Equally illicit fentanyl and carfentanil are extremely dangerous opioids that will bring on a quick overdose and death when abused, but carfentanil is a lot more powerful than fentanyl. Several doses from the anti-overdose drug naloxone (Narcan) will not be effective to reverse an overdose. Proceed reading throughFentanyl OD or W/D!!! Unsure, will