Bradycardia Linked to Xylazine Detection in Opioid Overdose in ED

FRIDAY, Jan. 16, 2026 (HealthDay News) — Bradycardia is associated with an increased likelihood of xylazine detection in adults in the emergency department (ED) with suspected opioid overdose, according to a study published online Jan. 13 in Addiction.

Noting that xylazine is increasingly being detected in illicit opioid supply, Jennifer S. Love, M.D., from the Icahn School of Medicine at Mount Sinai in New York City, and colleagues conducted an observational study to examine the demographic and clinical factors associated with xylazine detection among adult patients in the ED with opioid overdose. Patients were enrolled from September 2020 to September 2023 in 10 institutions across nine states in four regions of the United States.

A total of 1,289 patients were eligible for inclusion in the Fentalog Study. Patients were categorized into those with and without xylazine detected. The researchers found that xylazine was detected in 238 patients, who were mainly male, White, non-Hispanic, and located in the Northeast United States (78, 48, 82, and 75 percent, respectively). The likelihood of xylazine detection was higher in association with bradycardia on initial ED vital signs (adjusted odds ratio, 2.11).

“Within this niche subgroup of patients who were exposed to xylazine-adulterated fentanyl and had an overdose, bradycardia is the only significant “signal” we have found so far of relating blood test results to a clinically meaningful marker for physicians when it comes to symptoms,” Love said in a statement.

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