Both equally illicit fentanyl and carfentanil are extremely hazardous opioids which could cause a quick overdose and death when abused, but carfentanil is a lot more powerful than fentanyl. Numerous doses of the anti-overdose drug naloxone (Narcan) will not be effective to reverse an overdose. Proceed studyingRe: Seriously Freaked Out!! Fentanyl OD