Sarah Laurel, a harm-reduction professional, sat behind her desk and asked the man who walked into her store how much he’d been paid to be in a viral video she’d recently watched. The man was an active substance user, struggling with addiction, who had probably taken drugs on the streets of Kensington, Philadelphia, earlier that morning. His answer was $50. Sarah laughed and said that was more than usual. Since 2021, Kensington, a low-income neighborhood in North Philadelphia, has been ground zero for a new and dangerous sedative called “tranq”. Also known as “xylazine”, a side-effect of this drug can...