Case reports of synthetic cannabinoid XLR-11 associated fatalities

•We report the detection of XLR-11 in two postmortem whole blood cases.•We describe a liquid chromatography tandem mass spectrometry method for XLR-11.•We summarize clinical and human performance toxicology casework involving XLR-11.

Synthetic cannabinoids have been available in herbal incense and potpourri products over the Internet and in smoke shops for the last several years. We report the deaths of two individuals that were associated with XLR-11. Specimens were extracted via a liquid–liquid extraction at basic pH into hexane:ethyl acetate and analyzed by liquid chromatography tandem mass spectrometry. For these two case reports, we describe the instrumental analysis and extraction methods for XLR-11, toxicological results for postmortem blood specimens, relevant case information and autopsy findings. We also briefly review any previously published peer-reviewed reports in which XLR-11 was analytically confirmed and determined to be an intoxicating agent.