Two things we know about the opioid drug fentanyl: it’s very dangerous, even a small dose can kill you, and it’s very addictive.  The drug manufacturer Insys knew both of these facts, but it pushed its version of fentanyl, an under-the-tongue tablet supposedly meant for only end-stage cancer patients on physicians and patients to put it into wider use.  The results were often tragic and the company’s now out of business.