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A Retrospective Toxicology Study of Polysubstance Use Patterns Associated with Xylazine
Wanzhu Zhao1, Carlos Goncalves1, Emily Ruggiano1
1iC42 Toxicology, Department of Anesthesiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
International Journal of Molecular Sciences
|February 27, 2026
Summary
Xylazine is increasingly found in illicit drug supplies, altering consumption patterns. Testing positive for xylazine in urine may indicate exposure to novel psychoactive substances, suggesting its use as a marker for advanced drug screening.
Area of Science:
- Forensic Toxicology
- Analytical Chemistry
- Pharmacology
Background:
- Xylazine is increasingly used as an adulterant in illicit drugs.
- Understanding drug use patterns associated with xylazine is crucial for public health.
- Identifying novel psychoactive substance (NPS) exposure is a growing challenge.
Purpose of the Study:
- To investigate drug use patterns in xylazine-positive versus xylazine-negative urine samples.
- To determine if xylazine can serve as a marker for NPS exposure.
- To analyze trends in drug circulation within a specific patient population.
Main Methods:
- Retrospective analysis of urine toxicology results from patients with substance misuse.
- Utilized two analytical platforms: targeted LC-MS/MS and non-targeted high-resolution mass spectrometry.
- Statistical analysis to compare drug patterns and concentrations between xylazine-positive and -negative groups.
Main Results:
- Statistically significant differences in drug use patterns were observed between xylazine-positive and -negative samples (p < 0.001).
- Xylazine-positive samples showed significantly higher concentrations of designer drugs/new psychoactive substances (p < 0.0001).
- Overall drug concentrations (normalized to creatinine) were higher in xylazine-negative samples.
Conclusions:
- Xylazine is becoming more prevalent in illicit drug circulation.
- Xylazine can potentially serve as a marker to prompt further testing for designer drugs/NPS.
- Non-targeted mass spectrometry assays are valuable for identifying unknown substances in complex drug samples.
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