Lethal Injection Drugs' Efficacy And Availability For Federal Executions

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The Justice Department's announcement that the federal government will resume its use of capital punishment has raised questions about the drugs it plans to use.

After a years-long hiatus in executions, the government will switch its lethal injection method. In the announcement, Attorney General William Barr said, instead of the usual combination of three drugs, federal executioners will now use pentobarbital, a single drug used by states including Georgia, Missouri and Texas.

Though the Department of Justice did not comment on the reason for the change, it may be related to lawsuits that followed botched executions conducted with the three-drug method.

However, this new single-drug method comes with its own set of problems, according to experts in lethal injection. And other types of lethal injection have resulted in failed or painful executions. The following are the most common drugs and methods used in lethal injection, and the controversies they have provoked.

The three-drug cocktail

The three-drug method, which is the most recent protocol in about two dozen states, typically involves the following steps: First, a barbiturate that acts as a sedative and painkiller, usually sodium thiopental; second, a neuromuscular blocking drug such as vecuronium bromide, which arrests nearly all of the body's muscles; and third, a lethal dose of potassium chloride to stop the heart.

This method has run into controversy because sodium thiopental is short-acting, and so may sometimes wear off before the third step is administered — and potassium chloride is excruciating unless the person is completely sedated. But once the second step, the neuromuscular blocking drug, is administered, it's tough to tell if somebody's in pain because they cannot move or cry out.

"You look like you're perfectly placid, but you could be suffering horrifically," says Paul Enzinna, an attorney at Ellerman Enzinna representing the plaintiffs in a lawsuit challenging the legality of the federal procedure of lethal injection.

Pentobarbital

This latest method that the Justice Department has decided to use works "essentially [like] an overdose," says Jonathan Groner, a professor of surgery at the Ohio State University College of Medicine who has written extensively on the death penalty. Pentobarbital is similar to sodium thiopental, but is longer-acting.

By just injecting pentobarbital, the current method will cause a person's central nervous system to shut down in a manner similar to other barbiturate overdoses. This eliminates the potential for silent agony caused by the muscle paralysis and subsequent potassium chloride injection.

But the pentobarbital method is not without its problems, either, in large part because U.S. pentobarbital supply for executions is limited. One of the drug's main manufacturers, a European company called Lundbeck, has not sold to the U.S. for executions since 2011. So states that use it sometimes have to take matters into their own hands, with occasionally questionable results.

In Texas, for instance, state executioners have used versions of the drug made by compounding pharmacies, firms that make versions of other drugs. The versions of pentobarbital these firms produce may be contaminated or not potent enough, resulting in painful or botched executions. As Buzzfeed News reported last year, Texas inmates injected with locally made pentobarbital writhed on the floor, screamed in pain and said they could feel themselves "burning."

The DOJ declined to comment to NPR on how it plans to procure its supply of pentobarbital.

Midazolam

Midazolam, a benzodiazepine, is often used in place of pentobarbital or sodium thiopental. It's meant to behave in a similar way as a sedative, often as part of the three-drug cocktail.

But anesthesiologists have warned that midazolam may not be effective as a painkiller in lethal injections; moreover, its side effects can be excruciating. The drug has also come under fire for its role in several botched executions, including that of Clayton Lockett in 2014 in Oklahoma. Lockett's execution took 43 minutes, during which his vein exploded.

Other methods

Additional drugs currently used by various states for lethal injections include fentanyl citrate, an opioid that can be fatal in small doses; etomidate, another short-acting anesthetic used in three-drug cocktails; and hydromorphone, a powerful painkiller with side effects including extreme burning sensations, muscle spasms and seizures.

An overarching problem surrounding these drugs is that most haven't been thoroughly tested to show efficacy and relative painlessness, says Groner. The landscape of lethal injection drugs, he says, is "very, very unregulated, [and] very untested."

"And the irony is, [Thomas] Edison did a lot of testing for the electric chair."