Clinical characteristics of patients exposed to medetomidine in the illicit opioid drug supply in Philadelphia - a case series.

Introduction: Medetomidine is an emerging adulterant in the illicit opioid drug supply with minimal data regarding clinical effects or blood concentrations after uncontrolled exposures in humans.

Methods: A retrospective case series was performed of patients presenting to the emergency department after illicit opioid overdose with confirmed exposure to medetomidine. Patient outcomes and clinical data were summarized with descriptive statistics.

Results: Eleven patients were included in the series. Whole blood medetomidine concentrations ranged from 1.2 μg/L to 16 µg/L. Patients had sinus bradycardia for a median of 3.4 h, and hypotension was not common. Six cases were admitted to the hospital, one to the intensive care unit, and all survived. All cases tested positive for fentanyl and xylazine, and other adulterants were common.

Discussion: Sinus bradycardia was the most salient finding of patients with confirmed medetomidine exposure from the illicit opioid supply. Bradycardia resolved within the expected five half-lives determined by early drug studies, and no patient required atropine, electrical pacing, or vasopressors for hypotension. The duration and degree of bradycardia did not correlate well with medetomidine concentrations.

Conclusion: In this retrospective case series, patients who tested positive for medetomidine had sinus bradycardia and required prolonged monitoring.