Used as a veterinary sedative and not approved for human use, xylazine has been increasingly linked with opioid overdose deaths in the United States. A growing number of people have been exposed to xylazine in the illicit opioid supply (especially fentanyl) or in other drugs, particularly in some areas of the Northeast. Xylazine is an α-2 adrenergic agonist that decreases sympathetic nervous system activity. When combined with fentanyl or heroin, it is purported to extend the duration of the opioid’s sedative effect and to cause dependence and an associated withdrawal syndrome; however, data to support these concerns are limited. Despite the escalating frequency of detection of xylazine in people with nonfatal and fatal opioid overdose, direct links to these outcomes have not been identified. Because the strongest causal link is to fentanyl coexposure, ventilatory support and naloxone remain the cornerstones of overdose management. Xylazine is also associated with severe tissue injury, including skin ulcers and tissue loss, but little is known about the underlying mechanisms. Nonetheless, strategies for prevention and treatment are emerging. The significance and clinical effects of xylazine as an adulterant is focused on 4 domains that merit further evaluation: fentanyl-xylazine overdose, xylazine dependence and withdrawal, xylazine-associated dermal manifestations, and xylazine surveillance and detection in clinical and nonclinical settings.

中文翻译：

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国家药物滥用研究所临床试验网络会议报告：管理在急诊、医院和成瘾护理机构中接触甲苯噻嗪掺假阿片类药物的患者

赛拉嗪用作兽用镇静剂，未获批准用于人类，在美国，赛拉嗪与阿片类药物过量死亡的关系越来越密切。越来越多的人在非法阿片类药物（特别是芬太尼）或其他药物中接触到甲苯噻嗪，特别是在东北部的一些地区。 Xylazine 是一种 α-2 肾上腺素能激动剂，可降低交感神经系统活性。当与芬太尼或海洛因结合使用时，据称可以延长阿片类药物的镇静作用持续时间，并导致依赖性和相关的戒断综合症；然而，支持这些担忧的数据有限。尽管在非致命和致命阿片类药物过量患者中检测到甲苯噻嗪的频率不断增加，但与这些结果的直接联系尚未确定。由于最强的因果关系是芬太尼共暴露，因此通气支持和纳洛酮仍然是过量管理的基石。赛拉嗪还与严重的组织损伤有关，包括皮肤溃疡和组织损失，但对其潜在机制知之甚少。尽管如此，预防和治疗的策略正在出现。赛拉嗪作为掺杂剂的重要性和临床效果集中在值得进一步评估的 4 个领域：芬太尼赛拉嗪过量、赛拉嗪依赖和戒断、赛拉嗪相关皮肤表现以及临床和非临床环境中赛拉嗪的监测和检测。