Post-mortem review of fentanyl-related overdose deaths among identified drug users in Southern Bavaria, Germany, 2005-2014.

•Cohort of 242 people belonging to the drug scene with post mortem fentanyl detection.•Fentanyl-related deaths are associated with the launching of transdermal matrix patches.•Fentanyl was mostly extracted from fentanyl transdermal matrix patches and injected.•Tamper-resistant formulations is a promising approach to reduce the number of deaths.