Fentanyl, along with other opioids such as heroin and morphine, bind to receptors in the brain. After repeated opioid use, the brain adapts to the drug, so users require more drug to experience the same effects. This may result in addiction. If the drug use is stopped, withdrawal symptoms can be severe.
A tiny dose of fentanyl, as small as 3 grains of salt, can be fatal depending on a person’s previous exposure to opioids. Because fentanyl is so powerful, overdose can occur when a person doesn’t know the dose they are taking. Medicines ordered online or obtained outside of a licensed pharmacy may be counterfeit and could contain fentanyl. Fentanyl may be added to other illegal drugs, so users may not know they are taking a substance that contains fentanyl. Fentanyl cannot be identified through sight, smell or taste. Pills with fentanyl may look like regular prescription pills or be brightly colored like candy.