An autopsy case of acetyl fentanyl intoxication caused by insufflation of ‘designer drugs’

•The first report of an autopsy case of acetyl fentanyl delivered by insufflation.•Narrow range between the effective dose (ED50) and the lethal dose (LD50).•The awareness of medical professionals concerning the effective use of naloxone.•The need to establish a comprehensive system for toxicological analyses.