An editorial from Scientific American points out that executions by lethal injection are putting innocent patients at risk. The supply of tranquillizers like propofol (used in routine procedures like colonoscopies), all or in part, comes from Europe, and the E.U. prohibits export of drugs that are to be used to kill people.

Perhaps the root problem is here:

…executions are not medical procedures. Indeed, the idea of testing how to most effectively kill a healthy person runs contrary to the spirit and practice of medicine. Doctors and nurses are taught to first “do no harm”; physicians are banned by professional ethics codes from participating in executions. Scientific protocols for executions cannot be established, because killing animal subjects for no reason other than to see what kills them best would clearly be unethical. Although lethal injections appear to be medical procedures, the similarities are just so much theater.