The American Pharmacists Association has put in place an official ban on members participating in lethal injections or other executions, saying "such activities are fundamentally contrary to the role of pharmacists as healthcare providers."
Hospital Says It Was Tricked Into Selling Drugs for an Execution

When Louisiana ran out of lethal injection drugs this year, officials announced the state would switch to a new two-drug cocktail. But what they apparently failed to disclose was that the new drugs had been purchased from a hospital that thought it was healing prison hospital patients.
Oklahoma Wants To Use Animal Euthanasia Drug on Death Row Inmate
What do you do if you're a state executioner facing a shortage of drugs for lethal injections? You improvise. That's what Oklahoma is trying to do, by using pentobarbital — the same drug used to euthanize animals — on humans.