March 22, 2023
Xylazine is an alpha-2 adrenergic agonist and veterinary drug that has become an adulterant commonly encountered in the recreational drug supply, most commonly among opioid and “dope” samples (e.g., fentanyl, heroin). As an adulterant, xylazine elicits pharmacologically advantageous effects alongside fentanyl which can be described as synergistic or prolonging in nature. Xylazine exposure or ingestion can lead to profound sedation and altered mental status. Severe adverse effects of xylazine use include skin ulcerations or wounds. Chronic use of xylazine may result in physiologic dependence and withdrawal symptoms can arise when use is ceased. Since 2021, more than 90% of “dope” samples tested from Philadelphia, PA, have contained xylazine and fentanyl, with xylazine purity (or concentration) ranging from less than 5% to greater than 70%. An increase in xylazine content among these samples has also been observed over this time frame. Due to prevalence and continued geographical spread of xylazine-adulterated fentanyl across the United States, lateral flow immunoassay test strips have been developed as a new tool to allow for field-based drug checking to determine whether or not a sample contains xylazine (similar to the prior process and philosophy associated with fentanyl test strips). To this end, xylazine test strips were obtained and evaluated to determine their accuracy and efficacy.