Both illicit fentanyl and carfentanil are exceptionally unsafe opioids that will result in A fast overdose and Loss of life when abused, but carfentanil is more powerful than fentanyl. Several doses on the anti-overdose drug naloxone (Narcan) might not be effective to reverse an overdose. Go on looking throughRe: Seriously Freaked Out!! Fentanyl OD