evidence: Fentanyl As A Dark Web Profit Center, From Chinese Labs To U.S. Streets More than 70,000 Americans died from drug overdoses last year, and a growing number of those deaths are attributed to the powerful synthetic opioid fentanyl. Journalist Ben Westhoff says the drug, while an important painkiller and anesthesia medicine in hospitals, is now killing more Americans annually as a street drug than any other in U.S. history. [...] He adds: "Since only 2 milligrams of fentanyl is enough to kill you, just the slightest miscalculation can make people overdose and die. ... If fentanyl starts taking over prescription pills and other drugs, the problem could get even worse."