Ronald Bailey has this over at Reason.

Lethal injection was devised as a "humane" method of execution by an Oklahoma anesthesiologist Dr. Stanley Deutsch in 1977. Deutsch's procedure involves rendering a murderer unconscious with fast-acting sodium pentothal. Typically unconsciousness occurs about 60 seconds after the drug is administered. Next comes an injection of pancuronium that that paralyzes the muscles and stops breathing in 3 to 5 minutes. And finally potassium chloride is injected which stops the murderer's heart. Death occurs usually in seven minutes to ten minutes. Texas was the first state to use it to execute a murderer in 1982. Since then it has become the overwhelmingly popular method of execution in the 37 states that have the death penalty.

The humaneness of lethal injection was brought into question by an article in the April 16, 2005 issue of the British medical journal The Lancet. The article argued that a postmortem analysis of blood from 43 of 49 executed prisoners indicated that they may not have received enough sodium pentothal to insure unconsciousness. In which case, the murderers might have felt themselves asphyxiating after being injected with pancuronium and as well as an intense burning sensation in their veins as the potassium chloride flowed toward their hearts. "Failures in protocol design, implementation, monitoring and review might have led to the unnecessary suffering of at least some of those executed," concluded the Lancet article.

***

As harsh as it sounds, if lethal injection is good enough to end the suffering of a beloved pet, it's probably too good for a pre-meditated murderer.

And that is where Bailey misses the boat. If the same lethal injection method used to kill people was used to kill a pet, in almost every state in the country the vet would lose his license. The American Veterinarian Medical Association guidelines on acceptable and unacceptable methods of animal euthanasia. The method used in every state in the Union violates those guidelines. As the Amici in Hill note:

The primary goal of veterinarians who euthanize animals is to achieve death in the most humane manner possible, avoiding pain and suffering of the patient. The manner in which the combination of drugs are administered to prisoners according to Florida'’s lethal injection protocol, fails to comport with the minimum standards for the humane euthanization of animals in several respects. The preferred method for humane euthanasia by veterinarians involves the use of a single drug: an overdose of sodium pentobarbital. Sodium pentobarbital is a stable and long-lasting anesthetic, which places the patient in a deep "surgical plane of" anesthesia, which then progresses to apnea as a result a respiratory depression, and then cardiac arrest. The advantages of such a method are speed of action; minimal or transient pain merely associated with the injection; and cost. 2000 Report of the American Veterinary Medical Association Panel on Euthanasia, 218 J. Am. Veterinary Med. Ass'’n 669, 679-80 (March 1, 2001) .

The cruel irony in all of this is that for a decade now capital defense lawyers have all but conceded that the AVMA is arguably the gold standard in euthanasia. Veterinarians are all too often called to end the lives of a beloved animal, including animals as large as a horse or gorilla. Put simply, much of the problem currently surrounding the manner of ending life could be resolved, as one pleading I have read stated, by simply granting the request to "treat him like a animal."