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Published on: April 28, 2023
Short-Term Outcomes of In-Utero Xylazine Exposure in Infants With NOWS
John Griffin1, Margaret Urschler2, Alina Lopez3
1Department of Pediatrics, School of Medicine, Washington University, St. Louis, Missouri.
Background:
Xylazine is an α2-adrenergic veterinary sedative increasingly detected as a fentanyl adulterant. Its impact on neonatal opioid withdrawal syndrome is unknown.
Methods:
In this retrospective matched cohort study conducted at a level IV neonatal intensive care unit (NICU) between January 2023 and December 2025, infants with confirmed prenatal fentanyl and xylazine coexposure were matched 1 to 1 to fentanyl-only exposed infants on gestational age and sex. Exposure was confirmed by maternal or infant urine or meconium drug screens. Primary outcomes included nursery, NICU, total hospital length of stay (LOS), and rates of nasogastric (NG) tube placement.
Results:
Seventy xylazine-exposed infants were matched to 70 fentanyl-only controls. Groups were similar in birth weight, demographic characteristics, pharmacologic treatment rates, and peak eat, sleep, console scores. Xylazine-exposed infants had significantly longer median hospital LOS (21 vs 15.5 days, P < .01) and higher rates of NG tube placement (74 vs 53%, P = .01). Xylazine-exposed infants had greater polysubstance burden with a higher median number of coexposures (4 vs 2.5, P < .01) and were more likely to have cocaine (64 vs 33%, P < .01) and heroin (44 vs 17%, P < .01) coexposure.
Conclusions:
Prenatal xylazine coexposure is associated with substantially greater clinical resource use compared with fentanyl exposure alone, including longer hospitalization and increased feeding support requirements, potentially reflecting xylazine's sedating and hypotonic effects on neonatal feeding behavior.
