’t make a right, but “an eye for an eye” as the Bible says. Plus we are SUPPOSED to be a society of laws, right? And, as such, the Law (i.e. Police, Judges, lawyers, etc.) take care of the determination if a crime was comitted (investigation), determine who did the crime (trial – judges, lawyers, juries), and the punnishment for the crime(s) (things that are AGAINST THE LAW). If this society which follows the “rule of law” fails and the “rule of law” is allowed to be broken for one or some because of some judgement of “wrongness” of the law (instead of having the law changed), we descend into the state we are in now (where criminals get more consideration than those who have been wronged).
I, for one, believe in the death penalty. I also believe that someone sentenced to death should have all of 90 to 180 days *!AT MOST!* (from the date of sentencing to execution) to live. If we had a system that was that effecient, the death penalty would be a deterrant. As the system is now, there is no deterrance to it… what you get is “three hots and a cot” for the next 10, 20, 30 or more YEARS!!
My last thought…
“An eye for an eye!”

Scott says:

stuart, what, exactly would you like to do with people who commit murder (not manslaughter, MURDER)? I tell you what, you can build a prison cell in your basement and keep them there for “life”, how does that sound? Any one else that belives that an execution is murder, not punnishment can do the same.
I do not feel that way. I think that word “humane” is too good for a murderer, and the concept of making their death a “painless” one is just simply B.S.! Not to mention, a plain waste of money. A far, far simpler solution is to make a room out of stainless steel, shaped like a tub/shower with a lid on it, an automatic wash system, and a firearm with a bullet in it suspended with a remote trigger would be far less expensive, plus it can be reused (except the bullet of course) over, and over, and over, and over again, and again, and again. Awe, hell, you don’t even need the auto-wash system in it… Wouldn’t that be something to see (the look on the murderer’s face when they lead them into it and they see all that blood and brain matter splattered about)!

kyle says:

everyone is has been discussing this philosophically, allow me to enter factually…127 people who were on deathrow have been released since 1973 due to the introduction of DNA evidence, and proven cases of police coercion leading to false testimony. So the question in reality is this “are you okay with killing a couple of innocent people to eliminate murderers?” if yes, you are an idiot, if no, you are dealing with the cards you were dealt as best you can and i applaud your pragmatism.

Dan says:


Dan says:


Cassy says:

I think lethal injection has been the closest way to “humanely” killing a murderer. I keep an open-mind for both sides of the argument, but I have to say I still lean towards for the death penalty. The people who are on death row aren’t convicted of little crimes. I agree with Stephanie. I think the murdere should have done to them what they did to others. For all the religious people, the Bible says treat others how you would like to be treated. They murderer so they in return should be treated the same way as their victim was.

Heather says:

They don’t sick a 6″ needle in your arm 3 times. It’s a tiny IV line they set up prior, and put the drug in through the line, and after the first one (it numbs your body) you dont feel shit…pretty painless considering the bastard probably raped and tortured some innocent girl and then suffocated her to death.

I have no problem executing the vilest of society, nor am I moved by cruelty arguments over the methodology. I however disagree to the “pecking” order of punishments. The punishment the shoe bomber received which is life in the Colorado Super Max I consider far more appropriate as a deterrent and more effective as punishment than an easy exit at the end of a needle. Although the conditions at this and similar prisons aren’t well publicized, maybe they should. Criminals often describe prison sentences as badges of honor but Super Max prisons are one way streets and most criminals have no knowledge of what a “life” sentence can truly mean. I would guess if given a choice, most prisoners would opt for the needle over Super Max and as such I believe the prison systems should overcome their fear of being labeled “cruel” but utilize promoting the reality of the facilities for the full impact as a deterrent. The plea agreements should be an easy quick death or a slow agonizing one lasting decades in a windowless box without ever seeing or hearing another human with all the comforts concrete can afford.

Bree says:

I don’t want to know about statisics. When it comes down to it its just morally and ethically wrong. The dealth penalty however it is administered is just crime creating crime. taking somebodys life for whatever reason is MURDER. As for the cost invloved, well that speaks for itself. DP is an easy way out. They deserve to rot in jail forever (not a hotel-like ones that seem to be apperaing today either).

CMF says:

Well Heres my 2 cents. If you killed somebody eventually you may regret it. So If your put on death row and then you die your pretty much doing them a favor then they don’t have to wallow in their own guilt. They should be placed in a jail cell unlike the Hotel california ones you see where they get degrees and watch tv and whatnot. They should be stuck in a 2×2 cubicle to do nothing but think about what you did and why you will be there the rest of your damn life. Make the person so damn horrid that they would want to die rather than sit in that cell to think about what they have done.

Logan says:

Here is what I think: Many murders get away with twelve years in prison, but those kinds of cases usually have to do with moments of aggression; sudden acts of unplanned adrenaline rushes. The people, who are in serious capital cases, are in there for mass murders that were planned, or were just horrendous crimes. These people get placed in jail for life or are in jail without chance of probation. Some believe that these people can change in time. I don’t believe that. I believe most people that get booked for cases like this are unchangeable. The way I see it is; it is better to take the life of a convicted murderer than, risk the life’s of more innocent victims.

Terry says:

Why don’t we just past a law where if you get caught breaking a robery, assult or murder law then the penalty is lethal injection, i bet the crime rate would go way down, forget about cruel and unusual punishment! Send them straight to God! If you don’t believe in God then well at least they won’t be around anymore.

Rob says:

Cheaper to snuff them than to support them in prisons, 50,000 plus a year each prisoner. Rather put the money into schools than providing food, shelter, HEALTH INSURANCE type coverage and other niceties for our garbage people.

Anthony says:

I agree with most people in supporting lethal injection….why do we want to have our tax dollars wasted on someone who prob murdered and raped another human being??? Why not use the money for AIDS, Cancer, or other charities? I they kill someone…they deserve to die and very horrible death. I think it should be horrifying, slow, and painful to them….I would let them die revive them and kill them again…….thats how death penalty should be…..

Melissa says:

I have thought this over many times now. I don’t think they should be able to have a voice when it comes to their death. The people they killed didn’t get to decide their own fate, why should a criminal? I think it should be an eye for an eye, but aren’t we just as bad for killing them? I agree they should die. What about the person who administers the shot? Are they a murderer now?

UK Girl says:

I’ve gone through all of these comments an really thought about this and i’m so unsure of what I think.
I don’t think that a way to punish someone for taking someone else’s life is to take theirs, taking another persons life is WRONG full stop, so how can one be condemed and punished for murder by having another person “murder” them?
I think that they should be let to live the rest of their life in jail, so that they have time to think about the things that they cant have, and basically just left to rot!
I don’t think that any person should have the right to say whether another person lives or dies, not a murderer, nor a judge, nor anyone else on this earth.
And alot of people are saying things like “they probably murdered AND RAPED someone” you really don’t know the half of it, why are you jumping to conclusions? Just to make this punishment justifiable?
On the other hand, I think that once you take another persons life, you sacrifice your own, by this i mean that you should NEVER EVER get to live a normal life again! Over here in the UK, when the judge says “i sentence you to life inprisonment” this usually means that you will serve about 25 years in prison, this means that a murderer ageed 20 will be just 45 when he/she is allowed out. I think thats totally rong, life shoudl MEAN LIFE!

Willye says:

If you are a “poor” killer or rapper you will be sentenced to death, but if you are a “rich” killer forget about it!! you will be richier publiching books. (example O.J Simpson)What a shit it Justice system we have.

Jenny thompson says:

I didn’t think we were talking about rappers!!:P lol. I knew it was a crime against decent music but hey isn’t that a bit extreme! i would suggest you go to an english lesson!!!:P x

Courtney says:

I am just a 16 year girl doing a research paper on Capital Punishment. I am all for the death penalty. Why get to keep your life when you have taken one of another. Why get to choose if you get to live? The person you killed didn’t. I am also from Texas and everyone knows we have 5 times more death penalty cases then anywhere else. Thats all I have to say on this subject.

Stephanie says:

To Courtney:

Who are you to play God? Nobody has the right to take anyone’s life except God. Yes I think dangerous people should be punished and kept away from society but not killed. Most people who commit crimes regret it while they spend the rest of their life in prison. If they do not regret it then they need to be in a mental institution receiving mental help. Putting someone away for the rest of their life is enough, we need to stop killing and start understanding!

Jeff says:

Stephanie, If your god is so almight and powerful why does he let people murder other people since god wont act to stop these people we must. I also believe that once a person has recieved the death sentance they should be taken in outside of the courthouse and hanged rope is ceap and can be reused.

Kris says:

Listening to wailing of victims being raped, a 5year old boy, 13yr and a 20yr old disabled watched as their families is brutally tortured .The father was shot 9 times and his 29years son old shot 7 times both died within minutes of each other, as the rest of his kids and wife are force to witness . What exactly should be the punishment for the attackers? Of course for the victims they would choose death for their offenders but is this right thing to do, an eye for an eye. Stephanie in Some ways I like your idea but I would like to do more to my family attackers a slow painful death. Scott, Scott all I can say is wow and my first thought about your posting ‘concentration camp’.

crystal says:

Okay, I’m doing a research project on lethal injection and I was trying to find out how does it affect the heart and lungs because I have to be able to connect it to chemistry as well. So I recieve some good information from this website and I gladly appreciated, but I also think that they should get rid of lethal injection because in my opionion this is a cruel way to die.

Megan says:

I used to be completely for the death penalty, but when I really thought about it lately I came to the conclusion that nobody should decide whether another human should die. Sure it is natural for one human to feel that way towards another if they have hurt their friends or family…but I believe it should be up to God who’s time it is to go. I have even seen that the victims of families sometimes don’t even wish the defendant to be put to death, for some reason…they forgive them. With what Stephanie says, I don’t understand the ‘we need to stop killing and start understanding’ line…should we understand someone who has done something so terrible?? Odd.

Stefan says:

To Scott,
The Bible does indeed say Eye for an eye, but it here is the WHOLE PASSAGE! “You have heard that it was said, ‘Eye for eye, and tooth for tooth. But I tell you, Do not resist an evil person. If someone strikes you on the right cheek, turn to him the other also.
If you are to quote the bible get the whole thing you can’t take content out.
My thoughts on Captial Punishment are…we need to let them rot in prison…for all rape victums I am sorry to say this BUT revenge is never the answer. You shouldnt play the role of god an say…”I am going to take this life from you”. But we are indeed human…so if you want to take someones life I’m sorry for you.

KC Vendetta says:

The Holy Bible prescribes death penalty by stoning for a number of offences, sometimes trivial. To argue partial or whole parts of the bible scripture is mute.

Capital punishment is a difficult subject to discuss as there are many different opinions that all contain some truth about this issue. Some believe it is fair and just to administer the death penalty when criminals take a life or lives, while others think that it is cruel and unusual punishment for civilized societies. Many Christians are divided on this issue as well, with some following the Old Testament law of capital punishment and others choosing the seemingly gentler side of the Bible–the New Testament–as the basis for their opposition to this law. Are these two Testaments in opposition to each other? Since God does not contradict Himself, perhaps we need a deeper understanding of the Bible as a whole.

Where did the idea of capital punishment come from? The first definition in the Webster’s New World Dictionary for the word “capital” is: 1) Involving or punishable by death (originally by decapitation) (a capital offense).

Decapitation was the beheading of those who were convicted of any crime deserving the death penalty (thus Capital comes from the Latin word “capitalis” which means “of the head”). Murder, treason and other high crimes were punishable by death. Usually the state or governments set the standards for carrying out this punishment.

However, before governments established this practice, the idea of capital punishment was first instigated by God in the Old Testament in the Bible.

God establish laws for men to live by. Looking at the Ten Commandments listed in Exodus 20:1-17, we can see that these laws were given for the good of mankind. One of these laws is in verse 13: “Thou shalt not kill.” You may wonder if God said “do not kill,” why He would then decree that a murderer should be put to death. The reason is that the Hebrew meaning of the word translated as “kill” actually means “murder” or “to slay someone in a violent manner unjustly.” So, in the Ten Commandments God is saying, “Thou shalt not murder.”

God’s law of justice for the taking of a life demands that life be taken; yet, God’s spiritual law of mercy and forgiveness grants that a murderer can be forgiven and restored.

We must understand that God instituted civil authorities to maintain order in the earth. God uses them to restrain evil and they should be obeyed for this purpose. In the New Testament we see that even Jesus surrendered to the governing authorities because He was submitted to God.

Leviticus 24:17-22: “And he that killeth any man shall surely be put to death.
18 And he that killeth a beast shall make it good; beast for beast.
19 And if a man cause a blemish in his neighbour; as he hath done, so shall it be done to him;
20 Breach for breach, eye for eye, tooth for tooth: as he hath caused a blemish in a man, so shall it be done to him again.
21 And he that killeth a beast, he shall restore it: and he that killeth a man, he shall be put to death.
22 Ye shall have one manner of law, as well for the stranger, as for one of your own country: for I am the LORD your God.”

Katelynn says:

The death penalty totally teaches us to treat others the way we dont want to be treated. If we kill a killer, we are no better than them. Also, it costs way less to keep a person in prison for life than to kill them in 30 seconds. They need to sit and think about how they treated others and be forced to change and do things in prison to become a better person. If they like who they were, then let them rot in prison. Also, there are people on death row right now that are totally innocent and will not have the chance to be free. If we get rid of the death penalty, we will have many more chances to get these innocent people out of a horrible place they dont deserve to be in.

Kelly says:

I just wanted to ask everyones opinion … what if the murderer or rapist was your son or your daughter that people were talking about putting to death, then how would you feel, It is ok for us to kill someone elses son or daugther,mother or father I would never ask for the death penalty for my son or daughter would you? I know that we do not need to kill someone for them to be punished let them stay in prison and feel the hurt from their families and the victums families forever until their last breath.

jsb says:

i think instead of death penalty, murderers should be sentenced to a 10 minute beating by a dozen UFC fighters everyday for the rest of their lives.

m says:

how is a painless death considered cruel and unusual puishmend to some

jennifer says:

Wow there are a lot of strong points here. i for one am against it and all i have to say is this whole death penalty thing is based on vengance and vengance is a very personal feeling and it shouldnt be something such a “civilized” government should partake in. I agree that by killing someone you rid them of their punishment right then and there. they are no longer suffering in jail. they should be reminded everyday and should have a psychotherapist so when they start to go crazy they can again make them understand and realize the cruelty of their crime. im from texas which has the highest numbers in execution and im not proud to live in a state which doesnt think its any better than its murderes.

Matt says:

Me and my partner Alan are specalizing in the field of criminal justice. we think that over the past years people have lost all discipline, and to bring in something people are scared of will lower all crimes and let the people who are “mad” enough or “mental” enough to be punished for there crimes as they should not be apart of our society.

alan b says:

i agree

alan b says:

furthermore, we cannot let plagues on our society such as this to stay here : anti social elements do not deserve a place in a law abiding society.

alan b says:

overall, i believe that the lethalinjection should be stopped ; imagine if the killer had hung them upside down and starved them before killing them, and then got to be fed and lie3 down before dying – it is not right. you will probably remember the old saying ‘do unto others as you would have done unto yourself’ – do it. punish them as you see fit,but don’t treat them as ascending gods

hunterr83 says:

Anybody who does not support capital punishment should then be forced to pay, via additional taxes, to keep all inmates alive for the rest of their lives who would have otherwise been put to death. Let’s see if they feel the same way after that!

Zack says:

I personally think the death penalty is a good thing! Criminals know full well the consequences of their actions. States dont use this penalty to “murder” those they dont like. They use it to rid society of those unstable and dangerous enough to be a threat to society. If one was to kill someone in my family, I know I would want full justice. A mere fine and some jail time isnt enough for the criminal to learn that murder/rape is intolerable.

Jon says:

I also must agree with the death penalty. Take punishment where punishment is due. Zack is 100% right! I wish I could meet and shake that mans hand! Good job!! A man who does these things knows full and well the consequenses if he gets caught. heck, I think we should bring back the Guillotine just as a scare tactic. Everyone knows what to expect if you rape, or muder. They should not be allowed to live. The one they raped or killed had no choice in the manner, why should we give them the choice? It only seems fair. Thats my Say. Zack, I would love to smoke a cig with you right now. =]Stay strong in your beliefs.

Mandi r. says:

Lethal injection is probebly the best way for a criminal to die. They deserve what they get which should be a slow and painful death!forget the sleepy shot!let those people die!

mel says:

I think the death penalty is not helpful in any way. First of all, two wrongs do not make a right and to be honest killing the person who committed the crime, is basically giving him or her the easy way out. I think it’s better if they suffer in prison and live terrible lives.

anika says:

why cant we be freinds?

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