Friedman Joseph R, González Montoya Alejando, Ruiz Carmina, González Tejeda Mariana A, Segovia Luis A, Godvin Morgan E, Sisco Edward, Pyfrom Elise M, Appley Meghan G, Shover Chelsea L, Pacheco Bufanda Lilia
J Addict Med. 2025 Mar 20. doi: 10.1097/ADM.0000000000001474.
Xylazine is a veterinary anesthetic increasingly present alongside illicit fentanyl in the United States and Canada, presenting novel health risks. Although xylazine remains less common in the Western US, Mexican border cities serve as key trafficking hubs and may have a higher prevalence of novel substances, but surveillance there has been limited.
We examined deidentified records from the Prevencasa free clinic in Tijuana, describing urine and paraphernalia testing from patients reporting using illicit opioids within the past 24 hours. Xylazine (Wisebatch and Safelife brands), fentanyl, opiate, methamphetamine, amphetamine, benzodiazepine, and nitazene test strips were used to test urine and paraphernalia samples. Paraphernalia samples were also analyzed with mass spectrometry.
Of n=23 participants providing urine and paraphernalia samples concurrently, 100%, 91.3%, and 69.6% reported using China White/fentanyl, methamphetamine, and tar heroin, respectively. The mean age was 41.7 years, 95.7% were male, 65.2% were unhoused, and 30.4% had skin wounds currently. Xylazine positivity in urine for the 2 strip types used was 82.6% and 65.2%. For paraphernalia testing, the xylazine positivity was 65.2% and 47.8%. Confirmatory testing of paraphernalia samples by mass spectrometry indicated a 52.2% xylazine positivity, as well as fentanyl (73.9%), fluorofentanyl (30.4%), tramadol (30.4%), and lidocaine (30.4%). Mass spectrometry suggested lidocaine triggered n=3 and n=0 false positives among the xylazine test strip types.
Xylazine is present on the US-Mexico border, requiring public health intervention. High lidocaine positivity complicates the clinical detection of xylazine via testing strips. Routine urine testing for xylazine in clinical scenarios is likely feasible, yet confirmatory urine studies are needed.
在美国和加拿大，赛拉嗪作为一种兽用麻醉剂，越来越多地与非法芬太尼一同出现，带来了新的健康风险。尽管赛拉嗪在美国西部仍不太常见，但墨西哥边境城市是主要的贩运枢纽，可能有更高比例的新型物质，不过那里的监测一直有限。
我们检查了提华纳Prevencasa免费诊所的匿名记录，描述了过去24小时内报告使用非法阿片类药物的患者的尿液和用具检测情况。使用赛拉嗪（Wisebatch和Safelife品牌）、芬太尼、阿片类、甲基苯丙胺、苯丙胺、苯二氮卓和硝氮烯试纸条检测尿液和用具样本。用具样本也用质谱法进行了分析。
在同时提供尿液和用具样本的n = 23名参与者中，分别有100%、91.3%和69.6%的人报告使用了“中国白”/芬太尼、甲基苯丙胺和焦油海洛因。平均年龄为41.7岁，95.7%为男性，65.2%无家可归，30.4%目前有皮肤伤口。所使用的两种试纸条检测尿液中赛拉嗪阳性率分别为82.6%和65.2%。在用具检测中，赛拉嗪阳性率为65.2%和47.8%。用具样本的质谱确证检测显示赛拉嗪阳性率为52.2%，以及芬太尼（73.9%）、氟芬太尼（30.4%）、曲马多（30.4%）和利多卡因（30.4%）。质谱分析表明，利多卡因在赛拉嗪试纸条类型中分别引发了n = 3和n = 0次假阳性。
赛拉嗪出现在美墨边境，需要公共卫生干预。高比例的利多卡因阳性使得通过试纸条临床检测赛拉嗪变得复杂。在临床场景中对赛拉嗪进行常规尿液检测可能可行，但仍需要进行确证性尿液研究。
