Fentanyl shows up where people don't expect it. It gets pressed into counterfeit pills made to look like oxycodone or Xanax. It gets mixed into heroin, cocaine, and other street drugs. That means a person can take fentanyl without ever choosing it. This matters because fentanyl is potent, and a small amount can stop someone's breathing. Learning the signs is practical, not paranoid. When you can spot fentanyl use in your loved one early, you have time to act.