Fatalities Involving Carfentanil and Furanyl Fentanyl: Two Case Reports.

Carfentanil is a fentanyl analog frequently used in large animal veterinary medicine. Recently, carfentanil has been discovered in postmortem and antemortem cases throughout the United States in the heroin supply either alone or mixed with heroin and/or other fentanyl analogs. The potency of carfentanil is ~10,000 times greater than morphine and 100 times greater than fentanyl. In two recent cases, carfentanil was identified and ruled to be the cause of death, either alone or in combination with other drugs. Case 1 involved a known heroin user. He was discovered slumped over in a running van blocking the bays of a carwash. Two syringes, a spoon with cotton and residue and a yellow baggie of powder were found in the van. Case 2 involved a man living in a tent in a park with his mother. He was last heard from by a sister via phone who stated he sounded very intoxicated and by his mother who noted him to be "itching all over" and upset over his girlfriend. When the mother returned from work, she discovered him unresponsive with a small baggie of brown powder next to him. Routine drug and volatile screening tests were performed on heart blood using headspace gas chromatography, immunoassay and gas chromatography mass spectrometry methods. Results from initial testing on both cases did not have any significant toxicological findings. However, due to the history, scene photos, toxicological findings in blood and urine and analysis of the drug paraphernalia on one of the cases which identified carfentanil and furanyl fentanyl, fentanyl analogues were suspected. Heart blood was sent to a reference laboratory for carfentanil and furanyl fentanyl analysis. Case 1 had a carfentanil concentration of 1.3 ng/mL and a furanyl fentanyl concentration of 0.34 ng/mL. Case 2 had a carfentanil concentration of 0.12 ng/mL.