The emergency call came in simply as a person down. It could have meant any number of things, says former Atlanta-area paramedic Kevin Hazzard. The patient might have been a diabetic whose blood sugar was too low or someone who’d had too much to drink. But when Hazzard arrived on the scene, it was clear the young woman had overdosed on heroin. “She was just lying there,” Hazzard says. “She was blue. Instantly, I realized she was not breathing.” He reached for the naloxone. It was the first time he’d ever used the opioid overdose antidote, also known by its trade name Narcan. He gave her the full dose all at once. She responded so quickly to the drug—bolting upright, breathing, and then vomiting—that she caused Hazzard and his partner to jump back with fright. It was like waking the dead. This was in 2004, and the opioid crisis was