Thirteen Cases of Valeryl Fentanyl in Michigan: A Call for Expanding Opioid Testing.

In this report, we describe 13 cases of drug overdose in Michigan in which valeryl fentanyl was found in postmortem blood. Valeryl fentanyl is a schedule I opioid that is rarely found in drug overdoses in the United States. Although little data exist on the mortality and morbidity associated with valeryl fentanyl, its molecular structure indicates that it would be less potent than fentanyl.When analyzing blood samples for valeryl fentanyl, samples from peripheral sites were sometimes negative for quantitative levels; however, samples from central sites in the same decedent were positive. This could indicate unique pharmacokinetics for valeryl fentanyl, which could have implications for other fentanyl analogs. Given the paucity of pharmacodynamic information, the prohibition of its use, the potential to buttress law enforcement efforts in monitoring drug trafficking trends, and to determine the efficacy of current regulations, laboratories should test for valeryl fentanyl. When testing for valeryl fentanyl, and likely other fentanyl analogs, the site of sample collection is important: central sources of blood are preferred to peripheral sources.