There is an ongoing controversy surrounding the drugs drug used for executions. Most states use a three-drug protocol for executions. The protocol consists of sodium thiopental, an anesthetic, which is administered with pancuronium bromide, a paralyzing drug, and potassium chloride, which induces cardiac arrest.
The three drug protocol has was reviewed by the U.S. Supreme Court in Baze v. Rees, 553 U.S. 35 (2008). The Court found that three drug lethal injection did not violate the Eighth Amendment ban against cruel and unusual punishment.
A few states like Ohio, Washington and Arizona have moved to a single drug protocol. A hand full of states— Oklahoma, Texas, Ohio and Arizona—have moved from using sodium thiopental to pentobarbital an anesthetic used primarily for animals. Ohio has used just a single lethal dose of pentobarbital.
Sodium thiopental has become exceedingly hard to get. The American manufacturer of sodium thiopental has discontinued the drug. The shortage has induced states to use pentobarbital for executions. The New York Times recently provided a comprehensive review of the two execution drugs and how they work.
The two drugs come from the same family: barbiturates, drugs that depress the central nervous system. Dr. John Dombrowski, director of the Washington Pain Center and a board member of the American Society of Anesthesiologists told the Times, “it’s like if you ask me what’s the difference between Johnnie Walker Blue, Black and Red — they’re all scotch.” Sodium thiopental has been commonly used as an anesthetic in hospitals.
Pentobarbital has a few medical uses in humans, but is often used by veterinarians to anesthetize or euthanize animals. It has also been used in physician-assisted suicide in Oregon and in Europe. When injected into the bloodstream, both drugs “cross the blood-brain barrier very efficiently,” said Dr. Scott Segal, chairman of the department of anesthesiology at Tufts Medical Center in Boston. “They get into brain tissue itself.”
“All barbiturates put the brain to sleep by slowing down brain function,” Dr. Mark A. Warner, president of the American Society of Anesthesiologists told the Times. “The brain cells that drive the desire to breathe are also suppressed. So any barbiturate, if you give enough of it, somebody quits breathing. Also, if you give enough of it the heart quits pumping as hard and that can cause decreased blood pressure.” But while the way the drugs work might be similar, the effects are different.
Sodium thiopental is used in hospitals because it “has a relatively fast onset and it doesn’t last long,” Dr. Warner said. “You want a patient to go sleep and wake up pretty quickly.” Pentobarbital is a long-acting drug. “If veterinarians are using this, they don’t really care if an animal wakes up faster or not,” Dr. Dombrowski told the Times. “If the dog or cat is still a little sleepy it doesn’t make a difference.”
In euthanizing animals, higher doses are used, and “the lethal effect is a cardiovascular effect,” Dr. Segal said, meaning that it stops the heart. Pentobarbitol is used in hospitals in certain circumstances, like inducing a coma in brain-damaged patients because “that allows the brain to use more energy and oxygen to repair itself,” Dr. Warner told the Times. He said it can also be used to stop seizures in patients for whom other drugs are ineffective.
Opponents of the death penalty object to both drugs. Some say thiopental can wear off too quickly, allowing inmates to feel pain. Others object to using pentobarbital, because it is so infrequently used in humans. Executions using pentobarbital have been successfully carried out in Ohio and Oklahoma.
To read more: http://www.nytimes.com/2011/04/10/weekinreview/10injection.html?_r=1