Propofol and propofol glucuronide concentrations in hair following medical propofol administration and in forensic death cases

Purpose: Propofol is the most preferred drug for general anesthesia as well as for analgosedation. However, the rate of abuse cases has increased in the past decade. Hair analysis is considered as the method of choice to determine chronic drug use, and propofol and propofol glucuronide have already been used to confirm previous propofol administration. However, given its frequent medical use, it is important that nonmedical propofol abuse can be distinguished from medical propofol application. Methods: Nineteen hair samples collected from living subjects who received different doses of propofol in the setting of medical treatment and 31 hair samples from forensic death cases with indications of previous propofol administration were examined using our previously described method enabling the simultaneous extraction of propofol and propofol glucuronide from hair followed by validated liquid chromatography–tandem mass spectrometry analyses. Results: Recent propofol administration was verified for eight of 19 living cases and 29 of 31 deceased cases. Of the living cases, propofol glucuronide could be detected in all eight cases, whereas propofol could only be detected in three of these cases. Propofol glucuronide could be detected more frequently and in higher concentrations than propofol following medical propofol administration and observed concentrations varied more widely. Conclusions: Although further research is still required to clarify the mechanisms involved in propofol incorporation into hair and to establish reliable cutoff concentrations for the differentiation of medical from nonmedical propofol use, it seems likely that relatively high concentrations of propofol found across multiple hair segments strongly suggest a nonmedical propofol abuse.