This morning's New York Times features an article explaining the differences between the different chemicals used for executions.
Opponents of the death penalty object to either drug. 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.
In the three-step cocktail common in executions, a barbiturate is given with pancuronium bromide, a paralyzing drug, and potassium chloride, which induces cardiac arrest. Dr. Segal said all three drugs can have lethal effects.
“I’m not sure anyone knows which drug actually kills someone,” he said.
In fact, one can do the job. Ohio has used both barbiturates by themselves in executions.
This discussion comes in the heels of several stays of execution, for reasons unrelated to the technology.