"At least a decade after Xylazine became a fixture in Puerto Rico, it entered the street opioid supply in Philadelphia as a more prevalent additive in the mid-2010s. The shift was noted by PWID, as well as harm reductionists and city public health officials (Johnson et al., 2021). PWID began to describe xylazine – often referred to as tranq – as a known element of specific ‘stamps’ or brands of opioid products in the illicit retail market. Opioid formulations containing xylazine, (e.g.,'tranq dope') became largely sought-after, as the addition of xylazine was reported to improve the euphoria and prolong the duration of fentanyl injections, in particular, solving 'the problem' of the 'short legs' of the otherwise euphoric effects of illicitly manufactured fentanyl."


Friedman, J., Montero, F., Bourgois, P., Wahbi, R., Dye, D., Goodman-Meza, D., & Shover, C. (2022). Xylazine spreads across the US: A growing component of the increasingly synthetic and polysubstance overdose crisis. Drug and alcohol dependence, 233, 109380. doi.org/10.1016/j.drugalcdep.2022.109380.