Distribution of furanyl fentanyl and 4-ANPP in an accidental acute death: A case report

Fatalities from emerging synthetic opioids have continued to reach new epidemic proportions throughout the world in recent years. Due to the sparsity of research in new opioid analogs, commonly observed lethal concentrations and their distribution following death have yet to be well documented. The prevalence of furanyl fentanyl in postmortem casework contributes to the opioid related deaths that are amongst half of drug-induced fatalities in the United States. In this case study, a 23-year-old man was found dead in San Francisco following the ingestion of blue pills imitating oxycodone. Initial toxicology screening did not detect oxycodone in blood. However, a positive fentanyl immunoassay result was obtained and analysis of the pills collected at the scene showed the presence of furanyl fentanyl. Analysis of postmortem samples revealed concentrations of furanyl fentanyl at 1.9 ng/mL in peripheral blood, 2.8 ng/mL in cardiac blood, and ∼55,000 ng in gastric contents. Metabolite 4-anilino-N-phenethyl-piperidine (4-ANPP) was also confirmed at 4.3 ng/mL and 5.8 ng/mL in peripheral blood and cardiac blood, respectively. Trace amounts of both analytes were detected in urine and the vitreous humor. Liver 4-ANPP concentrations of >40 ng/g were also detected. This case study of acute furanyl fentanyl overdose in a young male thought to be using oxycodone highlights illicit drug users are often subject to unknown drug entities. The toxicological analysis provides preliminary information of the distribution of furanyl fentanyl and its metabolite in a range of postmortem specimens and collection sites.