The Appearance of Xylazine in the United States as a Fentanyl Adulterant.

Importance: Use of xylazine in the United States as an adulterant for drugs of abuse has increased in recent years, thus it is important for health care providers to understand the basic pharmacology and toxidrome of the drug, as well as management options for patients who have overdosed. Observations: Data obtained from studies between 2006 and 2022 indicate a rapidly increasing incidence of xylazine overdose in the United States, with overdose cases now being seen in 25 states. Hallmark symptoms of xylazine overdose include respiratory depression, bradycardia, hyperglycemia, central nervous system depression, and initial hypertension turning to unstable blood pressure. Xylazine overdose is not reversible with naloxone and requires supportive measures. Conclusions and Relevance: It is important for health care providers to be aware of presenting symptoms in xylazine overdose so that proper care can be provided. Facilities may consider adding xylazine to their routine toxicology report to aid in patient management and better assess the incidence of xylazine use as an adulterant in a given geographic area. Prim Care Companion CNS Disord 2023;25(6):22nr03473 . Author affiliations are listed at the end of this article.