That's the Scientific American's latest Ask the Expert topic. Larry Greenemeier's column is subtitled, "Is Capital Punishment by Lethal Injection Quick and Painless?"
Lethal injection is used for capital punishment by the federal government and 36 States, at least 30 of which use the same combination of three drugs: sodium thiopental (a barbiturate to induce anesthesia), pancuronium bromide (a muscle relaxant that paralyzes all the muscles of the body) and potassium chloride (a salt that speeds the heart until it stops). This protocol was developed in 1977 for the state of Oklahoma by then–Chief Medical Examiner Jay Chapman, but it has never been codified or sanctioned by the U.S. Food and Drug Administration (FDA).
Regardless of whether Landrigan's legal team was simply using the drug shortage as stalling tactic, their legal maneuvering brings to the fore a contentious dispute over the science (or some would say lack thereof) behind lethal injection executions in the U.S. For more than two decades, it has been argued that the FDA should be required to certify the safety and effectiveness of drugs used to carry out executions (as it does for drugs used to euthanize animals). The FDA, wanting to stay out of the capital punishment debate, disagrees.
In 2008 the U.S. Supreme Court (pdf) upheld a lower court ruling that the state of Kentucky's three-drug method of lethal injection did not constitute "cruel and unusual punishment," as defined by the Eighth Amendment. Some scientists disagree. Scientific American spoke with University of Miami Miller School of Medicine molecular biologist Teresa Zimmers about this controversial topic.
You and a group of colleagues in 2007 published a report in PLoS Medicine that examined public records of executions. What was the purpose, and what sort of reaction did you receive?
We were actually trying to look at whether there was any evidence that the three-drug protocol—sodium thiopental, pancuronium bromide and potassium chloride—acted in the way it was supposed to act. We analyzed the time to death or the time to different events, such as cardiac arrest, in order to understand what might be the mechanism of death. We found no evidence to support the use of this protocol, the dosage of the drugs or the order in which the drugs were administered in executions.
A lot of responses to the study were negative—people assumed that we had a specific political agenda. This began to change as people looked at our data more closely.
Why is sodium thiopental used as part of a lethal injection execution?
Sodium thiopental was chosen to render the person deeply unconscious and unable to feel the paralysis brought on by the pancuronium bromide, which causes the person to lose the ability to breathe. And the potassium chloride is extremely painful. Some people have said that three to five grams of sodium thiopental alone should be enough to induce death. [In December 2009 Ohio became the first state to use a single dose of sodium thiopental to execute death-row inmates.] We looked at whether inmates died reliably after the sodium thiopental, and it's not clear this is the case. We also determined that the doses of sodium thiopental used are not always as "massive" as claimed. It's not even clear how much a massive dose is in this context. We found that, at most, the highest doses were two times the lethal dose for animals, regardless of the inmate's weight.
It has been reported that in addition to a shortage of sodium thiopental, the doses that some states stockpile are set to expire before scheduled executions can be carried out. What sort of shelf life does sodium thiopental have?
Sodium thiopental has quite a long shelf life—up to 48 months in its unconstituted form. Once you add liquid, it's been reported to be stable for 24 hours or, if it's kept cold, it can last for seven days. They typically prepare it on the day of execution. Shelf life may be a problem because states perform executions infrequently and now don't have a supply of new doses.
More on the 2007 Florida study at:
Some posts examining the origins of lethal injection execution protocol:
Related posts are in the lethal injection index.