Both of those illicit fentanyl and carfentanil are particularly hazardous opioids that may bring on a quick overdose and death when abused, but carfentanil is a lot more strong than fentanyl. Many doses in the anti-overdose drug naloxone (Narcan) may not be effective to reverse an overdose. Go on looking throughTruly Freaked Out!! Fentanyl OD or W/