I wondered why they executed criminals with a drug that was difficult to administer and was unpredictable at times. Pentabarbital is a good drug for euthanasia; given slowly it is humane and the animal goes under smoothly. I always use ten percent more than the lethal dose because I don’t wish to be on the news for failing to euthanize an animal.
Why do you think this drug wasn't used on humans before now, perhaps because it is usually reserved only for euthanizing animals?